72V batteries -> lyen MK I -> BMC V3T = stutter w/load

[999zip999]

The purpose of the bms is to make sure no cells go above 4.2v. ( hvc) Is best if the the cells hit 4.1v-4.15v and not over 4.2v.. Also I would not let them go lower than 3.3v maybe 3.5v and this will help in your battery not getting out of balance. This means you are the bms in charge of not killing cells. I charged a pack of 15s at 61.5v and one cell was dead so the other cells took the charge at 4.35v and one cell at zero. The 61.5v had to go somewhere and not into the dead cell 0v. so it filled the other 14s cells to high I will test this battery for damage.

 

[The Stig]

The purpose of the bms is to make sure no cells go above 4.2v. ( hvc) Is best if the the cells hit 4.1v-4.15v and not over 4.2v.. Also I would not let them go lower than 3.3v maybe 3.5v and this will help in your battery not getting out of balance. This means you are the bms in charge of not killing cells. I charged a pack of 15s at 61.5v and one cell was dead so the other cells took the charge at 4.35v and one cell at zero. The 61.5v had to go somewhere and not into the dead cell 0v. so it filled the other 14s cells to high I will test this battery for damage.

true so i'm gonna go ahead and put a bunch of diodes in the charge circuit to bring it down to 4.15. and raise the controller lvc.

i'll recheck my string voltages

 

[The Stig]

I have a question for you guys/gals. My charger cuts off at 42V but my pack should be charged no more than 41.5V, is there any way to lower the voltage of the charger by 0.3-0.5 V? I've tried using a diode(0.7V voltage drop) to take it down to 41.3V but the charger won't turn on again unless it drops below 41.1 V. This may be a problem because this battery is in series with another battery that stays at 41.5V off the charger so thats almost 0.5V a difference. I would like to keep the two batteries balanced.

The BMS is damaged but the balancing still works so at least that gives me hope.

 

[amberwolf]

If the charger has adjustment pots in it, then you just have to find out which one does the voltage adjsutment. If it's one of the ones already figured out here on ES or elsewhere, just do what the results say to, and you're set. If not, you'd have to do the testing on your own.

If there are no pots, then the control voltage point has to be found, and then a pot added in place of or in parallel with the resistor to that point, so you can then adjust it to your needs.