18650 4s1p battery pack - NTC - BMS

This is a 4s1p battery pack module.

I wanted to build my own pack to avoid doing some soldering, so I designed it. Don't push the amps, the contacts aren't rated for high current.

⚠️ At this point, I assume you know the risk of dealing with lithium cells and balancing charges. ⚠️

You will need:

- 4x 18650 cells - One square BMS like this one - 8 spring contacts of 12*12mm (roughly, those are for 18650 cells) - (optional) one MF52B B3435 10k ntc probe - (optional) one 4s equalizer like this one only necessary if you're not familiar with your cells and/or if they are different brands/series. If you are using cells from the same manufacturer and with the same voltage, the balance should not be necessary. - (optional) if you're curious, I used a super cool fast-charge compatible 4s charge module, that is quite cheap here ! Steps:

- Print this model - Glue both halves back to back - Insert 4 bottom contacts (you might need to cut a bit of the small contact lip) - Solder the bottom contacts together like this

- Glue the BMS on top - Start doing the wiring and insert the missing contacts pads along the way (I find it easier to do this, instead of trying to solder them while they're on the print) - Finish the wiring - Solder the NTC probe - Insert the cells and tape the probe next to one cell - Do a first charge to activate the bms - Test the BMS ⚠️⚠️ and the ntc feature (an hairdryer works perfectly, it should cut the output) - Wrap some isolation paper - Done!  Here are some final results (before the isolation paper)