I've converted an existing 18v DC battery pack (for a power tool) to use replaceable 18650 cells. My plan is to charge the cells in a "smart charger" and discard the OEM charger. I'm only getting about 1/2 of use from the tool before power cuts out. This is an original battery pack which failed in service and I suspect the board may be toast.
If I wire up the 5 cells (in series) directly to the load pins that connect to the tool, do I need to consider some sort of discharge or thermal protection inline as well? Specifically, I'm looking at This one which is good for 40V. Thoughts?
(update: Considering the
5S 21v 18v BMS board here since it's a little smaller https://www.ebay.com/itm/272724717408)