The most frequent cause of damaged LiPo batteries is incorrect balance charging. This can occur often in Marine Robotics as a stray drop of saltwater may land on a balance connector during a field battery swap! These protector boxes go around balance leads to protect them from “light” water spray - they obviously won't help much if the battery is submerged….

Remember that your cells should all be measuring approximately the same voltage when you start a battery charging, and if one is significantly different, and doesn't come within 0.1V during balance charging, the pack or balance connector may be damaged and need replacement. 

Modify the CAD however you'd like!

Safe charging!