One of my controllers battery died. I guess that's what I get for leaving it out without charging all the time when I fall asleep on the couch watching Netflix.
The OEM battery is a 3.7V like 540mAH battery. Being the type that likes to modify stuff I decided to try upgrading it to a larger capacity battery. What I came up with was this.
A battery from Blackberry. The CS-2. Its only about 1/16th thicker and has double the mAH. I haven't tried it yet since it's still in the mail but it should work. Anyone upgrade their battery in their controllers?