Basically you need to just go for them first. The faster you take the out the better off you are. They slowly drain the power and if it gets below like 50% you start getting attacked by ghosts and things like that and it gets really messy. So yeah, just go straight for the first battery mimic thats draining the power, then after its dead use R2 to FLee and get to the next one as fast as posssible. Killing them also restores the power and as long as you kill them fast you'll be fine.