I started in July with OlinuXino-Maxi; now I received a OlinuxIno-micro.
I see there is no more 3.7 V battery support.
On ebay, I find low cost (3$) converter:
I suppose a fixed 5V (4.5 $) is more secure:
Am I right ?
I've done it with a step-down from 2 cells. It works fine at 5.1-5.2v with no load. 5v with no load drops below 5v with load and resets the board, especially when you plug in a usb device.
Do you want to be able to charge the battery too? Might be worth it to take one of these apart:
AC and DC input to charger, 5v DC output.