Game Boy With Lithium Batteries And USB

[Alan] procured a few Game Boys from a Yahoo auction with the intent of using them for some other projects, but one of the Game Boys was shipped with a very corroded battery which had eaten up one of the terminals. When [Alan] had repaired it, he was left with a Game Boy with no battery terminal at all, so he decided to splice in some lithium-ion batteries.

Not only does the Game Boy now have a new battery pack, but [Alan] was able to source a USB charger to handle the batteries’ charging needs. However, he realized that his battery pack was 3.7 volts, while the Game Boy only needed 3 volts. To lower the voltage of the battery pack to the required voltage, [Alan] grabbed a 1N4148 diode and put it in series with the battery pack, which also helps prevent any accidental reverse polarity.

This isn’t the most technically advanced Game Boy hack we’ve ever seen but it’s great to see new life breathed into these classic video game systems. Not to mention that [Alan] saved some lithium batteries from the landfill!

21 thoughts on “Game Boy With Lithium Batteries And USB

  1. I wonder what the game boy’s allowable input voltage actually is. I’d assume there’s a switching regulator in there somewhere (probably step-up based on the age) so it might be able to handle 3.7V.

    1. You are correct about the switching regulator. Apparently, it can regulate voltages up to 12v. The issue with doing this to the original gameboy is that the LCD contrast signal (-19v) is unregulated, so the LCD might be damaged over time, but it appears that the gameboy color uses a completely different regulator. I’ve run my gameboy color at 5v for several hours with no problems, so 3.7v should be safe.

    2. U5 is the power supply (chip/module?) +5V, -15V and 13.6V output
      Given that the module has higher voltages, so chip process/discrete parts can handle higher voltage. It is likely that going to 3.7V might not be an issue.

      However, Li-ion normal voltage is 3.7V and can go as high as 4.2V right after charging or when used during charging. To Handle situations like that, might be safer to use a real LDO instead of relying on a diode drop.

  2. USB Charging you mean.
    Title implies USB connectivity, at least to me.
    Still GREAT to see another Gameboy hack as I just rebuilt a Gameboy Color for my own collection and it is a topic of interest.
    Now hack this into a GB Boy Colour! lol (look it up)

  3. That’s funny, I am restoring one of these right now (scratched case and busted speaker due to corrosion). Just this morning I looked online for parts, so while I was at it I looked into ways of lighting up the screen and considered adding a rechargeable battery for longer runtime.

    I really hope that battery has built-in overdischarge protection, though. Because if it doesn’t, nothing will stop the Game Boy from sucking it dry. And once it gets below 2V, recharging it can be dangerous…

  4. well i did a similar mod over two years ago. if anyone wants to give it a try.. here is some advice the gameboy dc-dc converter can handle anything from 1.9-5.2v under load. there is no need for a diode. I originally was worried about the working voltage too but i’ve tested the voltages since then and i can run that high. But if you are ever going to use a li-ion battery make sure that it has a battery discharge circuit is present. And if you want to charge and play at the same time you need to share the load on the battery in order to not disrupt the battery charging circuit. anyone interested in this should look up “load sharing battery charger”

    Here is a example of what i did a long time ago.

      1. If he looked around a bit more he should have found the chargers with the same chip as the ones he has but with the extra over discharge and over charge protection.
        He’s apparently in Japan though.. So if he goes to somewhere like strawberry linux he can get a charger based on a decent chip (with under voltage lockout) next day in the post.

        1. I’m trying to figure this stuff out without knowing much… Can you point the way to the charger you describe? I’ve found two separate tiny little units, one charges and one protects, but I would obviously prefer the all in one unit.

  5. does anyone know if the kung feng gb boy colour have this switching regulator thing? i dont know anything about electronics but i have found this to look easy with the help of tutorials :)

  6. I would really like to do this mod to my old DMG. could one of you please send me a message to with suggestions on what would be the best charging circuit to buy for this kind of project. also i was thinking would it be ok to use 2 3.7v li-ion batteries in this for extra long life and if so how would i need to wire that up? thanks to anyone who wants to send me some tips for this.

  7. I am modding my GBC starting with a lithium battery taken out of a portable recharger. Its a 3.7v and 4.6Wh. Comes with a USB and mini USB port. I plan on routing power from the USB port because thats how you charge devices. If anyone has any tips, tricks or things to look out for, let me know please. I’ve never done soldering but its a good time to start. After this I plan on changing out the screen and adding internal memory.

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