Super alternative to a new controller

The controller of my PS3 (first generation) has complained repeatedly about a dead battery. So I thought, replace new controller or battery?
Because the controller is ansich still perfectly fine and the price of the battery is a bargain compared to a new controller, I have decided for the exchange. I think the exchange can be performed by any of not just three left hands has problems. The controller can be determined by solving the four screws quite easy unfolding and already quasi the battery falls into the hands of a then. The battery itself is plugged in with a connector on the motherboard of the controller. So plug out, new battery then reinsert it and screw together controller again, ready.