fabieville
100 W
- Joined
- Jul 15, 2012
- Messages
- 114
I have a 24v 7s 30ah 18650 battery pack that I have been using for several months without a BMS installed.
Until recently I discovered that some of the strings where getting to be out of balance during discharging and charging. I would once a while balance the cells manually by connecting the strings in parallel and leave them for several hours until all strings where equal and then I connect them back to their original state to get back my 24v reading and then start using them. Without the BMS installed I use to charge up the entire pack to about 29.6v which after disconnecting the charger the rest voltage takes a while to drop to about 29.4v to about 29.3v or somewhere in that range.
Recently I installed a brand new 24v 7s 45A BMS. Before installing it i was thinking about balancing all the cells first as some of the strings where slightly out of balance. I was thinking of connecting them in parallel and leaving them connected in that way for several hours to get to a balance state in which all the strings would be reading the same exact voltage but I didn't do it before I installed the BMS, i just assume that the BMS would automatically put all 7 strings in a balance state during charging/discharging.
The issue that I am having now is incomplete charging with the BMS installed. During charging the voltage will reach up to just like before 29.5v to 29.65 or even a bit higher and no matter how long it stays on the charger as soon as u remove the charger the battery rest voltage drops to between 28.3v to about 28.8v. It does not remain in the 29.3v or 29.4v range like before when charging without the BMS. It just stays in the 28v range. The charger that I am using is a fixed 30v 17Ah regulated power supply.
Is this issue cause from not balancing the cells manually first before installing the BMS? How can I resolve this charging issue as my battery pack is not getting a full charge no matter how long it stays on the charger.
Please help me in this regards. I anxiously await your comments and suggestions.
Until recently I discovered that some of the strings where getting to be out of balance during discharging and charging. I would once a while balance the cells manually by connecting the strings in parallel and leave them for several hours until all strings where equal and then I connect them back to their original state to get back my 24v reading and then start using them. Without the BMS installed I use to charge up the entire pack to about 29.6v which after disconnecting the charger the rest voltage takes a while to drop to about 29.4v to about 29.3v or somewhere in that range.
Recently I installed a brand new 24v 7s 45A BMS. Before installing it i was thinking about balancing all the cells first as some of the strings where slightly out of balance. I was thinking of connecting them in parallel and leaving them connected in that way for several hours to get to a balance state in which all the strings would be reading the same exact voltage but I didn't do it before I installed the BMS, i just assume that the BMS would automatically put all 7 strings in a balance state during charging/discharging.
The issue that I am having now is incomplete charging with the BMS installed. During charging the voltage will reach up to just like before 29.5v to 29.65 or even a bit higher and no matter how long it stays on the charger as soon as u remove the charger the battery rest voltage drops to between 28.3v to about 28.8v. It does not remain in the 29.3v or 29.4v range like before when charging without the BMS. It just stays in the 28v range. The charger that I am using is a fixed 30v 17Ah regulated power supply.
Is this issue cause from not balancing the cells manually first before installing the BMS? How can I resolve this charging issue as my battery pack is not getting a full charge no matter how long it stays on the charger.
Please help me in this regards. I anxiously await your comments and suggestions.
