Personally hasn't happened to me, but I've heard it happening to others. Actually I recently saw it happen to a Youtube streamer, almost the exact same thing. Using a generator to charge a battery bank, which powered multiple traps. Just logged in and all engines and all but one battery were gone.
It looks like it's been reported in the General Support forum. I haven't read through it, but it sounds like this particular issue was on a server. Not sure if you're playing on a server or not, but it might be similar to your issue:
I know for sure the Youtube player I mentioned was playing single player, so I don't think they were playing off a server.
