Hey folks,
I’ve been following this guide on assembling a DIY 18650 battery pack and I’ve run into something I can’t quite figure out.
I built a small pack using spot-welded nickel strips and tested each cell before assembly. All the cells were balanced around 4.1V when I started, but after wiring everything up, one parallel group is showing about 0.2V lower than the others. I double-checked my welds and connections, and they seem solid.
Is this normal cell drift after assembly, or does it point to a weak connection or bad cell in that group? I’m hesitant to throw a BMS on it before I understand what’s causing the mismatch.
Anyone run into this before? Should I break it down and re-check the cells, or is there another common issue I might be overlooking? Everything About the 18650 Battery: Uses, Specs, and Buying Guide - Kasuo was helpful but, practically, i still can’t pinpoint the issue.
Thanks in advance!
