"Maybe, but when I look at the schematics with your hypothesis (+5V from the battery on the signal line, batt GND on the 5V board pin), this means that the PH5 (pin 17) from the AT Mega would have a +5V. This part should be also fried. And the TI…"
"Hi there,
As I explained in an email to 3drobotics today, I just fried my APM 2.0.
To make it short, the board was working, tested on usb first, then with a receiver and just a ESC+LiPo plugged to OUT3. Everything worked fine, even the Xbee…"