Lithium batteries are charged using CC-CV scheme. That means, you need power supply
- with voltage 5x4.2 = 21V
- with current limit based on type of used batteries, for 18650 it's usually about 1A
To improve charging speed, you need higher current, not higher voltage.
What cells are you planning to use?
Yes. I know that.
That is why I am asking the question.
I am using (in this specific case) cells from fuji453562(21CP9/36/64 in a 2P 5S configuration to give me 2 AH @ 21 volts.
At 21 volts (supplied) it takes whatever current it pleases, from flat maybe 200 ma or so dropping to zero when charged. It does not clip the voltage obviously. Running it from a 2 amp or a 200 amp supply will make no difference.
What I need to know is if the BMS will regulate correctly for voltage up to the requirements of the battery from any source provided that source is greater than the charged battery voltage and less than the chip maximum.
Sorry if I did not explain the question correctly, I thought it was clear enough.