To start this off I got these two old PlayStation 4 controllers. Both are model CUH-ZCT1U. They actually work great but the batteries would last maybe 20 to 30 seconds at most. I recently purchased a battery 2 pack. It was not a bad price so it was worth trying to do the replacement. They came with a small screwdriver and a plastic spudger. I watched a few YouTube videos about how to do this. It did not look too difficult. I started working on one. It went by smoothly after getting it opened. It was the second one that caused me a LOT of trouble.
There are two little springs with arms that keep the left and right triggers pushed out so they would be responsive. After replacing the battery I accidentally popped out one of the triggers and the spring came out. I eventually figured out how to put it back after watching another YouTube video. Sadly while I was fixing the right trigger I accidentally made the left one pop out. At that moment if I was a drinking man I would have stopped and partaken in the booze. After about 2 hours of fat-fingering the triggers I was able to get them both properly put back on so I could close it up. So, would I do it again? I am not so sure. I am glad I got it done though. Just a word of advice. If you are not VERY careful you will have to fiddle around with them. Not fun.