Most Game Boy games (and by that I mean the pre-Advance time) are saved into the cardridge and powered by a battery so that this memory will not vanish.

In a future, far far away, the battery empties, which will lead to a loss of the save state as there is no power source to hold the save state in the memory.

A solution is to replace this little battery and have a saveable game again. So I'm now playing Dragon Warrior Monsters and achieved pretty much everything in the game. I know I will play that game again (as I replay it often since release).

My fear is that I will lay back the cardridge until digging it out again. By that time the battery may already be empty (never replaced it since I bought the game).

What are my options if I want to replace the battery precautionary and keep my save game?

(This may include tinkering tips, extra hardware or a simple "won't erase your save game anyway".)

I ask this question specifically for the "pre-Advance" GameBoy cardridges:

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5 Answers 5


Open the cartridge and plug it in a GBA. Turn it on and exchange the battery while the system is on. Just make sure to not touch any contacts that could damage the cart, focus on the battery and make sure it doesn't lose power while you're working on it.

This works because when the batteries start to wear out, they can still work through the GB's own battery, but once that one also runs out, you'll be out of power for both the cart and the system.

  • Hi! Please read "esoterik"`s answer, as he states that batteries are soldered on the plate. Therefore your answer wouldn't be easily possible. Do you agree?
    – Trollwut
    Feb 26, 2015 at 13:47

There are ways you can copy the backup data from the cartridge to your computer.

It'll cost some money in buying the hardware to do that, but IMO it is way safer than replacing a battery while the device is on.

  • You could probably also find a service that does this for a lower cost than buying all that hardware for yourself. Feb 22, 2015 at 21:57
  • How would this service work? You'll have to bring the game to a physical location to do this. I can't imagine any physical stores even selling GB games anymore, let alone providing a service for said games.
    – Nelson
    Feb 22, 2015 at 22:01
  • 4
    Perhaps a local game store or a repair shop can help with that. If it's not officially stated as a provided service, doesn't mean they can't provide it. Ask around. Feb 22, 2015 at 22:18
  • 1
    @Nelson backup saves, change battery, restore saves Feb 23, 2015 at 0:33
  • 1
    I meant safer for the game boy and the game :) Of course you can't really hurt yourself much with the GB, unless you did something monumentally stupid, like swallow something.
    – Nelson
    Feb 25, 2015 at 3:02

The accepted answer is flat out wrong, problems with it include:

  • It will be very difficult, if not impossible, to access the cartridge while it is inserted into a Gameboy. It will be easier with a Gameboy advance as it will stick out some.
  • Gameboy cartridges are very difficult to open; they use a proprietary screw that is exclusively used by Nintendo. A specialty tool can be obtained from specialty suppliers, but they are necessarily pricy.
  • The battery back-ups in Gameboy carts are soldered in, you cant replace one without a soldering iron.

So even if you bought the tool, disassembled the cartridge and inserted it into your Gameboy, your not going to be able to de-solder the battery and solder in a new one!

If you want to replace the battery you will need to power the volitile memory with an external power source while you change the battery.

Years ago I tried replacing the battery in a Gameboy cart. I did a lot of research to find the correct replacement battery and read the tutorials. I had to cut it open because i didn't have the proper tool. After I replaced the battery the save file still didn't work. In my case it may not have been the battery.

I suggest you try this with an expendable cart first, or find/buy a way to get the save off the cart first.

  • Esoterik is right. I remember opening my GB carts and the battery is soldered, so there's no way you can safely unsolder a battery while it is powered, since you will need to use heat sinks to prevent the heat from damaging connected electronics.
    – Nelson
    Feb 25, 2015 at 3:11
  • Wow, thanks for clearing that up! Some questions: 1. So the save and effective way would be combining of buying the hardware to transfer the save between PC/memorycard and game AND to do the tinkering? 2. Are most of the batteries soldered or are there many exceptions? 3. Do you have any short versions of how-tos to replace the battery? That would be an answer to my former question, as this answer replies to another one. :)
    – Trollwut
    Feb 26, 2015 at 13:50
  • @Trollwut 1. yes, save then repair would be the safest, or get a cart you don't care about and practice. 2. As far as I know most are soldered, but I have seen a pic of a game boy color cart that looked like it had a batter holder/removable battery. If they switched I don't know when. 3. google finds a few, but I don't have the time to read and recommend one.
    – esoterik
    Feb 26, 2015 at 22:23

Technically what you need is that the memory unit to be constantly powered by some electricity. So what you could do is use some wires connecting the + and − contacts on the cartridge to another battery while you take out the old one and replace it with the new battery. So for this you have A − the old battery that is running out of juice, B − the new battery with full capacity, C − the secret hacky battery connected to the cartridge with wires, which do not obstruct the process of replacing battery A with B.

I never tried this myself, so it might not even works because of too much voltage in the two simultaneously connected batteries (B + C, because B is at full charge, and C… enough to keep the save alive), although it should probably not cause any harm if you use the battery C with less than full remaining power. That way the total sum of all battery power (first A + C, then B + C) should not reach 200% battery power. This is all just a theory, but from the sound of it it's basically the same as changing batteries while having the cartridge powered on by a working Gameboy.

  • 10
    > too much voltage in the two simultaneously connected batteries (B + C, because B is at full charge, and C… enough to keep the save alive) No. You're connecting in parallel, so you'd end up with the average voltage and a larger current capacity. It won't directly harm the device, but it can harm the batteries involved (since you're effectively going to partially charge the old battery with the spare one, which will also discharge the spare one faster than it's rated for). Probably not an issue if done quickly, but both batteries involved should be binned afterwards.
    – Bob
    Feb 23, 2015 at 5:23
  • Possibly if the "hacky" battery is a lower voltage but still able to keep the RAM alive on its own, this could work. This ultimately depends on what the tolerable voltages are for operating Game Boy battery backed memory. As these voltages are likely to be proprietary information, most probably you will just have to guess, unless someone has such information that I think right now is more likely than not "proprietary!"
    – user232276
    Jul 20, 2019 at 21:01

Buy a Mega Memory Card.

I am surprised nobody answered with the most practical answer yet.. Copy your save onto the Mega Memory Card, then copy it back after the battery replacement.

I also heard of a more complicated solution involving connecting the new and old batteries at the same time.

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