A N810 will actually reject 5.00V. it accepts 4.2V - 4.8V and 5.2V - 10V or so, with varying current profiles (a 10V 1A charger is rejected but 10V 0.1A might be accepted).

The dc adapters are labeled 5V, but they actually give out somewhere between 5.2 and 8V. 5.8-6 is the most common I've seen.