Simple Trick For Replacing Game Boy Cart Batteries While Retaining Game Saves

[Adr990] wants to make sure his Game Boy game saves aren’t lost to aging batteries. They’re stored in SRAM with a small coin cell inside the cartridge to keep the memory energized when the game is not being played. But if you pull out the battery in order to replace it the data will be lost in the process. It turns out that you can hot-swap the battery without too much effort. As shown in the video after the break, he disassembled the case of the cartridge, then replaced the battery while the Game Boy is switched on. The edge connector feeds power which will keep the SRAM active while the backup battery is removed. We’re sure this could be done with a bench supply as well, but you’ll need to do your own testing before risking those prized game saves.

The other option is to backup your SRAM before replacing the batteries. We’ve seen an AVR-based cartridge dumper, and also one that uses an Arduino. Both should be able to read and write SRAM data.

22 thoughts on “Simple Trick For Replacing Game Boy Cart Batteries While Retaining Game Saves

  1. Great! Now the word is posted on Hack A Day lots of people will read about this and will be able to save their save files. :)

    Also, this method also works for the NES, SNES, N64, GBC and GBA. So most commonly also on other game systems which use the battery save method. :)

    Thanks for posting this.

  2. You could always hook up a variable DC power supply to the battery lines in parallel to maintain power while replacing it. Would allow for proper battery installation rather than electrical tape.

  3. is there a backup battery like this inside the gameboy itself that might be maintaining a bios or other ROM? My gameboy won’t boot anymore and there’s no visible signs of damage on the case, in the battery compartment, etc… I need to get around to taking it apart.

    1. I can tell you nothing from the original GB to the GBA & variants have any internal battery. It’s pretty unusual for them to break, they’re built pretty tough, especially the GBC & original GBA.

      1. Bummer. I was hoping this would lead to an obvious solution. Oh well, was worth a shot. If I can get my GB (original) to power up, I might be able to save my game records with this method, so now I’ve got more motivation to do both! Thanks, Hackaday!

      2. I agree with the GBC argument, however I don’t know if the orignal GBA was really that tough. The screen on mine went out in just over a year. My GBA SP still kicks for some reason though… I would have figured the flimsy device would have died sooner.

      3. Original gray brick was built like a tank too… except for the connection between the LCD and the main board.They lose columns of pixels as they age. Both of mine lost edge columns, so it’s not much of an issue, but I’ve heard of them striping straight down the center of the display.

  4. I love it when I see smart approaches to problems like this. I replaced a (dead) cart battery a while back and wondered if there was a way to change an old battery before it was too late and keep the save data. I was thinking along the lines of a capacitor or something. And now this – genius.

  5. i did this same thing to an ancient 5000$ car repair machine :)

    it used a ni-cd rechargeble and it was about to die completely.
    (end of life, wouldnt take a charge)
    luckly for us the manufacturer included a warning code on the display and the owner kept it on until i got there.
    (he had service manual with error codes)

    apparently, if i had screwed up, it would have costed around 1000$ for a guy to come over and reprogram(install) the PROG.-R.A.M. lol doesnt even sound right! program-ram ??? yeh.

    the way i solved it was by paralleling the old battery with standard AA batteries and then desoldering the orig, then solder in an exact replacement and cut off the AA’s. worked like a charm!

    had to physcaly remove the PROGRAM-RAM board from the unit first, so i had to use the AA’s and couldnt just do it with power on

    PS: actually i think the company that had made it had disapperared long ago, as it was a huge unit with pnumatic and other stuff inside it
    (for testing car stuff) including built in CRT monitor and flourecent lamp in the top.
    alas it might have been the last of it’s kind, and probably is long since dead by now. :(
    (its been more then 5 more years since then)

  6. I just want to say that NOT all GBA cartridges use SRAM as some of the newer games use FRAM. Why is this important? It means that the save data isn’t associated with the battery so the removal of the battery would ‘t affect the save data. I know this from removing the battery on both Ruby and Sapphire games without losing save data. I believe very few models have FRAM which is both good and bad. Good because if the battery dies, your save data is fine and should theoretically last for many years, bad because it only has 10,000,000,000 read/write per bit. The less times you save, the better.

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