I have a 10S so full charge should be around 42V, 33.6V for 8S, what voltage do you usually get on your fully charged pack?
4.2 Volts per cell is pretty much full
Full charge voltages: 3S - 12.6 V 4S - 16.8 V 5S - 21.0 V 6S - 25.2 V 7S - 29.4 V 8S - 33.6 V 9S - 37.8 V 10S - 42.0 V 11S - 46.2 V 12S - 50.4 V
My charge stops at 95% every time, 95% means 41.3V
depends on your charger. I choose to charge my pack to only 41V instead of 42V - keeps them healthy for longer.
I use a regular brick charger, what voltage do you guys (with this charger) get when the led turns green?
Stopping at a 41.3 is very healthy for the battery.
I guess It stops at 41.3v because one pack has higher voltage than the rest, so BMS shots the charging down
Where did you get that?
It is a lab power supply - you can get them in almost every electronics shop.
The way it works, It starts in CC mode delivering 5a at a voltage just above the current battery voltage until the battery gets to around 41v then it switches to CV mode and delivers 42v with the current dropping slowly until the battery is full. The bms starts trimming cells to balance at 42v meanwhile the power supply continues to deliver a small amount of current to fill the low cells.
Yes, that is exactly the one I have.
Well ideally that’s what is happening inside the bricks but the results don’t show that.
My brick chargers fail to charge my packs fully because they shut off prematurely. The power supply gives results more like a hobby charger
I believe that charging a pack 100% does not harm or shorten it’s life. But that discharging a pack too low can be harmful and shorten its life. http://techguylabs.com/episodes/1022/how-can-i-make-my-batteries-last-longer In this link they are talking about device batteries but the basic principle is the same for all lithium batteries.
Table 4: Every 0.10V drop below 4.20V/cell doubles the cycle but holds less capacity.
I don’t have time at the moment to read the whole article but I will later. One quick point , charging a sinlgle cell to 4.1v would be easy enough. But if your charging a pack of many cells with a BMS that starts balancing at full charge, how is it going to balance the pack if you never charge the pack full?
How are you so sure that BMS does not balance while charging even though it didn’t reach 42V?
The most logical method to balance each pack would be to send more amps to the pack with less charge as soon as the charging starts and keep doing it until it reaches 42V