Common eBike problems and solutions

Hey everyone!

I'm diving into the world of custom eBike builds, and it's been a blast so far converting my old hardtail mountain bike into a commuter beast with a mid-drive kit. I'm curious to hear from others who've gone the DIY route: what are some of the most common issues you've encountered with your custom builds, and more importantly, how did you troubleshoot or solve them? I'm thinking anything from motor cutout issues on long climbs to battery management system (BMS) quirks or even just weird wiring gremlins. Share your wisdom!