Rechargable Game Boy Color

[ADemoGuy]

Hello. If I'm posting in the wrong place please excuse me but I would greatly appreciate it if someone with an electrical engineering background could double check my work.

 

So, I recently purchased a GBC (Game Boy Color). I have already given it a backlit screen mod as it's simple and well documented online. Now the batteries it came with are dying and I want to further mod the GBC with rechargeable  batteries. Sadly there isn't a lot documentation online for rechargeable battery modding a GBC. Anything I could find used lithium batteries.

 

For anyone unaware the GBC typically uses two standard AA. Therefore if I want to mod it I should need a battery at 3 volts.

 

Any sane person would purchase a lithium battery and buy a simple charger, then call it a day. Unfortunately I'm not sane. I have two NiMH (Nickel Metal Hydride) batteries from an old Xbox controller rechargeable batteries pack. I want to use these to mod my GBC. the batteries have no text on them so i'm not 100% sure of their specs but a sticker leads me to believe they are 1.2v, 350mAh (the amperage seams way too low for their size) each. I'll include a picture of the batteries.

 

When I go looking online I only find a few old charging boards for NiMH batteries. Though, this makes sense as it's an old technology. The problem with this is that none of the available ones have USB charging and any power out (that would run to the GBC. Of the available chargers this one is most promising: https://ebay.to/3biH7AT  

I would be very grateful if anyone is able to find a charger that is better and share it with me. Just remember that it has to be very small.

 

My main questions are:

1. If I was to buy the above mentioned charger would I be able to also buy a female USB type C port and wire that up to the charging ports. As far as I can tell any standard phone charger should be able to charge it.

2. Because the charger has no power out, would it be possible for me to directly wire the two batteries to the GBC. I believe it should work as standard rechargeable AA batteries seam to be very similar to the ones I have.

 

Thank you in advance to anyone that helps me out.

[fordy_rounds]

A couple of notes: when batteries are placed in series, voltage multiplies, capacity doesn't. So each battery is 1.2V (which is normal for NiMH; voltage is actually a direct result of the battery's chemistry, so all NiMH cells are nominally 1.2V) and 700mAh, and together they are 2.4V, 700mAh. That does seem very small though. AA cells are typically around 2400mAh, and AAA's are around 1000 (so this is much closer to 2 AAAs than 2 AAs).

 

As for the charging board, it looks like it might work? It's unclear whether it can output 2.4V (charging in series, the ideal scenario) or only 1.2V (you'd have to wire it in parallel, which leads to potential problems with charge balancing), and also whether it can remain plugged into the batteries while they are discharging. But it will take a 5V input, so wiring a USB port wouldn't be hard; I'd recommend micro- or even mini-USB over USB-C, though, for ease of assembly.