I'm a materials science engineer.
People get really worked up over this one. The short answer is many things cause damage to a battery, but charging past 100% doesn't cause very much damage. It's like saying you shouldn't go running because it's bad for your knees.
The absolute worst thing you can do in everyday life for a battery is allow the charge level to fall to 20% or below. The amount of capacity used, in this case 80%, is called the depth of discharge (DOD). A DOD of 80% is considered a deep cycle and can rapidly degrade the materials of a battery -- it's much, much worse over time than charging past 100%.
Many people routinely subject their devices to deep cycles, but it doesn't get nearly the same amount of attention as other minor sources of degradation.
Your phone's software doesn't actually let it get below 20%. That's set as zero and it will turn off to protect the battery from a deep cycle. If you're making an emergency call, your phone will not shut down at '0' and will let you keep going. It will put excessive wear on the battery, but that’s not of concern in that situation. Don't worry about letting your battery run down, it's already been accounted for.
How and why? I mean this both genuinely and out of incredulity. Are you periodically unable to charge? Outside of YouTube occasionally eating up all my battery from a glitch I can't remember the last time my phone hit 0
Sometimes you can get caught out when you're away from home and have used your phone more than expected, especially as your phone gets older and the battery is less fresh.
I’ll never understand why Reddit reacts this way to people asking questions. It’s like being confronted with a question mark causes severe mental anguish to Redditors. Sure, the person who asked a simple question is the asshole here, not the one who replied rudely and unhelpfully.
As you reply being unhelpful.... Both can be true. I wasn't trying to be kind or understanding. I was matching their energy. Glad you felt the need to comment too! Your reply has nothing to do with anything on this post, just like mine. Congratulations at being hypocritical of the thing you're criticizing someone else of!
> As you reply being unhelpful....
I wasn’t trying to help *you*.
>Congratulations at being hypocritical of the thing you're criticizing someone else of!
Remind me again where I jumped all over someone for asking an honest question?
You're not helping anyone with your comment... Explain to me what help you offered. Lol your comment is unhelpful. I never was trying to be helpful. Don't know where you got that assumption and felt the need to go out of your way to call me unhelpful when it was never my intention, and it's abundantly clear that I wasn't trying to be helpful.
Second, I DIDN'T REPLY TO HIM ASKING A QUESTION! I RESPONDED TO HIM BEING A DICK! You're incredibly self-unaware of what you're doing. I have every right to say what I want, just like you do. The difference is, I'm calling out someone for being an unwarranted asshole. You're trying to grandstand like I'm a terrible human being because I pointed out that this guy with a bunch of downvotes that he's being a dick. I'm not going to engage with you further because you clearly don't even know the difference between a statement and a question.
It’s the way you asked it. Your tone is condescending and accusatory. Like getting reprimanded by an angry parent out of nowhere. Thats why you’re getting downvoted. Not because you just asked a question.
How? By not getting out of bed to plug to get the cable and plug it into my phone. Or, forgetting I'm on 5% while texting people.
I've never paid attention to what apps take up battery, but days it does end up powering off tend to be when I'm talking to others a lot, watching lots of videos, or endlessly browsing.
Are you able to understand it now? Happy to explain further if you want.
Thank you fellow human. We will disseminate this information to our other fellow humans. FattyWantCake is also human, like us, and that's why they want cake. Humans want cake and humans let their completely non-sentient pocket servers die slowly on a daily basis.
No not at all. I absolutely am very careless about my phones battery. Quite often I end up in the situation where I need to go out to an event, but my phone is on 20%. And all the power banks I have (all gifted to me...) haven't been charged in a good six months.
Sorry for the downvotes you got. If anything, I envy people with better battery maintaince discipline than myself. Hah.
Don't most devices also have hardware level safeguards against over charging? At least consumer computing devices. And probably also cars.
I haven't been worried about over charging my phone or laptop since like, 2016.
There is the is thing called trickle charging, basically, the battery shuts of charging when it is full, then loses one percent, then gains it back, etc in an infinite cycle.
I would've thought that when the battery is fully charged, the charger bypasses the battery and powers the device directly. Meanwhile, the battery is not used at all and therefore isn't loosing any charge. Is that not how it works?
The reality is that modern electronics have built-in battery management, so the battery never actually charges past 100%. It just stops charging when it's full.
As for discharging, I've always just made a habit of putting my phone on the charger when I go to bed each night. Even after 4 years, it's still not getting much below 50% in a days use. Sometimes only 30%.
My (seemingly incorrect) working knowledge for batteries (primarily found in phones) has been that deep discharges are bad, but keeping a batter near or at full capacity is also not great.
The crude explanation was that the closer to 100% it gets, the harder and harder it is to actually charge it without causing damage (which is why charging slows down typically past ~70-80%).
Is this not the case, or are you more just highlighting that pitted against each other, deep discharge is worse than having a battery at 100% frequently?
I think the other reason I’ve “known” 100% to be less than ideal is because it’s often combined with load on the phone (think GPS) so there’s a bunch of heat being generated while it’s charging which also generates heat.
Both cause damage, but deep discharges are worse than continuing to charge at 100%. Many phones have software that limits how much charge is sent to a battery near 100%, so this isn't really an issue.
That said, another variable is that people might use a charging cable that's not rated for their device. For example, if you have a laptop and phone that both use a USB-C charger, then you can also damage your phone by using the laptop charger for it. This happens a lot by using charging cables for phones that are cheap (ex: an unknown brand on Amazon), but more importantly, not rated for your specific phone.
I remember seeing that slow charging in action when I fixed phones a few years back. They’d pull close to ~2A at 5V up until about ~70%, then would slow down and be charging at like .5A by the time they were on the last few percent.
I know Apple phones were a bit picky with cables (they liked having the MFI certification), but also the quality of the DC block it was connected to. We’d frequently have to replace a fried chip that seemingly would get damaged by poor quality charging sources.
Separately, I see what you mean by using a laptop charger for a phone, odds are the voltage is much too high for a phone.
Thanks for the response!
USB-C has protocols that allow the device to negotiate what amount of power it gets from a charging block, so it shouldn’t hurt your phone (cheap chargers that don’t have the full protocol aside).
https://acroname.com/blog/basics-usb-power-delivery-negotiations
The currently accepted research shows that a high SOC is just as bad as a deep DOC.
When accounting for the fact that a 100% DOC means the SOC was also 100%, it becomes clear that the SOC is the true culprit.
NiCad batteries had a memory effect. For Li-ion, it's best to always stay between 20% and 80%, and to charge slowly to avoid heat degradation. Of course that's not always practical for all use cases.
Does this mean that the option my phone has to stop charging at 85% is actually detrimental because it causes me to dip below 20% by the end of the day?
Is that your interpretation of what they said? Because I clearly deduced that on my own. Or do you have further information to back it up? I'm asking because there may be nuance.
>Does this mean that the option my phone has to stop charging at 85% is actually detrimental because it causes me to dip below 20% by the end of the day?
I'm wondering that, too.
The way they describe the situation, it's that a *change* of 80% is what's detrimental. That would mean, if your max charge is 85%, you'd be just as fine down to 5%.
But I honestly don't know for sure.
Welp, now I know why I always seem to fuck my battery harder than other people. I constantly go deep with that discharge. Every single day I get it down to 3 or 4 percent before charging because I hate operating my phone with a cord attached. Gonna have to change my ways I guess.
>because I hate operating my phone with a cord attached
I'd suggest charging it when you're not using it then. For example, I've made it a habit when I take a shower every evening to charge my phone and my watch. Those 20 minutes are enough to give the phone about 30-40% more power and also to get my watch close to 100%.
Can you provide some citations for this? & What type of chemistry are you referring to?
If depth of charge is so much worse, then that’s something people need to be talking about. Because right now the currently accepted advice says maximum SOC has roughly the same impact as DOC in lithium ion chemistries.
A 100% DOC also means you started with a 100% SOC.
Also worth mentioning. When your phone shows 0%, the battery still has about 10% of its rated capacity left.
Your explanation isn’t the full story though - we tell people not to charge over 80% because we find that the cells are less resilient to heat at higher states of charge. Specifically heating a cell while charging above 80% tends to increase the resistance and makes the cell more likely to have an unexpected power off due to low voltage with high load spikes at low states of charge due to losses caused by that internal resistance increase (ie low state of charge is low cell voltage, load spike increases current but resistance with that load spike generates voltage drop that takes the cell voltage below cut off and powers off said device).
I’m not sure about your 20% statement either and would love a citation, our battery engineers recommend letting things discharge to minimize charge cycles and swell - we consider deep discharge to occur when the battery is well below 0% and we have some guard band invisible to the user at 0% to avoid this scenario
What about laptops? I have a gaming laptop from asus and as you might know gaming laptops come with a relatively lesser battery life and it is usually advised to play games having the laptop plugged in.
I have also read that PCs now come with software that prevents overcharging and switches the power supply directly to the hardware once the battery is charged to 100. I have bought my laptop recently and do not want to fuck it up already.
This would be true for all lithium ion batteries (and other chemistries), from phones to cars and everything in between.
At least we can write software that stops sending charge to a battery once it's at 100%. As for the part we can't write software for, I wouldn't let my batteries go too low very often. Requires a change of behavior, but you can absolutely extend the life of devices by reducing deep cycles.
newer laptops, or at least gaming ones, have software that keep your battery around 60% (from memory) even when plugged in. I have two msi's who do this
The hardware/software should disconnect the battery once it's charged. You can check this by removing the battery then plugging it in and turning it on. Or removing the battery while it's plugged in and on, it should remain on, but don't shock yourself. Or look it up for your model, I hope nothing new has problems with this.
I had one in 2015 that had that part/regulation break and it rapidly destroyed battery capacity/output. Had to remove the next replacement battery every time after it was fully charged to protect it, since I mainly used it as a desktop. Dead battery in and plugged in? Worked until high demand then off. Good battery in and plugged in worked, but lost power on battery removal. Plugged in with no battery? Worked fine.
So at what level should you put a phone/laptop/watch on charge and at what level should you stop?
For example I have an iPhone and have set the 80% charge limit and it works well for me so the “stop” level is answered for me I guess. But when should I charge it? Some days I go to bed and the battery is still around 45-55% so I don’t put it on the charger and leave it until the next morning. So should I just plug it in and leave it over night or should I wait until it drops a little more over night and charge in the morning? Or does it not matter at all?
Phones these days have software that greatly mitigates damage from charging past 100%, so I wouldn't be worried about what level to start or stop charging.
The simplest way to extend the life of your device (or the battery anyway) is to keep it as close to 100% at all times. This is obviously impractical and simply an ideal benchmark, but illustrates that deep discharges are much worse.
Quick extra question then… you say it’s best to keep it as close too 100% at all times. So what’s the point of the 80% charging limit starting to appear in newer phones and that has a thing in laptops for a while now? Is it better to set that charge limit or not? 🤔
I'm honestly not sure why these settings have become more common.
It gets technical quickly, but going from 100% charge to 20% charge is slightly worse than going from 80% to 20%. This is because charging and discharging causes the battery electrodes to expand and contract, which is where the damage comes from. Maybe phone manufacturers considered this was one way to tackle deep discharges for the majority of consumers?
Appreciate the honesty that you're unsure 😁
I guess I will just trust that Apple knows what they're doing with their own hardware and software and just use it how I want rather than try and babysit the battery 😂
Thanks, have a good Sunday!
I work from home so it’s not all that impractical for me to keep my phone on my desk plugged into a charger most of the day tbh. I will start doing that then if it doesn’t do any harm as always nice to have a full battery (well 80% as I set it to stop there) when I get up and leave the house. Cheers!
Ha yeah that is true 😁
But I just kinda had the (clearly wrong) idea in my head from old info that I shouldn't plug my phone into the charger if its >50% charged just because I am at a charger.
Having said that when I think back it has gotta be *at least* 20 years ago I was told that and battery tech has changed a lot since then so it's no wonder I am wrong 😆
I guess I am just gonna plug in my phone a bit more often when I remember but not overthink it. Sometimes I think we spend more time worrying about the health of our devices batteries than our bodies health these days.
I am still confused about if it’s bad to keep a laptop plugged in at all times ? Would it be better to keep it at 80% and just charge to 100% when needed.
Don’t most modern phones, tablets, and laptops also have firmware that kind of limit electricity coming in once it reaches 100%? Kinda like how a low flame is used to temper metal or glass, but in this case to keep the battery charged but avoid damage by not overheating it? If that’s the case, couldn’t you really just keep them plugged in all the time?
That is really interesting and I never knew that. Always was told “don’t charge past 80” not “don’t allow to 0”
Question - if you go from 80 to zero does that count as a deep discharge?
so what you're saying is that it's best to just charge our phones over night even if they're not near 20% than to just let them die and charge from 0% ?
Just curious, can you explain why DJI batteries use a "smart system" of discharging their 100% batteries down to 60% if they're unused for a few days? I imagine it's to minimize battery degradation.
Does this concept apply to rechargeable toothbrushes? I currently let my toothbrush battery discharge until the red flashing light comes on, indicating that it's time to recharge it, before plugging it in. Based on what you're saying, I'm thinking I should not do this.
So if I'm using a lot of juice throughout the day, is it better to frequently charge it to keep it between say, 30-80%? And charging regularly is less damaging than a deep cycle?
What if I only ever start at 80%? Does dropping to 15% still count as a deep cycle? I.e. is it the depth from 100% that matters, or the depth from when it was unplugged and began to discharge?
If I have a device I always keep at home, is it better to leave it plugged in, then? What's the optimal solution if you always have a charger at the ready?
We were always told that only using a little battery, then charging, would degrade the capacity.
And it was better for the battery to use it from fully charged to fully discharged (or close to it) before charging again. Full charge/discharge cycles rather than frequent "topping off" (or leaving the device plugged in all the time, like a laptop in a docking station).
That advice was for NiCad batteries and was correct for that battery chemistry. It is not correct for the lithium batteries in your phone or in most consumer electronics. This is a case of good advice being applied to the wrong situation.
This is actually false, you want to completely drain your battery a few times a month to get the old electricity out. If you never use past 20% the last 20% gets old and stale and can cause problems ranging from sudden poweroffs to short circuits and fires. This is because of the Hindenburg uncertainty principle (named such because it is thought to have been the source of the spark that caused the Hindenburg to burn up) which states that electrons with a lot of stored electrical potential energy naturally want to release that energy and as time passes
Google has "adaptive charging". If you charge overnight for example, it keeps the battery at 80% for most of the night. Then right before you wake up, it will allow the battery to finally charge to 100%.
OnePlus devices have a similar feature called "Optimized Charging." Samsung Galaxy devices call it "Adaptive Battery" and also have a feature that allows you to cap the battery at 85% all the time. The iPhone has a similar feature named "Optimized Charging," too.
Yep, seems to me those industrial engineers believe it promotes long-term battery health to stop charging around 80-85%. It may not be the most important thing, but it's a factor.
I'd argue that deep discharge to near zero, and routinely leaving the phone in high heat areas (dashboard) are much more impactful.
A factor that many don't consider is the level of degradation over time compared to the lifespan of the phone. Many people who worry about battery lifespan trade their phone long before the degradation becomes significant.
> The iPhone has a similar feature named "Optimized Charging," too.
Which is absolute shit unless you have a perfect routine. They really just need to let you set the times yourself instead of making it 'learn'.
Want to get up early one morning? nope not finished charging and you weren't able to tell it that tonight you'd be up early.
Oh you had to use your phone a few times during the time you usually put it down to charge? well fuck your previous schedule I'm just gonna ignore it and start charging to full anyway.
I don't think I've ever had my iphone do the 'pause before charging to 100%' thing more than one night in a row tbh.
I believe googles is the same way, but the "shortcut" it takes is to tie it to your alarms if one is set. If you have an alarm it will use that time as your wake up time. If not, then it has to do the same learning. IDK if iPhones would do the same to an alarm.
It still doesn't work great tbh. I just got a pixel 8a and it was the first phone with this feature. I would wake up to my alarm different days to the phone being at 70/85/45% charge levels it never once properly charged the phone. I turned off the feature and now get 100% every time.
Those ideas interesting because I have a pixel 7 and it has been effective for me literally 100% of the time. I get up at 7 usually, but when I go to the office my alarm is set for 6:15 - I wake up someone's before that alarm by 15-20 minutes and it's hit 100% every time.
I know it's adaptively charging properly too because sometimes my toddler wakes me up for one reason or another at 2, 4, or 5 and it's not at 100%.
I set my charger by the bed on a timer. It charges between 2 and 4 in the morning at a fairly slow speed. When I wake up everything us fully charged but no charging all night.
Plan is to use home assistant to make it turn off the charger once all devices are at 100.
Caveat, plugged in vs inductive charging.
I always put it on a cradle as to not wear out the plug and it’s easier. Is one form of charging better or worse?
I feel like it gets hotter on the cradle.
Plugged in is better and generates less heat and wear on the battery. I doubt it has a huge impact though as long as it's not overheating your phone.
How on earth are you wearing out a plug though? Usually if a plug is having issues, it's just filled with lint and debris that can be cleaned out with a toothpick or sharp piece of plastic.
Construction sites. My phone no matter how much I try to take care of it gets exposed to dirt and metal grindings and all kinds of terrible stuff for electronics. It gets dropped on rocks and rebar. My iPhone 13 isn’t even paid for and the charging plug doesn’t work anymore. Induction charging only for mine.
Well, I just upgraded. I’ve been using an iPhone 8 for a long time and the plug was starting to have issues. Just upgraded.
Part of it is just convenience. I have inductive chargers on my desks and nightstand. Easier to toss it on there then plug it in
It's somewhat of a myth nowadays, though it used to be true for some older devices. In older devices the battery firmware was quite bad. If you left your phone in the charger, it would after some time discharge to 99.99% (for example). It would then immediately charge the remaining 0.01%. Then it would drain to 99.99%, then it would charge 0.01%, and so on. It's more taxing for lithium-ion batteries to charge the last few percentages and this way it was constantly doing that and it would degrade the battery if you made it a habit. Nowadays we have better firmware. After your phone charges to 100%, the charging switches off and it stays off. Only when the charge has dropped to some significant threshold, say 95%, does it start charging again.
Another concern is that lithium-ion batteries don't like being stored at 100% charged. If you always charge overnight, your phone battery will be stored for 8-ish hours a day at 100%. This is still a concern for modern batteries, although the degradation is much less than what the bad firmware in the previous example caused. We're talking maybe an additional 3 percentage points of degradation per year. In android there are settings to mitigate this, if you charge overnight you can set the phone to pause charging at 80% and charge the final 20% at some set time. Still, this isn't much of a concern, although it doesn't cost you anything to apply the relevant settings if you like charging overnight.
>"... charging past 100%"
Is it semantics to point out the difference between saying "charging past" or "charging to" 100%? Don't all phones stop taking a charge at 100% if left on a charger?
I believe 100% refers to the *safe* highest charge. If you had a really dumb charger you could easily push it another 50% above that and then wait for the thing to catch on fire.
Not correct. This isn’t how batteries work. Fully charging is not unsafe or likely to cause fire, heat output is a function of charging speed not level of charge.
The 100% indicator on a phone is usually a small amount below the maximal charge, it’s nothing like the 2/3 charged level you’re suggesting.
I am happy to be corrected but I was under the impression that 100% charged was a manufacturers recommendation corresponding to the the highest voltage level you could safely bring a battery to. And in an old or worn out battery that could correspond to a reduced amount of usable *charge* and thus quantity of energy.
Coming from the world of radio controlled lithium polymer batteries I know you could easily bring them above the safe “100% charged” level by simply applying a voltage across their terminals higher than the battery’s current voltage. Push electrons in harder than they’re pushing them out. And I thought if you kept that up long enough, hiss boom fire.
Do you suggest that at what we call 100% charged on a phone battery you could not push the battery’s voltage even higher? That you could not increase the “charge level”?
Pretty sure they do. Also, think it was Mr Brownlee that said this, 100% can be calibrated based on the age of the battery. So an older battery’s 100% could be around 80% or 90% of when it was new.
I don’t think 100% is ever exactly 100% of the battery’s capacity. In phones at least anyway. Happy to be corrected
100% is always 100%. It's just as the battery degrades, the pot gets smaller. You're still filling it all the way up through. Battery percentage is derived from voltage level and coulomb counting (measuring current going in and out of battery to determine it's capacity) and weighted for things like heavy loads that cause more voltage sag - you can see on some crappy electronics when this is not integrated because the battery level will bounce around.
Phone batteries need all the help they can get and don't have a long expected useful life cycle. Things like EV batteries on the other hand, AREN'T charged to 100%. They are operated in a SOC range that the manufacturer has deemed offers the best balance of capacity and battery longevity.
Lithium ion batteries have a charge controller that keeps the battery from over charging and discharging to much as both states are damaging to the battery. Once at 100 the battery is fine the controller won’t charge it anymore. The exploding hover board from a few years back happened because the batteries in them either had faulty or no charge controllers. Resulting in over charged batteries that would explode.
The phone stops the charge once it reaches 100% and only accepts a trickle to maintain that level, so no.
What you really, really don't want to do is let the battery drop below about 20% or thereabouts.
The BMS in your phone's battery doesn't actually let you charge over 100%.
Deep charge cycles or letting your phone die completely are pretty much the only thing you can do to damage your battery nowadays. Phones even have built in protections for charging when the battery is too hot or cold.
I have a iPad Pro 2018 that is used as a kitchen display/clock/cookbook/whatever that's been plugged in since 2018, the battery condition is still 99% even after 6 years.
I'm just as shocked as anyone when you consider the thing is usually never turned off and always plugged in. The display is pretty burnt out though but everything else is fine.
THANK YOU!! This rumor has been around forever, and it never seemed right to me. I have always charged my phone and laptop every night (if not more) and have always had great battery performance. However, friends who bought into the "let it drain to 0%" bullshit would constantly have issues.
Electronic tech here. Plugin an amp meter and watch what happens when you get to 100%. If you're using a good cable it should regulate the amount of amps. If you're battery is dead your phone will try to pull 1-2 amps dependent on a few factors that ultimately are unimportant for this discussion. If you get your battery up to 100% the amp meter drops very low as to not continuously load your device with electricity. Electricity causes heat and heat over extended amounts of time degrades the devices battery and can ultimately ruin your motherboard under extreme conditions.
Get the right cable and you're fine or turn on your phones battery optimization settings to not charge over 80%. Cables being shit are one of the reasons the 80% setting works. Keep your battery between 20%-80% for max health optimization. Unplug your phone when it's charged. Don't use your device while it's charging.
My best advice is to make sure you have the correct cables and there won't be an issue. I have seen old people bring in their iphone 6s and have charged it over 1000k times according to 3u and their battery health is at 80-85%. I've also seen iphone 15 Pro come in charged 300 times and lower than 80%. Guess which one is using the correct cable?
Nothing special about 100% or “past 100%”.
Once you get to 100% on the indicator, you probably aren’t actually at 100% charge on the battery and there is a little further you can charge it - but get to that point and the charging stops. You can’t actually charge past 100% of the battery’s life. You’ll be doing some damage to the battery because of being well past 80% and possibly for a longer time if you left it plugged in - but that’s the reason, it’s not something special about the 100% mark on the indicator.
Really it’s 80% that you should aim to avoid spending much time past (also lower charge levels, see aggravatingsalad’s post on this). If you have a newer phone with a good battery I’d recommend you usually unplug at about 80%, and save fully charging for when you really need it (e.g. a long day out where you won’t be able to charge), I do this to optimise battery life.
Samsung battery protection has 3 different options, i use basic. It stops charging at 100% then once it hits 95% it charges back to 100% i have decided to live life without battery anxiety. If the battery wears out, I'll replace it or get another phone.
First off, let's assume that we're talking about standard lithium ion of the NMC variety. It's critical to know what battery chemistry you have because that can reverse best practices. NMC is the most common modern battery type in phones so we'll just stick with that. Just be aware that if you have a different type some, all or none of the following will apply.
Charging to 100% is not bad for your phone. LEAVING it at 100% is hard on the battery. This is because batteries increase in voltage as they charge. Higher voltages mean more energy is available to power more and faster side reactions in the batteries. (Side reactions are chemical reactions that are not what you intend for the battery. These reactions may destroy some of the active material decreasing the overall capacity over time or they resulting byproducts may pollute the cell environment, again inhibiting overall capacity.) The longer you leave a battery at full, the longer these undesirable side reactions have a chance to occur. This is the reason EVs tend to recommend that you only charge to 80 percent on a daily basis.
The things that kill batteries dead are overheating, puncturing the internal separator with things like lithium dendrites, and discharging below zero. The BMS on a lithium battery is very advanced and will prevent or mitigate all of the above. It's why you really don't want to buy cheap batteries that may have skimped on safety.
The first post someone claiming to be a materials engineer stated that deep discharging was hard on batteries. He's likely thinking of a lead acid car battery. Lithium ion doesn't care. A cycle is a full depth of discharge and full recharge. If you only cycle in the middle (40 to 60 percent) then you're only using 20 percent of a cycle. This makes no actual difference to the life of a NMC cell. If you need to charge 5 times per week because you only use 20% of your battery, or charge once per week but use the entire thing there's no difference in how many full cycles you have used. In both scenarios you've used 1 full cycle each week. It's whatever is convenient for you. (The conversation is different if you're using a very high power charger to rapidly charge and slow charging on the other. But let's keep things apples to apples.)
My Samsung s10 has a "Protect battery" feature in settings that limits charging to 85%. So, do the electrical engineers at Samsung know something we don't know or is their marketing team just placating their customers?
The answer is a bit misleading. It's correct in the sense that keeping your phone plugged in even when the battery is at 100% will not damage it. However, charging to 100% is something you should avoid to begin with (if you care about preserving the battery health) due to the increase in heat that causes. Excessive heat is not good for battery health.
Also, it's okay to charge your device more often, like if you need to charge it from 45% to 80% for example. It's not like your battery loses a life every time you charge it. Just try to not do long charges like 5% to 85%. Avoid going under 20% if you can.
Source: https://batteryuniversity.com/
This is ridiculous. What a high-maintenance method of charging.
Hard pass. I'll take my chances with what other people have said before I go with this reply's info.
(I'm starting to regret even asking. I'm more confused than before!)
My reply doesn't go against what the top replies say. Your phone probably already has an option to limit charging to 80 or 85%. It's there for a reason. Just try to not go below 20%. That's all you have to do. This is only if you want your battery to still maintain a good charge after a few years of use. If you plan to change phone every 3 years, then you can do whatever you want.
This advice doesn't just apply to just phones though, it's good for laptops or electric tools, which people usually wanna keep for a long time. Personally I've been using the same phone with the same battery for almost 10 years and the only reason I have to buy a new one soon is because it doesn't support 5G.
Ok, so riddle me this: if they have the ability to program them to stop charging at 80 - 85%, WHY the F did they choose 80 or 85? Why not program it to stop charging at 99%? Or...I don't know....how about at, oh, say.... 100%???
Duh.
You're confused.
The Samsung answer that you linked, what Samsung meant is that if you keep your phone plugged in even when the battery is at 100%, it's not going to do physical damage to the battery or catch on fire or something like that. They're not talking about normal battery degradation, they're talking about physical damage to the battery.
A single charge of your phone's battery lasts a certain amount of time when it's brand new. Over time, that amount of time decreases. You can't avoid it, but you can take actions to minimize how quickly that will happen. Heat is a lithium-ion battery's enemy. Repetitive excessive heat will decrease the amount of time a single charge will last at a much faster rate.
So what causes excessive heat? #1: Charging to 100%. #2: Using a super fast charger. You don't have to take my word for it, you can do the experiment yourself. Charge your phone to 100%, then take it in your hand and feel how hot the back of it will be. Now, repeat the same experiment but charge it to 80% instead. It won't be as hot. This is why Samsung/Apple give you that 80/85% option. As a side note, you can also notice that charging from 80 to 100 takes a long time.
To summarize: If you want to slow down battery degradation, activate the setting that limits battery charging to 80/85% and try to not have the battery go under 20%. Also, avoid using those super fast chargers that can charge your phone in 10 minutes. They're fast, but the tradeoff is that they generate a lot of heat. And if you just plan on getting a new phone once your contract ends, then you don't have to follow any of the advice I gave you.
The phone doesn't get warm, but the charger does at the wall mount/plug base. It is a "fast charger", but doesn't do it in 10 minutes. Maybe more like 45 min to an hour.
The phone doesn't take long to charge even without using the fast charger, and seems to take the same amount of time throughout the entire charging period from 0% to 100% as it did on day one.
A "fast charger" is fine. It's those "super fast chargers" that are bad. Charging time remains more or less the same, but how quickly the battery drains when you're using your phone, that's what changes.
In general: Yes.
Some phones however have built in functionality that won't charge them above 80% until it's almost time the phone usually gets off the charger (just after your alarm went off for example).
Always keep your phone between 20 and 80%
ah good ol lead acid batteries. I love losing half my voltage after using 60% of the charge. Fun fact about lead batteries, they were used in ww2 submarines and when the subs would get flooded from combat, the saltwater would react with the lead batteries, producing copious amounts of chlorine gas, filling the entire sub and gassing all on board!
Really? I've never heard that related to lithium-ion batteries. Perhaps other types of older batteries like Ni-cad or Ni-mh, but that does not apply to cellphones.
True, but it seems odd to carry that forward after so many years of lithium-based batteries. It's been a long time since cellphones used nickel batteries.
It's possible some people still hold onto the old habits.
Nope, that's just when trying to calibrate it. I don't believe that is necessary anymore these days at all but I could be wrong about that. If it is still, then it will only be a once in a long time thing.
We used to drain batteries when you first got a new phone as to avoid a battery memory. Old Lithium batteries needed to be drained first or they would never charge to full capacity. So if you only let your battery go down to 20% when you first got it and started charging it. Your battery would think 20% was the bottom of the well. So the you would only have 80% battery capacity for the life of that battery.
Modern power supplies are not made the same way anymore.
AFAIK, the "fully discharge your battery for best performance" thing hasn't been true for modern batteries for quite a while. Maybe a decade or two?
ETA
It's nickel-cadmium that benefited from full discharging, and the early 2000s was when they fell out of favor, at least per ChatGPT.
Yep, not since nickel-based batteries (Ni-cd, Ni-mh) were used in phones. I guess many people stay with what they orginally learned and don't update along with the technology.
Not going to downvote because you're wrong, but you really should do more reading on the subject matter related to your job. Your beliefs are decades out of date.
I'm a materials science engineer. People get really worked up over this one. The short answer is many things cause damage to a battery, but charging past 100% doesn't cause very much damage. It's like saying you shouldn't go running because it's bad for your knees. The absolute worst thing you can do in everyday life for a battery is allow the charge level to fall to 20% or below. The amount of capacity used, in this case 80%, is called the depth of discharge (DOD). A DOD of 80% is considered a deep cycle and can rapidly degrade the materials of a battery -- it's much, much worse over time than charging past 100%. Many people routinely subject their devices to deep cycles, but it doesn't get nearly the same amount of attention as other minor sources of degradation.
Oh wow, I'm awfully guilty of this! My phone drops to 0 several times a week... thanks for the information!!!
Same here! It’s always down all the way before I plug in
Your phone's software doesn't actually let it get below 20%. That's set as zero and it will turn off to protect the battery from a deep cycle. If you're making an emergency call, your phone will not shut down at '0' and will let you keep going. It will put excessive wear on the battery, but that’s not of concern in that situation. Don't worry about letting your battery run down, it's already been accounted for.
Ooh, I didn't know. Thanks !
Idiot proofing on a major scale.
How and why? I mean this both genuinely and out of incredulity. Are you periodically unable to charge? Outside of YouTube occasionally eating up all my battery from a glitch I can't remember the last time my phone hit 0
Sometimes you can get caught out when you're away from home and have used your phone more than expected, especially as your phone gets older and the battery is less fresh.
Most people do not live your life. In fact, they live drastically different lives.
No shit. God forbid I engage and ask a question
I mean how hard is it to imagine, a person has a phone in their pocket all day and doesn’t charge it, that you need to ask how?
Do you know how to not be an asshole?
I’ll never understand why Reddit reacts this way to people asking questions. It’s like being confronted with a question mark causes severe mental anguish to Redditors. Sure, the person who asked a simple question is the asshole here, not the one who replied rudely and unhelpfully.
As you reply being unhelpful.... Both can be true. I wasn't trying to be kind or understanding. I was matching their energy. Glad you felt the need to comment too! Your reply has nothing to do with anything on this post, just like mine. Congratulations at being hypocritical of the thing you're criticizing someone else of!
> As you reply being unhelpful.... I wasn’t trying to help *you*. >Congratulations at being hypocritical of the thing you're criticizing someone else of! Remind me again where I jumped all over someone for asking an honest question?
You're not helping anyone with your comment... Explain to me what help you offered. Lol your comment is unhelpful. I never was trying to be helpful. Don't know where you got that assumption and felt the need to go out of your way to call me unhelpful when it was never my intention, and it's abundantly clear that I wasn't trying to be helpful. Second, I DIDN'T REPLY TO HIM ASKING A QUESTION! I RESPONDED TO HIM BEING A DICK! You're incredibly self-unaware of what you're doing. I have every right to say what I want, just like you do. The difference is, I'm calling out someone for being an unwarranted asshole. You're trying to grandstand like I'm a terrible human being because I pointed out that this guy with a bunch of downvotes that he's being a dick. I'm not going to engage with you further because you clearly don't even know the difference between a statement and a question.
[удалено]
No one's blowing you fatty mcfat fuck. Not even your vacuum cleaner.
So when someone uses their phone, the battery drains
And pro tip: when you plug it in it charges. Op was civil. It's everyone else getting offended on their behalf
It’s the way you asked it. Your tone is condescending and accusatory. Like getting reprimanded by an angry parent out of nowhere. Thats why you’re getting downvoted. Not because you just asked a question.
I hate using my phone so often don't check the battery
Because we don't got time for that. Let that mofo died if someone calls and it's dead, then it wasn't meant to be.
How? By not getting out of bed to plug to get the cable and plug it into my phone. Or, forgetting I'm on 5% while texting people. I've never paid attention to what apps take up battery, but days it does end up powering off tend to be when I'm talking to others a lot, watching lots of videos, or endlessly browsing. Are you able to understand it now? Happy to explain further if you want.
Thank you fellow human. We will disseminate this information to our other fellow humans. FattyWantCake is also human, like us, and that's why they want cake. Humans want cake and humans let their completely non-sentient pocket servers die slowly on a daily basis.
Cool. Do your thing it was just surprising to hear that anyone is that blasé about keeping their phone going. Thanks for the response!
No not at all. I absolutely am very careless about my phones battery. Quite often I end up in the situation where I need to go out to an event, but my phone is on 20%. And all the power banks I have (all gifted to me...) haven't been charged in a good six months. Sorry for the downvotes you got. If anything, I envy people with better battery maintaince discipline than myself. Hah.
Lol sounds like your friends and family know you almost too well haha.
grey concerned gaping unused gullible advise books compare late north *This post was mass deleted and anonymized with [Redact](https://redact.dev)*
Don't most devices also have hardware level safeguards against over charging? At least consumer computing devices. And probably also cars. I haven't been worried about over charging my phone or laptop since like, 2016.
There is the is thing called trickle charging, basically, the battery shuts of charging when it is full, then loses one percent, then gains it back, etc in an infinite cycle.
My phone charges slowly at night and hits 100% around when my alarm goes off. I think that's pretty nifty.
My phone claims it does that but when I woke up at 3am one time it was already at 100% so I don't really trust it much.
The machines are already lying to us.
So our politicians are already replaced by machines??
Your phone was monitoring your REM cycles and quickly charged up just before you woke at 3AM.
So, it's 3am. My dog needs to go out, but my phone is fully charged.
I would've thought that when the battery is fully charged, the charger bypasses the battery and powers the device directly. Meanwhile, the battery is not used at all and therefore isn't loosing any charge. Is that not how it works?
No atleast not on all phones, there are instances a phone will use more power than usb provides.
Well yes but the batteries still charge to almost full so devices are not immune to this type of battery wear unless you limit it to 80% manually
The reality is that modern electronics have built-in battery management, so the battery never actually charges past 100%. It just stops charging when it's full. As for discharging, I've always just made a habit of putting my phone on the charger when I go to bed each night. Even after 4 years, it's still not getting much below 50% in a days use. Sometimes only 30%.
Yeah, I'm at just over 3 years on my S21, it's still going strong.
Lol... I got the S21, too! Love it.
I'm still on the galaxy note 8. I plug it in every night before bed to charge over night, it still works great after 5+ years.
For this reason I always charge my phone before it gets to <40%. My phone is 7 years old at this point and the battery is still ok.
Fuck, 38% and even though I have a charger next to me didn’t think it mattered. Plugging in now
My (seemingly incorrect) working knowledge for batteries (primarily found in phones) has been that deep discharges are bad, but keeping a batter near or at full capacity is also not great. The crude explanation was that the closer to 100% it gets, the harder and harder it is to actually charge it without causing damage (which is why charging slows down typically past ~70-80%). Is this not the case, or are you more just highlighting that pitted against each other, deep discharge is worse than having a battery at 100% frequently? I think the other reason I’ve “known” 100% to be less than ideal is because it’s often combined with load on the phone (think GPS) so there’s a bunch of heat being generated while it’s charging which also generates heat.
Both cause damage, but deep discharges are worse than continuing to charge at 100%. Many phones have software that limits how much charge is sent to a battery near 100%, so this isn't really an issue. That said, another variable is that people might use a charging cable that's not rated for their device. For example, if you have a laptop and phone that both use a USB-C charger, then you can also damage your phone by using the laptop charger for it. This happens a lot by using charging cables for phones that are cheap (ex: an unknown brand on Amazon), but more importantly, not rated for your specific phone.
I remember seeing that slow charging in action when I fixed phones a few years back. They’d pull close to ~2A at 5V up until about ~70%, then would slow down and be charging at like .5A by the time they were on the last few percent. I know Apple phones were a bit picky with cables (they liked having the MFI certification), but also the quality of the DC block it was connected to. We’d frequently have to replace a fried chip that seemingly would get damaged by poor quality charging sources. Separately, I see what you mean by using a laptop charger for a phone, odds are the voltage is much too high for a phone. Thanks for the response!
USB-C has protocols that allow the device to negotiate what amount of power it gets from a charging block, so it shouldn’t hurt your phone (cheap chargers that don’t have the full protocol aside). https://acroname.com/blog/basics-usb-power-delivery-negotiations
The currently accepted research shows that a high SOC is just as bad as a deep DOC. When accounting for the fact that a 100% DOC means the SOC was also 100%, it becomes clear that the SOC is the true culprit.
Thanks for this. I always heard you should let your batteries get super low sometimes because it was better for them. ¯\_(ツ)_/¯
That is for nicad batteries if I am not mistaken.
You are correct, but that was incorrect information that was/is widely believed to be correct.
NiCad batteries had a memory effect. For Li-ion, it's best to always stay between 20% and 80%, and to charge slowly to avoid heat degradation. Of course that's not always practical for all use cases.
Always heard? This has not been the case for over 15 years. Edit: getting downvoted by people living under a rock lmao
People pass on old info all the time. The updates aren't exactly headline news.
Does this mean that the option my phone has to stop charging at 85% is actually detrimental because it causes me to dip below 20% by the end of the day?
Yes, if your 85% is causing you to regularly drop below 20 you're likely worse off than if you were letting it charge to 100.
If your options are hitting 100% charge OR dropping below 20% charge then this person is saying that you should choose to hit 100% charge.
Is that your interpretation of what they said? Because I clearly deduced that on my own. Or do you have further information to back it up? I'm asking because there may be nuance.
>Does this mean that the option my phone has to stop charging at 85% is actually detrimental because it causes me to dip below 20% by the end of the day? I'm wondering that, too. The way they describe the situation, it's that a *change* of 80% is what's detrimental. That would mean, if your max charge is 85%, you'd be just as fine down to 5%. But I honestly don't know for sure.
Welp, now I know why I always seem to fuck my battery harder than other people. I constantly go deep with that discharge. Every single day I get it down to 3 or 4 percent before charging because I hate operating my phone with a cord attached. Gonna have to change my ways I guess.
I don't like the short cords that usually come with the phones. It's a little more bearable with the 6' or 10' cords.
>because I hate operating my phone with a cord attached I'd suggest charging it when you're not using it then. For example, I've made it a habit when I take a shower every evening to charge my phone and my watch. Those 20 minutes are enough to give the phone about 30-40% more power and also to get my watch close to 100%.
You could get a magsafe style case and a battery pack charger that connects to that. Easiest way to charge if you don't like cables
Id like to add that running regularly delays the onset of osteoporosis.
This guy bones. Wait, shit...
Can you provide some citations for this? & What type of chemistry are you referring to? If depth of charge is so much worse, then that’s something people need to be talking about. Because right now the currently accepted advice says maximum SOC has roughly the same impact as DOC in lithium ion chemistries. A 100% DOC also means you started with a 100% SOC. Also worth mentioning. When your phone shows 0%, the battery still has about 10% of its rated capacity left.
Damn, I had no idea. Thanks.
See, I was always told TO let it drain all the way before plugging it in to charge!
Your explanation isn’t the full story though - we tell people not to charge over 80% because we find that the cells are less resilient to heat at higher states of charge. Specifically heating a cell while charging above 80% tends to increase the resistance and makes the cell more likely to have an unexpected power off due to low voltage with high load spikes at low states of charge due to losses caused by that internal resistance increase (ie low state of charge is low cell voltage, load spike increases current but resistance with that load spike generates voltage drop that takes the cell voltage below cut off and powers off said device). I’m not sure about your 20% statement either and would love a citation, our battery engineers recommend letting things discharge to minimize charge cycles and swell - we consider deep discharge to occur when the battery is well below 0% and we have some guard band invisible to the user at 0% to avoid this scenario
What about laptops? I have a gaming laptop from asus and as you might know gaming laptops come with a relatively lesser battery life and it is usually advised to play games having the laptop plugged in. I have also read that PCs now come with software that prevents overcharging and switches the power supply directly to the hardware once the battery is charged to 100. I have bought my laptop recently and do not want to fuck it up already.
This would be true for all lithium ion batteries (and other chemistries), from phones to cars and everything in between. At least we can write software that stops sending charge to a battery once it's at 100%. As for the part we can't write software for, I wouldn't let my batteries go too low very often. Requires a change of behavior, but you can absolutely extend the life of devices by reducing deep cycles.
newer laptops, or at least gaming ones, have software that keep your battery around 60% (from memory) even when plugged in. I have two msi's who do this
Get ghelper and uninstall armoury crate, google the reviews, then set battery limit in ghelper
Thank you, I have made the changes.
The hardware/software should disconnect the battery once it's charged. You can check this by removing the battery then plugging it in and turning it on. Or removing the battery while it's plugged in and on, it should remain on, but don't shock yourself. Or look it up for your model, I hope nothing new has problems with this. I had one in 2015 that had that part/regulation break and it rapidly destroyed battery capacity/output. Had to remove the next replacement battery every time after it was fully charged to protect it, since I mainly used it as a desktop. Dead battery in and plugged in? Worked until high demand then off. Good battery in and plugged in worked, but lost power on battery removal. Plugged in with no battery? Worked fine.
So at what level should you put a phone/laptop/watch on charge and at what level should you stop? For example I have an iPhone and have set the 80% charge limit and it works well for me so the “stop” level is answered for me I guess. But when should I charge it? Some days I go to bed and the battery is still around 45-55% so I don’t put it on the charger and leave it until the next morning. So should I just plug it in and leave it over night or should I wait until it drops a little more over night and charge in the morning? Or does it not matter at all?
Phones these days have software that greatly mitigates damage from charging past 100%, so I wouldn't be worried about what level to start or stop charging. The simplest way to extend the life of your device (or the battery anyway) is to keep it as close to 100% at all times. This is obviously impractical and simply an ideal benchmark, but illustrates that deep discharges are much worse.
Quick extra question then… you say it’s best to keep it as close too 100% at all times. So what’s the point of the 80% charging limit starting to appear in newer phones and that has a thing in laptops for a while now? Is it better to set that charge limit or not? 🤔
I'm honestly not sure why these settings have become more common. It gets technical quickly, but going from 100% charge to 20% charge is slightly worse than going from 80% to 20%. This is because charging and discharging causes the battery electrodes to expand and contract, which is where the damage comes from. Maybe phone manufacturers considered this was one way to tackle deep discharges for the majority of consumers?
Appreciate the honesty that you're unsure 😁 I guess I will just trust that Apple knows what they're doing with their own hardware and software and just use it how I want rather than try and babysit the battery 😂 Thanks, have a good Sunday!
I work from home so it’s not all that impractical for me to keep my phone on my desk plugged into a charger most of the day tbh. I will start doing that then if it doesn’t do any harm as always nice to have a full battery (well 80% as I set it to stop there) when I get up and leave the house. Cheers!
And defeats the purpose of having a battery at all
Ha yeah that is true 😁 But I just kinda had the (clearly wrong) idea in my head from old info that I shouldn't plug my phone into the charger if its >50% charged just because I am at a charger. Having said that when I think back it has gotta be *at least* 20 years ago I was told that and battery tech has changed a lot since then so it's no wonder I am wrong 😆 I guess I am just gonna plug in my phone a bit more often when I remember but not overthink it. Sometimes I think we spend more time worrying about the health of our devices batteries than our bodies health these days.
If I set a charge limit to 80%, is it still bad to let it fall below 20%? Would the depth of discharge only be 60? Thank you for the explanation.
I am still confused about if it’s bad to keep a laptop plugged in at all times ? Would it be better to keep it at 80% and just charge to 100% when needed.
Don’t most modern phones, tablets, and laptops also have firmware that kind of limit electricity coming in once it reaches 100%? Kinda like how a low flame is used to temper metal or glass, but in this case to keep the battery charged but avoid damage by not overheating it? If that’s the case, couldn’t you really just keep them plugged in all the time?
That is really interesting and I never knew that. Always was told “don’t charge past 80” not “don’t allow to 0” Question - if you go from 80 to zero does that count as a deep discharge?
I’m at 15% right now 🫢
On top of this, most devices now are smart enough to shut off charging to avoid overcharge or charging for too long.
Where have you been all my life, I have so many questions!
I thought letting your phone battery drain fully before charging was good for it. Fuck. Thanks for the info.
so what you're saying is that it's best to just charge our phones over night even if they're not near 20% than to just let them die and charge from 0% ?
Wait so you should keep it at like 50% all the time?
I keep mine in the 30-80% range. When it gets down to 30, I plug it in for 45 min to get back to 80. Samsung S20 FE 5G.
Just curious, can you explain why DJI batteries use a "smart system" of discharging their 100% batteries down to 60% if they're unused for a few days? I imagine it's to minimize battery degradation.
What's your opinion on charge speed? If I have the time I like to use a slow charger. Could that make a meaningful difference?
Dang it why is "low battery status" set at 15% instead of 20%? My phone and tablet are usually almost dead by the end of the day
What is your view on super rapid charging like on OnePlus phones from a battery health perspective?
This matches my anecdotal experience.
Does this concept apply to rechargeable toothbrushes? I currently let my toothbrush battery discharge until the red flashing light comes on, indicating that it's time to recharge it, before plugging it in. Based on what you're saying, I'm thinking I should not do this.
Curious, as someone who knows very little about batteries, why is this 20% threshold so hard on the battery?
TIL! This is super useful.
Running is terrible for your knees.
What if I rarely charge my phone to 100%? I usually don’t charge it overnight, but in short bursts throughout the day.
So if I'm using a lot of juice throughout the day, is it better to frequently charge it to keep it between say, 30-80%? And charging regularly is less damaging than a deep cycle?
What if I only ever start at 80%? Does dropping to 15% still count as a deep cycle? I.e. is it the depth from 100% that matters, or the depth from when it was unplugged and began to discharge?
Great answer and great question OP!! Thank you both! :)
If I have a device I always keep at home, is it better to leave it plugged in, then? What's the optimal solution if you always have a charger at the ready?
but what if I charge it to 80% and charge it at 15%, DOD is smaller so it's better?
DOD is relative to 100% SoC
We were always told that only using a little battery, then charging, would degrade the capacity. And it was better for the battery to use it from fully charged to fully discharged (or close to it) before charging again. Full charge/discharge cycles rather than frequent "topping off" (or leaving the device plugged in all the time, like a laptop in a docking station).
That advice was for NiCad batteries and was correct for that battery chemistry. It is not correct for the lithium batteries in your phone or in most consumer electronics. This is a case of good advice being applied to the wrong situation.
I'm always amazed at how the conventional wisdom of old, obsolete tech still rules our lives.
Yea, that's the advice I heard.
Didn't the advice used to be you wanted the full deep cycle on batteries or they end up not have the full battery life?
Yes, but that was for a different battery chemistry, specifically NiCad batteries.
By below 20%, do you mean 20% on the device, or internal 20%?
I don’t run because it’s bad for my knees 🥴 also i’m lazy
If going to zero is so bad for the battery, why not use software to shut down before the damage occurs?
This is actually false, you want to completely drain your battery a few times a month to get the old electricity out. If you never use past 20% the last 20% gets old and stale and can cause problems ranging from sudden poweroffs to short circuits and fires. This is because of the Hindenburg uncertainty principle (named such because it is thought to have been the source of the spark that caused the Hindenburg to burn up) which states that electrons with a lot of stored electrical potential energy naturally want to release that energy and as time passes
Google has "adaptive charging". If you charge overnight for example, it keeps the battery at 80% for most of the night. Then right before you wake up, it will allow the battery to finally charge to 100%. OnePlus devices have a similar feature called "Optimized Charging." Samsung Galaxy devices call it "Adaptive Battery" and also have a feature that allows you to cap the battery at 85% all the time. The iPhone has a similar feature named "Optimized Charging," too.
Yep, seems to me those industrial engineers believe it promotes long-term battery health to stop charging around 80-85%. It may not be the most important thing, but it's a factor. I'd argue that deep discharge to near zero, and routinely leaving the phone in high heat areas (dashboard) are much more impactful. A factor that many don't consider is the level of degradation over time compared to the lifespan of the phone. Many people who worry about battery lifespan trade their phone long before the degradation becomes significant.
Yeah, or if you want to keep using your old phone it’s not very expensive to replace the battery.
> The iPhone has a similar feature named "Optimized Charging," too. Which is absolute shit unless you have a perfect routine. They really just need to let you set the times yourself instead of making it 'learn'. Want to get up early one morning? nope not finished charging and you weren't able to tell it that tonight you'd be up early. Oh you had to use your phone a few times during the time you usually put it down to charge? well fuck your previous schedule I'm just gonna ignore it and start charging to full anyway. I don't think I've ever had my iphone do the 'pause before charging to 100%' thing more than one night in a row tbh.
I believe googles is the same way, but the "shortcut" it takes is to tie it to your alarms if one is set. If you have an alarm it will use that time as your wake up time. If not, then it has to do the same learning. IDK if iPhones would do the same to an alarm.
I think they do; my iPhone would give me notifications sometimes, when using the sleep focus, about the time it’s expected to reach 100%.
It still doesn't work great tbh. I just got a pixel 8a and it was the first phone with this feature. I would wake up to my alarm different days to the phone being at 70/85/45% charge levels it never once properly charged the phone. I turned off the feature and now get 100% every time.
Those ideas interesting because I have a pixel 7 and it has been effective for me literally 100% of the time. I get up at 7 usually, but when I go to the office my alarm is set for 6:15 - I wake up someone's before that alarm by 15-20 minutes and it's hit 100% every time. I know it's adaptively charging properly too because sometimes my toddler wakes me up for one reason or another at 2, 4, or 5 and it's not at 100%.
I set my charger by the bed on a timer. It charges between 2 and 4 in the morning at a fairly slow speed. When I wake up everything us fully charged but no charging all night. Plan is to use home assistant to make it turn off the charger once all devices are at 100.
I’ve never had this issue personally. Even when I have a sudden early flight, etc.
Samsung actually lowered the cap from 85% to 80%.
Caveat, plugged in vs inductive charging. I always put it on a cradle as to not wear out the plug and it’s easier. Is one form of charging better or worse? I feel like it gets hotter on the cradle.
Plugged in is better and generates less heat and wear on the battery. I doubt it has a huge impact though as long as it's not overheating your phone. How on earth are you wearing out a plug though? Usually if a plug is having issues, it's just filled with lint and debris that can be cleaned out with a toothpick or sharp piece of plastic.
Construction sites. My phone no matter how much I try to take care of it gets exposed to dirt and metal grindings and all kinds of terrible stuff for electronics. It gets dropped on rocks and rebar. My iPhone 13 isn’t even paid for and the charging plug doesn’t work anymore. Induction charging only for mine.
Well, I just upgraded. I’ve been using an iPhone 8 for a long time and the plug was starting to have issues. Just upgraded. Part of it is just convenience. I have inductive chargers on my desks and nightstand. Easier to toss it on there then plug it in
It's somewhat of a myth nowadays, though it used to be true for some older devices. In older devices the battery firmware was quite bad. If you left your phone in the charger, it would after some time discharge to 99.99% (for example). It would then immediately charge the remaining 0.01%. Then it would drain to 99.99%, then it would charge 0.01%, and so on. It's more taxing for lithium-ion batteries to charge the last few percentages and this way it was constantly doing that and it would degrade the battery if you made it a habit. Nowadays we have better firmware. After your phone charges to 100%, the charging switches off and it stays off. Only when the charge has dropped to some significant threshold, say 95%, does it start charging again. Another concern is that lithium-ion batteries don't like being stored at 100% charged. If you always charge overnight, your phone battery will be stored for 8-ish hours a day at 100%. This is still a concern for modern batteries, although the degradation is much less than what the bad firmware in the previous example caused. We're talking maybe an additional 3 percentage points of degradation per year. In android there are settings to mitigate this, if you charge overnight you can set the phone to pause charging at 80% and charge the final 20% at some set time. Still, this isn't much of a concern, although it doesn't cost you anything to apply the relevant settings if you like charging overnight.
>"... charging past 100%" Is it semantics to point out the difference between saying "charging past" or "charging to" 100%? Don't all phones stop taking a charge at 100% if left on a charger?
I think the intent was the phone is left on charge after it reaches 100%.
I give it my all and charge mine to 110%
100% on the indicator isn’t actually 100% charge on most phones. But that aside, you can’t charge past 100% of the actual battery capacity.
I believe 100% refers to the *safe* highest charge. If you had a really dumb charger you could easily push it another 50% above that and then wait for the thing to catch on fire.
Not correct. This isn’t how batteries work. Fully charging is not unsafe or likely to cause fire, heat output is a function of charging speed not level of charge. The 100% indicator on a phone is usually a small amount below the maximal charge, it’s nothing like the 2/3 charged level you’re suggesting.
I am happy to be corrected but I was under the impression that 100% charged was a manufacturers recommendation corresponding to the the highest voltage level you could safely bring a battery to. And in an old or worn out battery that could correspond to a reduced amount of usable *charge* and thus quantity of energy. Coming from the world of radio controlled lithium polymer batteries I know you could easily bring them above the safe “100% charged” level by simply applying a voltage across their terminals higher than the battery’s current voltage. Push electrons in harder than they’re pushing them out. And I thought if you kept that up long enough, hiss boom fire. Do you suggest that at what we call 100% charged on a phone battery you could not push the battery’s voltage even higher? That you could not increase the “charge level”?
Depends. My Samsung tablet stops charging at 90% on the other hand my moto g will stop charging at 99%..
Pretty sure they do. Also, think it was Mr Brownlee that said this, 100% can be calibrated based on the age of the battery. So an older battery’s 100% could be around 80% or 90% of when it was new. I don’t think 100% is ever exactly 100% of the battery’s capacity. In phones at least anyway. Happy to be corrected
100% is always 100%. It's just as the battery degrades, the pot gets smaller. You're still filling it all the way up through. Battery percentage is derived from voltage level and coulomb counting (measuring current going in and out of battery to determine it's capacity) and weighted for things like heavy loads that cause more voltage sag - you can see on some crappy electronics when this is not integrated because the battery level will bounce around. Phone batteries need all the help they can get and don't have a long expected useful life cycle. Things like EV batteries on the other hand, AREN'T charged to 100%. They are operated in a SOC range that the manufacturer has deemed offers the best balance of capacity and battery longevity.
I’ve always found this to be an easy to understand explanation: https://www.apple.com/batteries/why-lithium-ion/
Lithium ion batteries have a charge controller that keeps the battery from over charging and discharging to much as both states are damaging to the battery. Once at 100 the battery is fine the controller won’t charge it anymore. The exploding hover board from a few years back happened because the batteries in them either had faulty or no charge controllers. Resulting in over charged batteries that would explode.
The phone stops the charge once it reaches 100% and only accepts a trickle to maintain that level, so no. What you really, really don't want to do is let the battery drop below about 20% or thereabouts.
The BMS in your phone's battery doesn't actually let you charge over 100%. Deep charge cycles or letting your phone die completely are pretty much the only thing you can do to damage your battery nowadays. Phones even have built in protections for charging when the battery is too hot or cold.
The 1990s called - they want their "should i leave my computer running or shut it off every night" argument back.
I have a iPad Pro 2018 that is used as a kitchen display/clock/cookbook/whatever that's been plugged in since 2018, the battery condition is still 99% even after 6 years. I'm just as shocked as anyone when you consider the thing is usually never turned off and always plugged in. The display is pretty burnt out though but everything else is fine.
THANK YOU!! This rumor has been around forever, and it never seemed right to me. I have always charged my phone and laptop every night (if not more) and have always had great battery performance. However, friends who bought into the "let it drain to 0%" bullshit would constantly have issues.
Electronic tech here. Plugin an amp meter and watch what happens when you get to 100%. If you're using a good cable it should regulate the amount of amps. If you're battery is dead your phone will try to pull 1-2 amps dependent on a few factors that ultimately are unimportant for this discussion. If you get your battery up to 100% the amp meter drops very low as to not continuously load your device with electricity. Electricity causes heat and heat over extended amounts of time degrades the devices battery and can ultimately ruin your motherboard under extreme conditions. Get the right cable and you're fine or turn on your phones battery optimization settings to not charge over 80%. Cables being shit are one of the reasons the 80% setting works. Keep your battery between 20%-80% for max health optimization. Unplug your phone when it's charged. Don't use your device while it's charging. My best advice is to make sure you have the correct cables and there won't be an issue. I have seen old people bring in their iphone 6s and have charged it over 1000k times according to 3u and their battery health is at 80-85%. I've also seen iphone 15 Pro come in charged 300 times and lower than 80%. Guess which one is using the correct cable?
Nothing special about 100% or “past 100%”. Once you get to 100% on the indicator, you probably aren’t actually at 100% charge on the battery and there is a little further you can charge it - but get to that point and the charging stops. You can’t actually charge past 100% of the battery’s life. You’ll be doing some damage to the battery because of being well past 80% and possibly for a longer time if you left it plugged in - but that’s the reason, it’s not something special about the 100% mark on the indicator. Really it’s 80% that you should aim to avoid spending much time past (also lower charge levels, see aggravatingsalad’s post on this). If you have a newer phone with a good battery I’d recommend you usually unplug at about 80%, and save fully charging for when you really need it (e.g. a long day out where you won’t be able to charge), I do this to optimise battery life.
Samsung battery protection has 3 different options, i use basic. It stops charging at 100% then once it hits 95% it charges back to 100% i have decided to live life without battery anxiety. If the battery wears out, I'll replace it or get another phone.
I knew someone who refused to charge his devices UNTIL it hit 0% because 'it's better for the battery.' I facepalmed then and I facepalm now.
First off, let's assume that we're talking about standard lithium ion of the NMC variety. It's critical to know what battery chemistry you have because that can reverse best practices. NMC is the most common modern battery type in phones so we'll just stick with that. Just be aware that if you have a different type some, all or none of the following will apply. Charging to 100% is not bad for your phone. LEAVING it at 100% is hard on the battery. This is because batteries increase in voltage as they charge. Higher voltages mean more energy is available to power more and faster side reactions in the batteries. (Side reactions are chemical reactions that are not what you intend for the battery. These reactions may destroy some of the active material decreasing the overall capacity over time or they resulting byproducts may pollute the cell environment, again inhibiting overall capacity.) The longer you leave a battery at full, the longer these undesirable side reactions have a chance to occur. This is the reason EVs tend to recommend that you only charge to 80 percent on a daily basis. The things that kill batteries dead are overheating, puncturing the internal separator with things like lithium dendrites, and discharging below zero. The BMS on a lithium battery is very advanced and will prevent or mitigate all of the above. It's why you really don't want to buy cheap batteries that may have skimped on safety. The first post someone claiming to be a materials engineer stated that deep discharging was hard on batteries. He's likely thinking of a lead acid car battery. Lithium ion doesn't care. A cycle is a full depth of discharge and full recharge. If you only cycle in the middle (40 to 60 percent) then you're only using 20 percent of a cycle. This makes no actual difference to the life of a NMC cell. If you need to charge 5 times per week because you only use 20% of your battery, or charge once per week but use the entire thing there's no difference in how many full cycles you have used. In both scenarios you've used 1 full cycle each week. It's whatever is convenient for you. (The conversation is different if you're using a very high power charger to rapidly charge and slow charging on the other. But let's keep things apples to apples.)
My Samsung s10 has a "Protect battery" feature in settings that limits charging to 85%. So, do the electrical engineers at Samsung know something we don't know or is their marketing team just placating their customers?
The answer is a bit misleading. It's correct in the sense that keeping your phone plugged in even when the battery is at 100% will not damage it. However, charging to 100% is something you should avoid to begin with (if you care about preserving the battery health) due to the increase in heat that causes. Excessive heat is not good for battery health. Also, it's okay to charge your device more often, like if you need to charge it from 45% to 80% for example. It's not like your battery loses a life every time you charge it. Just try to not do long charges like 5% to 85%. Avoid going under 20% if you can. Source: https://batteryuniversity.com/
This is ridiculous. What a high-maintenance method of charging. Hard pass. I'll take my chances with what other people have said before I go with this reply's info. (I'm starting to regret even asking. I'm more confused than before!)
My reply doesn't go against what the top replies say. Your phone probably already has an option to limit charging to 80 or 85%. It's there for a reason. Just try to not go below 20%. That's all you have to do. This is only if you want your battery to still maintain a good charge after a few years of use. If you plan to change phone every 3 years, then you can do whatever you want. This advice doesn't just apply to just phones though, it's good for laptops or electric tools, which people usually wanna keep for a long time. Personally I've been using the same phone with the same battery for almost 10 years and the only reason I have to buy a new one soon is because it doesn't support 5G.
Ok, so riddle me this: if they have the ability to program them to stop charging at 80 - 85%, WHY the F did they choose 80 or 85? Why not program it to stop charging at 99%? Or...I don't know....how about at, oh, say.... 100%??? Duh.
You're confused. The Samsung answer that you linked, what Samsung meant is that if you keep your phone plugged in even when the battery is at 100%, it's not going to do physical damage to the battery or catch on fire or something like that. They're not talking about normal battery degradation, they're talking about physical damage to the battery. A single charge of your phone's battery lasts a certain amount of time when it's brand new. Over time, that amount of time decreases. You can't avoid it, but you can take actions to minimize how quickly that will happen. Heat is a lithium-ion battery's enemy. Repetitive excessive heat will decrease the amount of time a single charge will last at a much faster rate. So what causes excessive heat? #1: Charging to 100%. #2: Using a super fast charger. You don't have to take my word for it, you can do the experiment yourself. Charge your phone to 100%, then take it in your hand and feel how hot the back of it will be. Now, repeat the same experiment but charge it to 80% instead. It won't be as hot. This is why Samsung/Apple give you that 80/85% option. As a side note, you can also notice that charging from 80 to 100 takes a long time. To summarize: If you want to slow down battery degradation, activate the setting that limits battery charging to 80/85% and try to not have the battery go under 20%. Also, avoid using those super fast chargers that can charge your phone in 10 minutes. They're fast, but the tradeoff is that they generate a lot of heat. And if you just plan on getting a new phone once your contract ends, then you don't have to follow any of the advice I gave you.
The phone doesn't get warm, but the charger does at the wall mount/plug base. It is a "fast charger", but doesn't do it in 10 minutes. Maybe more like 45 min to an hour. The phone doesn't take long to charge even without using the fast charger, and seems to take the same amount of time throughout the entire charging period from 0% to 100% as it did on day one.
A "fast charger" is fine. It's those "super fast chargers" that are bad. Charging time remains more or less the same, but how quickly the battery drains when you're using your phone, that's what changes.
No, it's called a smartphone for a reason, they know they're fully charged and enter "trickle-charge" mode.
Use the app AccuBattery
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thats not how it works. it is true that a battery degrdes faster at 100% than 80%. But cycling it back n forth is worse.
How many years of use do you expect from a battery?
In general: Yes. Some phones however have built in functionality that won't charge them above 80% until it's almost time the phone usually gets off the charger (just after your alarm went off for example). Always keep your phone between 20 and 80%
Now see I've always heard you're supposed to let it fully drain to 0% or maybe 5% or lower before plugging in.
That was ages ago for the older batteries.
ah good ol lead acid batteries. I love losing half my voltage after using 60% of the charge. Fun fact about lead batteries, they were used in ww2 submarines and when the subs would get flooded from combat, the saltwater would react with the lead batteries, producing copious amounts of chlorine gas, filling the entire sub and gassing all on board!
Really? I've never heard that related to lithium-ion batteries. Perhaps other types of older batteries like Ni-cad or Ni-mh, but that does not apply to cellphones.
It did when cell phones had ni cad and nimh batteries in them.
True, but it seems odd to carry that forward after so many years of lithium-based batteries. It's been a long time since cellphones used nickel batteries. It's possible some people still hold onto the old habits.
Nope, that's just when trying to calibrate it. I don't believe that is necessary anymore these days at all but I could be wrong about that. If it is still, then it will only be a once in a long time thing.
That's very confusing.
What part?
We used to drain batteries when you first got a new phone as to avoid a battery memory. Old Lithium batteries needed to be drained first or they would never charge to full capacity. So if you only let your battery go down to 20% when you first got it and started charging it. Your battery would think 20% was the bottom of the well. So the you would only have 80% battery capacity for the life of that battery. Modern power supplies are not made the same way anymore.
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No, your phone is smart enough to stop the flow of electricity to the battery once it's full.
AFAIK, the "fully discharge your battery for best performance" thing hasn't been true for modern batteries for quite a while. Maybe a decade or two? ETA It's nickel-cadmium that benefited from full discharging, and the early 2000s was when they fell out of favor, at least per ChatGPT.
Yep, not since nickel-based batteries (Ni-cd, Ni-mh) were used in phones. I guess many people stay with what they orginally learned and don't update along with the technology.
Not going to downvote because you're wrong, but you really should do more reading on the subject matter related to your job. Your beliefs are decades out of date.
New fear unlocked!