Crysis 3 - Quick question on how to supercharge your nanosuit?

[SkScotchegg]

Hi there, please can anyone tell me what button you press on a battery to supercharge your suit? I think I've almost completed the game and I've not played for a while but want to finish the game today, the final part where I am now there's batteries which recharge my nanosuit and alien weapons but I cant figure out how to supercharge your suit? How do you use the battery?

edit: Oh it's ok now, it must have been a glitch before, I'm on final boss now and its working, it says Press F to supercharge. It didnt say that before but not its working for some reason.

Thanks in advance.