I've now assembled a custom battery for my GP2X made out of three 3.7V 800mah Ipod 4th generation lithium polymer batterys and benchmarked it. It lasted 5hr10minutes playing DrMDX at 200mhz with the sound on (used the looping xenon 2 demo for it so it was mostly a full load all the time). I'm not sure if the battery was fully charged mind but it must've been fairly close to full, I'd say 80% or above.
To create it I connect the three batteries together in parallel and connected the positive and negative wires to the battery contacts on the unit to ensure it worked (which it did). I then bound the three batteries together using insulating tape.
The battery won't fit into the compartment as it is so I took off the back case of the console and using a slightly serrated kitchen knife (a jr hacksaw simply can't get in to cut it) and a file I cut out the grooves the AA fit into, removed the back contacts and filed the battery compartment until I had enough space to get it in. It now fits snugly into the battery compartment (although you have to remove the back cover to put it in or take it out and the console can no longer take AA's) and the battery cover still fits over it and covers any uglyness.
At the moment I'm using two wires which are wedged up against the battery contacts to connect the battery up and to charge it (using a special charger which connects by crocodile clips). However it's going to have some soldering work done to it (the wires connecting the three batteries together are joined in a pretty questionable way) which will also esnure a good solid connection between the contacts so the unit doesn't reset everytime it's jolted and the battery and to ensure I can still charge it without having to take off the back of the console every time, just the battery cover, I'll be attatching some copper ribbon to it too.
haven't got any pics at the moment because I don't have a camera on me
To create it I connect the three batteries together in parallel and connected the positive and negative wires to the battery contacts on the unit to ensure it worked (which it did). I then bound the three batteries together using insulating tape.
The battery won't fit into the compartment as it is so I took off the back case of the console and using a slightly serrated kitchen knife (a jr hacksaw simply can't get in to cut it) and a file I cut out the grooves the AA fit into, removed the back contacts and filed the battery compartment until I had enough space to get it in. It now fits snugly into the battery compartment (although you have to remove the back cover to put it in or take it out and the console can no longer take AA's) and the battery cover still fits over it and covers any uglyness.
At the moment I'm using two wires which are wedged up against the battery contacts to connect the battery up and to charge it (using a special charger which connects by crocodile clips). However it's going to have some soldering work done to it (the wires connecting the three batteries together are joined in a pretty questionable way) which will also esnure a good solid connection between the contacts so the unit doesn't reset everytime it's jolted and the battery and to ensure I can still charge it without having to take off the back of the console every time, just the battery cover, I'll be attatching some copper ribbon to it too.
haven't got any pics at the moment because I don't have a camera on me