In addition to the micro USB and J21 power options, you can also connect a single cell lip to J2.
J2 is connected to the TI BQ24074 battery charge/power management IC (http://www.ti.com/lit/ds/symlink/bq24074.pdf) that is on the mini breakout board.
I suggest that you use the micro USB connector that is closest to the J21 connector to power the board - until the Intel engineers confirm that it is safe to use the 7-17V input.
In case you decide to connect a Lithium Ion or Lithium Polymer battery, please make sure that you know the correct polarity (it is not marked on the board) and how to connect the NTC temperature sensor that is in the battery.
I am questioning if the power converter that generates 5V from the 7-17V input is designed so that it can handle the maximum load, and especially the load transients that can appear when using the USB output and also having a battery attached (so there is charging current and also there may be inrush currents to loads that are connected to the USB port).
My concerns are based on just looking at the inductor (looks like an 0805 type inductor to me, in which case it probably is not able to handle more than 1A, while the circuit is certainly able to generate 5A short term) and looking at the resistor that is in front of the buck converter. It is a 0402 size 0.10 ohm resistor which means that its power rating is only 1/16th of a Watt. so if it is a standard type of resistor and nothing of alien origin, it is not able to survive the maximum currents that can appear during transient conditions.
this is only of interest to people that hook things up to the Edison, so don't be discouraged. I am just not receiving any response from Intel engineers. I want them to tell me that I am all wrong and this is how the thing is working, and I just have not received any attention or response. I am still waiting.
in the meantime, I think that by me posting my concerns I may help some engineers that where just going to copy the Edison breakoutboard design from loosing the farm, just in case I was right in my suspicions.
There's a difference between it being safe to power via the 7-17V connector and the ability of the board to power external devices. I don't think there's any issues with powering the board, but there might be an issue with high-current USB devices.
Does the Arduino board share the same regulator design?