Installing an Internal NiMh Battery Charger in a Game Boy Advance (Part 1 of 2)

but you can use any charge port or other ~5v input that you want.

It does get VERY hot but I haven't had any issues yet. A better location would probably be under the cart reader shielding then you could probably add a little bit of thermal interface material to connect the IC and just make sure to remove any inserted games while charging. The metal shielding could then act as a heat sink and it would be exposed to circulating air rather than the stagnant air inside the console. Or, if nothing else, at least provide some extra thermal mass. The only downside to this is that the indicator LED would have to be relocated. I think moving it over near the power LED might be a good idea though since the power must be off while charging anyway. That would work for opaque shells too.

Oh and yes, this does still work fine with alkalines. Just don't try and charge them.

[jimmybrad]

the cn3085 datasheet says that in sleep mode (when the usb c isnt plugged in), drain current drops to less than 3uA, which should take about 5-8 years to flatten the cells.

[christhompsonphotography]

I have a Joytech GBA battery grip and was hoping to swap the expired batteries out for NIMH batteries. I have to check what style the batteries are first.

[esotericsean]

Beat me to it! Finally got a hold of some of those boards and planned on putting together a video for GBC.

[smurf]

I love how you have a Sims cart running Pokemon Gaia

[jimmybrad]

You could probably change the value of one of the resistors on the board (should be easy to look up on the net) to make it charge a little slower so it doesn't get quite as hot.

[harisuresh]

Is there a 6s version for 6 batteries in series?

[daijoubu]

As for the heat, since it's a linear charging IC, it will dump quite a lot of heat from 5V to the 2-3V used for charging at 1A (2-3W?) Into a small SOP8 package, I guess you could lower the charge rate and/or add a small DC-DC converter to drop the input voltage to like 4V as the min input voltage is 3.8V

[daijoubu]

Looks like it's based off a CN3085 and if I understand the datasheet correctly, it's CC until a set voltage (divider on FB pin) then goes into a trickle charge with a time limit set by the RC pin, so it's not ideal and may under or overcharge (granted wont explode but may shorten the life) and LSD NiMh (Eneloop and LADDA alike) doesn't like being trickle charged, I'll check the module charge termination voltage and time limit, some of those implementation are very dodgy. Also, may want to add the NTC if not present.

[daijoubu]

As for the quiescent current, it claims 3uA in sleep mode, so shouldn't be a problem.

[pnox]

Hi, i'm trying to find a pcb for nimh charging, play and charge capable, but i can't find the guy you said on the video who was making a nimh charger for the game boy.
You have some recommendation, from the one of the video?

[SuperLuigiGuy]

Best site to find used gbas on the cheap? 🤔

[daijoubu]

So yeah with all those caveats, the elcheapo TP4056 really shine as it properly charge lithium cell using CC/CV with C/10 termination, there appear to be another chinese NiMh black charging board, switcher probably because of the inductor and diode but only handle 240mA...slooow may as well gut the Ikea USB charger which claims dV but with a timer failsafe, it's hard to detect dV at such low charge rate anyway.

[daijoubu]

I still prefer lithium ion, if you're not a fan of lipos from a safety stand point, but charging NiMh is best done individually, unless the cells are matched, also, are those modules charging them properly with a delta V termination? For 2 cells... I'll just take them out and put into a proper external charger lol, now if it was the DMG with 4xAA...now that's getting annoying. Or 3xAA/AAA also very annoying.

[pscustomgamer]

EDIT: Resarching this a little more r3 can be changed(easier said) to vary the charge current 1.21k 1000ma, 1.5k 800ma, 2.4k 500ma.
These state they can charge at 1amp and I dont trust charging eneloops past 500ma which are theoretically the best nimh

[TheDailyTeacherTuey]

Would you be able to put a schematic up of how you wired your LiPo tp4056 rechargeable? Also what components did you use? A 1n4001 diode? Basically, are all the videos on YouTube for the diy LiPo done correctly?

[mike]

where did you get the controller board with the usb type c connector?

[coldfire]

hey bud, you had chance to upload the files for the usb c connector

[robert_wolf]

Hey @makho. I successfully completed this mod just like you did in the video. Thank you btw. However once I charge the batteries fully. If I unplug it and plug it back in. They start to charge all over again and it takes about an hour for the light to turn back off. Is this normal ?

[JesusRodriguezCisneros]

Brilliant mod; I see myself charging my AAs with my GBA when I won’t find my battery charger xD

[jonathanmsantos]

This idea gave me another idea: why not put a TP4056 in the same spot? and make Lipo removable battery with JST connector? then you can also disconnect battery and still use AA batteries. Tried it last night and it fit snugly in there. That is why i love watching your videos, thanks