I tested charging a 5200 mAh (20 Wh) battery at 10W.
Its State of Charge level at the beginning was 20%. The terminal voltage was 3.68 V. Now, I applied 10 W of charging power to the battery. After some time, the terminal voltage rises to 3.94 V, which means that it rose by 0.26 V.
Let's increase the charging power until the terminal voltage increases by 0.26 V again, to 4.2 V of terminal voltage.
Is the charging power now 20 Wh or higher?
- 00 Watts at 3.68 Volts
- 10 Watts at 3.94 Volts
- ?? Watts at 4.20 Volts ?
Is there a formula for that?