I tested charging a 5200 mAh (20 Wh) battery at 10W.
Its charging level at the beginning was 20%. The terminal voltage was 3.68V. Now, I applied 10W of charging rate to the battery. The terminal voltage has then risen to 3.94V, so risen by 0.26V.
Let's increase the charging rate until the terminal voltage increases by 0.26V again. Now, we have 4.2V of terminal voltage.
Is the charging rate now 20W 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?