15.2v 8ah 121.6wh Battery Module with BMS 4 cells
These modules have 4x 8ah cells inside in 4s1p configuration. We tested a lot of these packs and they were between 80-90% capacity at 0.2c discharge rate. The packs we tested some of the cells went a little out of balance towards the bottom of the discharge cycle so they are top balanced and these packs will cycle through the BMS. They just might cut out a little early if they are out of balance towards the end of the discharge. I would recommend to salvage the cells out of these packs but you can test the modules and likely use them as is. If the discharge test cuts out a little early then the cells likely are out of balance and those packs I would salvage the cells or limit the discharge cut off to maybe 3.2v per cell. You can carefully use a solder sucker tool and make sure you don't short the cells when doing that. Keep the packs at an angle so the solder doesn't melt towards the next cell. Or simply leave the top PCB board in place but disconnect the BMS on the front. The PCB is what makes the series connection so keep that in mind. We are selling these for just $2.00 per cell for 8ah cells that are mostly testing between 80-90% capacity. The BMS is a bonus. And if the pack works as is that is an even greater bonus. All cells are guaranteed to have voltage as we tested every pack. The 2nd photo shows the BMS, the 3rd photo gives a more close up image of the PCB which makes the series connections. The tabs are just soldered in place.
These are nice, compact, and clean modules that were originally likely used in backup lighting systems.
We tested the BMS at 5a charge and discharge.
Module fully charged - 16.8 (4.2v per cell)
Module fully discharged - 11.2v (2.8v per cell)
Pack dimensions - 4.25" x 4.25" x 2.25"