please take note that i did this when i was very young. the charging methods i used in this instructable are highly dangerous. a better route to take would be to extend the leads from an ipod (in this case an ipod mini) to a port that would connect to the dock. NEVER CHARGE LI-ION BATTERIES THROUGH A WALL CHARGER! CHARGERS LIKE THESE ARE MENT FOR NI-CAD TYPE BATTERIES! li-ion batteries CAN EXPLODE if left unattended.
My dad gave me his old wireless keyboard and mouse because his old mouse wouldn't hold a charge for very long. I have been looking into a wireless keyboard and mouse for my notebook but prices are not in my range as of right now ha. So i took his and began looking into the manual for it when i saw that it could also run on 3AAA batterys. Yeah, that could be easier to do, but i don't want to go and buy batterys every time the mouse runs out (which is why i want rechargeable, duhh) so i have 2 options. 1-get rechargeable batterys and link them together so they could be recharged on the dock or 2-find something else that could be used as a battery.
Step 1: Prep
take out the battery case and remove the battery, then remove batterys
Step 2: Getting the New Battery...
i decided to use a ipod mini battery that i had laying around from all the ipod parts that i have. i cut the black and red wires, extended them, and then wrapped them around the appropriate metal tab.
Step 3: Finishing Up
place the battery into the existing case and close up. Finally, test the mouse!
i let the battery run out just to test if it recharges. the following day,l i put it on the cradle for a few secs and it worked. i'll update to give the full battery length.