Hmm. The taking four bars just to stop time for five seconds seems like a little much. Maybe instead of that, have it like the time slow upgrade, where it takes a certain amount of energy per second. Maybe drain 1 bar each second it's active?
Or it could be a follow up upgrade from that, your idea first, then my idea , because time stopping is a lot more powerful
taht means it would only také 4 seconds...
I like Teodorp99's post, maybe it would have stages, mine, lvl1 takes 1 bar each second, one bar two seconds for lvl2, then Teodorp's idea.