I enjoyed the game very much!
I found a bug in which the battery gets duplicated, I haven't tried to recreate the bug, but my guess is that it has something to do with the sequence after failing to charge the battery.
After failing to charge the battery, I got my dead battery back, then left the charging station to do some other quests, after I found the solution to the battery puzzle, I went back to the charging station with a dead battery inside the machine (one dead battery in inventory, another one inside the machine).
* the charged battery is the duplicated battery that's inside the machine.