A UPS battery fails, oh well we have a spare and these things support hot swapping. Heck, I can even do this live in the day… isn’t technology great.
Oops, seems the cable was snagged on some internals and upon removing the battery decided to clean cut through it! Luckily the power was still flowing to the attached servers and I could cleanly power them down.
So what did this teach me? I hate electricity and things sparking at me… and maybe next time I’ll cold swap.