Need help with LiPO batteries
We have used LiPo in parallel successfully. Parallel cells must have the same batch #.
When charging, use a voltage regulated source set to (slightly less than) the 4.2 volt cell charging voltage.
Look at a DC-DC converter with a current limit at 1C (240mA)
So you need a modular DC-DC converter for rated at 400mA, at 4.2V. The upright-PCB ones are available from RS etc...
you can use it in parallel, and this does make things more complex. And depending on how long your robot is supposed to run for will decide if its right or wrong for your application
you can charge them in parallel but you will need a 2 cell charging circuit
I wish i could help you with this circuit but, but thats over my head
here is one from spark fun 1000mAh - link this one has the protection included, other places to look would be place that sell micro heli replacement parts