Replacing GBA cartridge battery
Recently, I wanted to test a Pokémon Ruby cartridge I’ve had lying around for a while. It had quite a lot of playtime on it, so I was keen to see if the save data was still intact. After powering on the GBA, I was greeted with an unfortunate, but somewhat expected, message.
The internal clock-battery had run dry, a common problem with these kind of cartridges. Luckily, an empty battery doesn’t prevent you from playing the game, but timed events will stop working. To fix this problem, you can quite easily replace the empty battery with a new one. The only difficulty is finding one of the right size, with attached solder tabs.
Suitable replacement batteries are the standard CR1616 3V lithium types. These batteries (with attached solder tabs) are readily available on eBay for only a few dollars. Desoldering the old battery is easy if you lift one tab at a time. To solder on the new battery I had to bend the tabs a little bit into shape with some pliers. I also added some tape to the back of the battery as an extra precaution against short circuits. Make sure to connect the battery with the right polarity and with enough clearance to the ROM chip underneath. After re-assembling the cartridge and tightening its single tri-wing screw, I was pleased to see the game working as expected with all save data still present.