If you are having battery issues, or the eDGe does not power on when you press the power key:

Remove AC power and pull the battery out. Replace the battery and insert the AC adapter. You should see the power LED start blinking green to indicate it is charging. Pressing the power key at this point will turn the power LED solid green and the eDGe will boot.

The EE battery charges to 100% in ~2hours so long as you stay above ~5% charge. If you truly exhaust a battery by using it until the eDGe forces a power off, then leaving it in the eDGe (because the low level power control circuitry is still running) for a long period of time without a charge, it can take up to 12 hours to go from 0 to 100%. It takes about 10 hours to trickle charge an exhausted battery to get it up to an acceptable level (~5%) to ensure we do not damage the battery. Once we hit 5%, we can charge the rest of the battery very quickly. This is something to keep in mind if you experience the EE taking an abnormal amount of time to charge.