Read from Nic-Z in the mini-z forum that 230mah battery for Micro-T on ebay fits Dnano. Got one from automizzi. It did not fit for me without modification. Battery is $20 with shipping, and comes with 2 cells. That works out to $10 each for a 230mah battery. You have to be comfortable soldering lipo battery. I turned up the heat on the iron, and solder no more than 5 seconds at a time, then wait for it to cool.
Here is how I did the mod:
You have to break the pack into two batteries. The two are taped together, so careful not to break the tabs. Desolder the tabs. Bend the soft end of the battery down about 45 deg to fit onto chassis.
Take the circuit board that connects the cells together. Put a good scratch mark on the board with a xacto knife down the middle with and break it in half just like cutting glass. Solder the half onto the battery. This will give a good contact for the chassis. Use the other half for the other battery. Probably you could glue the circuit board down, but I did't do it yet.
Done. Battery fits good and works well on my stock car.