- charging those as a pack isn't dangerous, however, since each cell monitors on itself, it's different than the protection PCBs designed for a 2 cell pack, which is monitoring both cell voltages separately (wiring the battery center wire isn't optional). This way it's not the overall voltage of the pack that is monitored, but each cell individually (VERY important on li-ion).
What can happen is that one cell goes off (prot pcb reached the low thresh) before the other, and the whole pack is cut since they are in //
- same will happen for charging
- hence if you start making a pack with a low charge cell, the pack will not last long. Conclusion, make sure you fully charge your cells prior making the pack. No cell are perfectly identical, so in any case, the pack might start becoming asymmetric and the only way is to take the pack apart and recharge individual cell.
You probably don't have to bother with this if you are using brand new batteries you get from DX or elsewhere, however, pay attention anyway. I started making one yesterday with batteries that were in my negotiator (making a recharge port version on that one, it's upgrade time) and the batteries were asymmetric.
Erv'
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