Sharkey
1 µW
- Joined
- Jul 31, 2018
- Messages
- 2
I'm contemplating using a multi-cell, in this case a 6 cell, charger to balance a 10s10p 18650 pack. The idea would be to use the balance leads to bring all parallel connected cells up to the 4.2 volt cut off point for the charger. I realize that probably the only way this would work is to connect every other 10p grouping to the charger using the balance wires. And then when those cells have been brought up to the 4.2 volts (where the charger shuts off), reconnect the remaining cells that were not charged in the first set of cells. My idea is based on the fact that each of the 10 series connected parallel groups has a balance wire connected to the positive terminal and another one to the negative terminal. So... starting with cell 1, balance wire 1 is connected to the positive terminal and balance wire 2 is connect to the positive terminal of cell 2. And... this is also the negative terminal of cell 1 since they are connected together in series. And that's why I'm assuming I couldn't charge adjacent cells at the same time. In other words, for cells 2 through 9 share the remaining balance wires. And of course, the 10th cell would use a balance wire connected to its negative terminal which, of course, is the negative terminal of the entire pack. As a result, in theory, all 10s groups would be at 4.2 volts. I.E. top balanced. Which, to me, seems better than using a BMS which, as I understand it, brings the pack up to where at least one of the parallel cells is at 4.2 volts and then bleeds off voltage to the same voltage level of the lowest cell group in the pack. This seems a bit inefficient and backward to me and you end up with a pack at the voltage of the lowest cell.
I'm looking for reasons why this would either not work or not be a good idea. I do realize that is less automatic than using a BMS, but I don't need the BMS function to stop discharge of the pack below a safe point. This is an auxiliary pack in parallel with the primary pack which is protected with a BMS and thus will be shut down before reach a damaging low voltage.
I'm looking for reasons why this would either not work or not be a good idea. I do realize that is less automatic than using a BMS, but I don't need the BMS function to stop discharge of the pack below a safe point. This is an auxiliary pack in parallel with the primary pack which is protected with a BMS and thus will be shut down before reach a damaging low voltage.