BAK 14.4v 4.4ah 63.36wh Li-Ion Module with BMS
Around $80/kWh for packs with a BMS!
Here are awesome BAK 4s2p 14.4v 4.4ah 63.36wh packs with a working BMS. The positive (red) and negative (black) wires allow charge and discharge current so you can use these packs as is. I would recommend keeping the charge and discharge limited to 4 amps per pack. The other 3 wires are not needed. Just cut the positive and negative wires off the connector and those will be your main wires.
Cells used are BAK brand which are excellent cells trusted by the medical industry. These are used medical packs but medical packs tend to test excellent because they don't really get cycled too many times, often times just used as backup power. The packs can charge up to 16.8v.
There are 3 options of usage for these packs.
Use the packs as is - Charge up each pack to 16.8v, connect as many as you want in parallel to make a nice 14v pack. Most inverters will take up to 15.5v so at this price, even if you can only charge up to 15.5v to work with a 12v inverter, you can build a 12v pack for a fraction of the cost of anything else out there with a BMS, especially since charging this pack to 15.5v you should get around 80% capacity compared to charging up to 16.8v but many studies show you will more than triple the cycle life by undercharging that amount.
Use the cell configurations as is - Simply remove the shrink wrap and the BMS. You will have cells in 4s2p configuration. You can easily configure these into higher voltage packs. For example you can series 3 of these packs into a 12s module. Then cut one module in half to make a 2s3p module. That way you can make a 14s2p module using 3 1/2 packs.
Salvage the cells - You can also salvage the 8 cells out of these. Remove the shrink wrap, the BMS, wires, and nickel. I would recommend saving the BMS, wires, and nickel for scrap because you can recover some scrap value out of those boards or even sell the 4s lithium ion BMS
Each module weighs 1 lb.
Packs are 3" wide, 1.5" deep, 3" tall. Wire leads are roughly 4.5"
Pack full charge voltage is 16.8v
Pack full discharge voltage is 11.2v