GBA SP battery in GBC questions

[thaddius]

I've followed Bibin's tutorial on how to install a GBA SP frontlight in a GBC (thank you Bibin) and installed a switch to overclock my GBC (I adapted this tutorial to do so). I was going to do a prosound mod, but I seem to be running out of room on the inside of the GBC. Anyway...

Now I'm looking to install a rechargeable battery, namely one from a GBA SP. I read a couple of posts on this site about how people have done this (like this one). I want to do the same thing, but I'd like to know if it is possible to make it so I can charge the SP battery within the GBC (as opposed to the external method used in Bibin's rechargeable GBP that is).

I already have:
-GBA battery
-GBA battery housing
-GBA battery contacts.

I'm aware I need:
-a charging circuit to regulate the charge going into the battery to prevent overcharge, etc.
-a means of charging (someone named Spazmonkey mentioned here the use of a mini USB port)

Now for the questions.

-Where the hell do I get a charging circuit?
-How do I know what specifications I need for said circuit?
-Are these parts salvageable from a GBA SP?
-How do I wire such a device?
-Is this too many questions?

[thaddius]

Ok...

So I found this charging circuit for li-ion batteries on DealExtreme and assume that'll do me fine. I'm going to probably buy a replacement charging socket for a DSi seeing as how I have a few chargers for it lying around.

The only problem that remains (apart from knowing if the charging circuit is what I need) is how to wire the charging socket, charging circuit, battery and GBC together. I can't seem to find clear instructions on Google.

[Deadboys]

I'm fairly certain you won't find a step by step guide by any means, but i do know that you could probe in obvious places with a multimeter and see where the gameboy draws power from the batteries, its pretty obvious too, just check the leads from the battery compartment.

[John92]

Did you make any progress with this?

I'm looking to do this too.

The circuit you linked to is just a protection circuit, and doesn't actually do any charging. Did you find an actual charging circuit?

I'm also wondering how to convert the 3.7 battery to 3.0 volts...

[thaddius]

Did you make any progress with this?

None so far.

I'm contenting myself if the frontlit screen and overclock switch, but the battery thing is on hold due to the fact that I have no idea what I'm doing.