CleanJuice Air Game Boy Color Wireless Rechargeable Battery Module - RetroSix

Works great so far! I used a Retrosix Prestiege shell and it was a simple fit. I highly recommend watching the manufactor's video on installing it (see the url I've included) to help with the subtle parts of alignment. Mine did not come with double sided tape for the battery, so it's good to have some on hand in case.

I'm planning on doing charge time tests along with run-time tests to see how long the battery takes to charge and deplete. Will report back when I have my results :)

UPDATE: Did some tests and have results! After fully depleting the battery (which took SEVEN hours, so there's a good initial charge), I found that with the volume fully up and with full brightness on my IPS v2 screen that my Gameboy gets 11 hours of playtime. Charge time takes around 2-3 hours using the Qi charger available on HHL's site. I'm sure there's better chargers, but this one does the job. It's very picky about where the placement is.

I HIGHLY recommend when charging it, however, that you remove your game cartridge. Since it's wireless charging, things get hot quickly, and my game cart was uncomfortably hot when charging was complete.