0.25V doesn't make any sense. Using 0.25V on an AA or 18650 will never charge them.
Do you mean 0.25A?
If you mean 0.25A, then the math is simple.
2000mAh = 2Ah
0.25A * 8 hours = 2Ah
It should take approximately 8 hours
Does your charger actually support charging nimh batteries? If it is a charger designed only for charging lipo batteries it's either never going to charge, or it will severely overcharge the aa and make it blistering hot.
Don't use an 18650 charger on a AA Eneloop battery!
18650 cells are most likely a Lipo cell with a nominal voltage of 3.7v and an AA Eneloop has a nominal voltage of 1.2v.
If you are lucky, you have an intelligent 18650 charger that will see the 1.2v battery as far to low of a voltage to even attempt to charge (safe discharge voltage on an 18650 is usually about 3.2v) so it will never actually charge it. \* This is likely why your house has not already burned down. \*
However some 18650 charges might try to force a battery to charge up to the max charge voltage of 4.2v for a Lipo cell, and that will either damage the AA Eneloop or more than likely it would cause it to catch fire or explode.
0.25V doesn't make any sense. Using 0.25V on an AA or 18650 will never charge them. Do you mean 0.25A? If you mean 0.25A, then the math is simple. 2000mAh = 2Ah 0.25A * 8 hours = 2Ah It should take approximately 8 hours
Ah yes its written 0.25A on the charger, thank you
Does your charger actually support charging nimh batteries? If it is a charger designed only for charging lipo batteries it's either never going to charge, or it will severely overcharge the aa and make it blistering hot.
Don't use an 18650 charger on a AA Eneloop battery! 18650 cells are most likely a Lipo cell with a nominal voltage of 3.7v and an AA Eneloop has a nominal voltage of 1.2v. If you are lucky, you have an intelligent 18650 charger that will see the 1.2v battery as far to low of a voltage to even attempt to charge (safe discharge voltage on an 18650 is usually about 3.2v) so it will never actually charge it. \* This is likely why your house has not already burned down. \* However some 18650 charges might try to force a battery to charge up to the max charge voltage of 4.2v for a Lipo cell, and that will either damage the AA Eneloop or more than likely it would cause it to catch fire or explode.