I ran into the following post at RCGroups which describes a potentially critical error condition with the 3DR power module.
I cannot verify the claims but at least they appear well founded so I'll leave it to the tech guys to comment on that.
Post by jabram:
These folks over at DIY Drones did not mess with the pins
They did experience a spike when disconnecting Lipo while performing ESC calibration of all ESC at once.
How does one assemble a multicopter without messing with pins ? CANT BE DONE -
Disconnect Lipo BEFORE messing with any wiring.
Check, double check, triple check you wiring modifications carefully, VERY CAREFULLY before connecting Lipo
DIY Drones Power Module that you have faith in is a primitive amateur design.
I do not recommend anyone use the DIY Drones Power Module.
The switching regulator chip 3DR use in the simplistic amateur design Power Module is only rated at a Maximum input voltage of 18V, The manufacturer of the chip ONLY recommends it for use with a 12V input supply, hence my "amateur" comment, they did NOT read or did not comprehend the datasheet..
It is extremely easy for a Lipo spike when connecting or disconnecting it to exceed 18V, specially when using a 4S Lipo and can also easily occur with 3S Lipo