Hello

I know you have said you don't want to have a custom case, but quite honestly I find the drill battery case bulky in most cases. Their square shape would also make it hard to find RC lipo's to stick inside?

I did some very rough designs quickly of what I would do in this case. The bottom tray would be made from 1" delrin (Offcuts from big companies can be had for cheap on eBay), and milled out, couple of holes drilled, press/glue in your male bullets, probably take all of 30minutes depending on how big an endmill you use in the delrin. For the batteries you simply make a little delrin block housing the female bullets and would then be soldered on to the lipo wires. The block would probably require some hot glue/silicon and then heatshrink over the both it and the battery to be rigid enough with a soft pack lipo. Hard pack lipos mostly have the bullets already so no need for the block.

Problems with the design would be you still need some sort of strap to hold the battery, but something could be designed there quite easily I'm sure. Also for the best possible alignment when inserting the battery should only just fit in the tray. That means if you use different capacity batteries regularly, it probably won't work too well. That said if you only have one type of battery, doing the mill work yourself, it would probably only cost about $30-50 in material depending on how many batteries you want to 'convert'?

EDIT, looks like chris mechanic beat me to it!

Interesting idea, I shall be watching to see how you solve it

Kieren