Hi. This is to just let every on know what I've found out using the LIPO's
Here is what I'm using to power my robostix+gumstix400-xmbt+netMMC.
I got about 2hours 45min with this battery:
and using this switching converter:
You could probably also use the fixed 5v converter.
I think the switching converter is what limited me. because it has a
1.3v drop out it will stop powering the board once the LIPO hits about
6.3 volts which is about when you want to shut them off anyways so you
don't over discharge.
Also I had everything on. I was powering both the Bluetooth and the
Ethernet. I imagine I would get more time if I wasn't running the