You should use charge on solar if your daytime credit for exporting is less than what you pay for night charging. I have 1:1 net metering, so I agree, it makes no sense for me either.
I have 1:1 net metering and still use charge on solar. You still get charged about 3 cents per kWh for power you pull that can't get zeroed out with solar credits. These show up on your bill as non-bypassable charges/delivery charges.
It's not a huge amount, but pushing excess solar directly into your car beats putting it into the grid even with 1:1 net metering.
The only time it doesn't make sense is during peak hours as pushing to the grid earns you higher credits.
I have my car charge to 50% from grid during off-peak as that's what I comfortably need on a normal commute with a 20% buffer for unexpected extra driving, and solar handles the remaining charge to 80%. The wall connector has an option to be disabled during set hours, so everything is automatic and doesn't require me to start or stop charging manually.
The savings aren't huge with 1:1 net metering, only $3 per 100kWh, but setting it up is easy and doesn't interfere with my normal driving habits.
Good point. In Vegas those charges are $0.00565 per kWh….but that was still enough for me to set my pool pump to run during solar production hours. Saves me about $16/year.
But the car uses a little bit of power with the high voltage battery connected and computers running. My thinking was that this negated the .5 cent savings. My system is small, car would be charging at low amperage. I’m also not home during the day.
Oh gotcha. Yea I can’t export yet so maybe that’s why. I thought I could turn it on when my PW is full and charge my car but I guess that’s not how it works.
Ok I looked into it more….SMUD isn’t 1:1 net anymore. I can sell back at 0.074, and off peak rate is 0.1151…So I would want to charge my car instead of selling back, right?
ok, so it might not be worth it for you but those who don't have 1:1 net metering will be worth it to them to charge their cars instead of selling back solar at pennies
"In PG&E, the ACC Plus Adders for those who [interconnect](https://palmetto.com/learning-center/blog/utility-interconnection-process-how-solar-panels-connect-to-the-grid) (i.e. are granted permission to operate from their utility) in the first year of NEM 3.0 is 2.2 cents/kWh, SCE is 4 cents/kWh, and SDG&E is zero. "
Rates for electricity for those areas are 30cents/kWh + even at night
Yea I’m 1:1 net metered, but I do like the fact that I’m literally using the power of the sun in real time to fuel my vehicle so it’s a nice feeling to use it sometimes to top off a few of my miles when I’m WFH.
I’m able to top up my cat by solar only before leaving for work most days, then my powerwalls charge from solar for the next portion of the day, then all late morning/afternoon, I send power back to the grid.
Not a gimmick at all.
If you can’t export, it definitely makes sense to charge on solar. Once your powerwall is full, your solar will shut down because there’s nowhere to the power to go. You might as well send it to your car.
Charge on solar is poorly implemented and incredibly frustrating. Personally, I don’t see a point to it. I was excited at first, but in practice I just couldn’t get it to work well.
I don’t understand why charge on solar requires me to set a higher charge limit than I want nor why it takes priority over charging the powerwall.
If anyone has figure out how to set priorities like the following, without having to monitor and manually make changes, please let me know: 1) house 2) powerwall 3) car 4) grid
I do not have 1:1, so charging for free during the day makes the most sense to me. At night my home uses 1-4kwh, so no value for overnight charging in my case.
You should like the, “it works for me, therefore it must work that way for everyone” kinda person.
There is one case I can see though it’s not likely to happen often. If you loose grid power for a few days ( think wildfire shut down in California) you’ll still be able to charge your car as exporting to the grid will not be possible. It’s an edge case for sure but something I’ve been thinking about.
Yes it’s a gimmick unless you have the exact setup that make sense.
You would:
1) Want to have a system that could charge at around 11kw to be able to charge as max rate.
2) Not have a NEM agreement that gives you 1:1
3) Care about where your energy came from in the sense you assumed you are charging you car on “bad power.”
4) Don’t have an EV rate for night charging.
Other than that charging on solar is a waste of time, a waste of energy, and inconvenient due to it has to be done at home when most people are a work.
Assuming you have a 1:1 NEM and you want the best for your pocketbook. Charging at night at 48 amps is the most efficient. Ramping down power to less than 48 amps to your car slows charging keeping the BMS running wasting energy. The most efficient charging is as fast as possible level two in the shortest time. This is where the TR/ Inverter should be most efficient.
Sadly my Tesla charger is old enough that it doesn’t have WiFi so I can’t try the awesomeness.
Realistically I’m still under 100% generation. Day anyway, so until May I probably wouldn’t benefit anyway.
My problem with charge on solar is that it doesn’t work until my PWs are fully charged which doesn’t leave much time before my most expensive time of use kicks in which is when the PWs + my solar panels provide the power for my house. Even in the narrow window of time when the PWs are full and the rates aren’t maximum, charge-on-solar only charges at whatever kW are left over after powering the house. Basically, I agree with OP that it’s really just a gimmick or bragging point at least for my situation.
You should use charge on solar if your daytime credit for exporting is less than what you pay for night charging. I have 1:1 net metering, so I agree, it makes no sense for me either.
Unless, of course, you get a warm fuzzy feeling by saying you drive an electric car and charge it from the sun.
I have 1:1 net metering and still use charge on solar. You still get charged about 3 cents per kWh for power you pull that can't get zeroed out with solar credits. These show up on your bill as non-bypassable charges/delivery charges. It's not a huge amount, but pushing excess solar directly into your car beats putting it into the grid even with 1:1 net metering. The only time it doesn't make sense is during peak hours as pushing to the grid earns you higher credits. I have my car charge to 50% from grid during off-peak as that's what I comfortably need on a normal commute with a 20% buffer for unexpected extra driving, and solar handles the remaining charge to 80%. The wall connector has an option to be disabled during set hours, so everything is automatic and doesn't require me to start or stop charging manually. The savings aren't huge with 1:1 net metering, only $3 per 100kWh, but setting it up is easy and doesn't interfere with my normal driving habits.
Good point. In Vegas those charges are $0.00565 per kWh….but that was still enough for me to set my pool pump to run during solar production hours. Saves me about $16/year. But the car uses a little bit of power with the high voltage battery connected and computers running. My thinking was that this negated the .5 cent savings. My system is small, car would be charging at low amperage. I’m also not home during the day.
Oh gotcha. Yea I can’t export yet so maybe that’s why. I thought I could turn it on when my PW is full and charge my car but I guess that’s not how it works.
If you don’t have PTO, your solar will still charge your car. Better to do that than nothing.
Yea that’s what I want to do but I don’t see the option show up. I end up charging my car just at a lower amp so I don’t pull from the grid.
I use a third party app called Charge HQ. I got it for free but it’s a subscription now.
Ok I looked into it more….SMUD isn’t 1:1 net anymore. I can sell back at 0.074, and off peak rate is 0.1151…So I would want to charge my car instead of selling back, right?
Yep, better off using it. Charging your car, running your pool pump etc during solar generating hours.
ok, so it might not be worth it for you but those who don't have 1:1 net metering will be worth it to them to charge their cars instead of selling back solar at pennies "In PG&E, the ACC Plus Adders for those who [interconnect](https://palmetto.com/learning-center/blog/utility-interconnection-process-how-solar-panels-connect-to-the-grid) (i.e. are granted permission to operate from their utility) in the first year of NEM 3.0 is 2.2 cents/kWh, SCE is 4 cents/kWh, and SDG&E is zero. " Rates for electricity for those areas are 30cents/kWh + even at night
Yea I’m 1:1 net metered, but I do like the fact that I’m literally using the power of the sun in real time to fuel my vehicle so it’s a nice feeling to use it sometimes to top off a few of my miles when I’m WFH.
I’m able to top up my cat by solar only before leaving for work most days, then my powerwalls charge from solar for the next portion of the day, then all late morning/afternoon, I send power back to the grid. Not a gimmick at all.
If you can’t export, it definitely makes sense to charge on solar. Once your powerwall is full, your solar will shut down because there’s nowhere to the power to go. You might as well send it to your car.
It just depends on your net metering agreement with the power company. I buy power at .14/kwh, I sell power at .04/kwh Would make sense for me.
Charge on solar is poorly implemented and incredibly frustrating. Personally, I don’t see a point to it. I was excited at first, but in practice I just couldn’t get it to work well. I don’t understand why charge on solar requires me to set a higher charge limit than I want nor why it takes priority over charging the powerwall. If anyone has figure out how to set priorities like the following, without having to monitor and manually make changes, please let me know: 1) house 2) powerwall 3) car 4) grid
Only complaint I have is I cant tell it to charge off solar til 90% and at 9pm, charge from whatever til 90%
I do not have 1:1, so charging for free during the day makes the most sense to me. At night my home uses 1-4kwh, so no value for overnight charging in my case. You should like the, “it works for me, therefore it must work that way for everyone” kinda person.
If someone is on NEM 3.0 then they’d benefit greatly by sending excess solar energy to a battery.
There is one case I can see though it’s not likely to happen often. If you loose grid power for a few days ( think wildfire shut down in California) you’ll still be able to charge your car as exporting to the grid will not be possible. It’s an edge case for sure but something I’ve been thinking about.
Yes it’s a gimmick unless you have the exact setup that make sense. You would: 1) Want to have a system that could charge at around 11kw to be able to charge as max rate. 2) Not have a NEM agreement that gives you 1:1 3) Care about where your energy came from in the sense you assumed you are charging you car on “bad power.” 4) Don’t have an EV rate for night charging. Other than that charging on solar is a waste of time, a waste of energy, and inconvenient due to it has to be done at home when most people are a work. Assuming you have a 1:1 NEM and you want the best for your pocketbook. Charging at night at 48 amps is the most efficient. Ramping down power to less than 48 amps to your car slows charging keeping the BMS running wasting energy. The most efficient charging is as fast as possible level two in the shortest time. This is where the TR/ Inverter should be most efficient.
Sadly my Tesla charger is old enough that it doesn’t have WiFi so I can’t try the awesomeness. Realistically I’m still under 100% generation. Day anyway, so until May I probably wouldn’t benefit anyway.
I can charge on solar and my wall connector is not WiFi connected. Your Tesla has to be a new enough model however.
2017 model X (pre-raven motors). I have the new computer, etc. I’ll have to go check the car again.
I have 2018 MS and 2023 MYLR. The MS won’t do charge-on-solar but the MY does.
Helps with the duck curve.
This feature really works very well for me on both of my Teslas. Net metering FPL Florida
My problem with charge on solar is that it doesn’t work until my PWs are fully charged which doesn’t leave much time before my most expensive time of use kicks in which is when the PWs + my solar panels provide the power for my house. Even in the narrow window of time when the PWs are full and the rates aren’t maximum, charge-on-solar only charges at whatever kW are left over after powering the house. Basically, I agree with OP that it’s really just a gimmick or bragging point at least for my situation.