Watch out for possible problems with USB chargers.
There are reports of MyGoFlight DualMicro USB charger issue, as in this customer review:
"On September 20, 2015 on a flight from w95 to KAGC we loss the ipad,
iphone, and the stratus. All three will have to be replaced.
During the flight my wife observed the ipad smoking at the charger
connection. She disconnected the ipad and we started using the iphone.
Not thinking that the problem might be the cigarette lighter charger
we plugged the iphone into the charger. It very shortly it stopped working.
Still not realizing the problem was the charger we did not unplug the Stratus
from the charger. Fortunately the flight was in VFR conditions and
nothing in the panel was effected and we were able to complete the flight.
I took the apple produces to the apple store and they could not get either of
them to respond and suggested I replace them. Kal at Appareo said
about the Stratus "the USB protect chip was blown which resulted in
damage to the circuit board". The failure seems to be the charger,
a mygoflight, it is outputting 24.4 volts when it should be only
outputting 5 volts. Ignoring the financial cost this a very
dangerous. We often fly long distances and find it convenient to just leave
the ipad and Status plugged into the charger."