Wife was backing out of a parking space, put it in drive moved a few feet and everything went dead. No lights, no click upon ignition, no horn, nothing.

Tried the only thing my non-automotive mind could do, which is jump starting, with no results.

I did decide to see if the Mini battery had any juice by doing a quick touch of the + / - cables and there was indeed a nice arc.

I have read every thread pertaining to this type of an issue going back to the beginning of the year, but do not feel that any of the suggestions fit this situation exactly as the power died while the car was running and in motion.

We have had not problems with the battery to this point. Please help.

 

I am thinking a bad BST cable. It is the positive cable that comes off the battery and out the grommet towards the front. Right near the cable there is a black junction and IIRC with a orange connector plugged into the bottom..Anywho, in the event of an accident, the junction seperates cutting power. Easy to check, probe for 12V after the black junction point. Don't have it...your BST is bad

 

Problem resolved.

It was corrosion of the connections at the 200 amp mega fuse near the battery terminal.

However the root cause is still to be determined as the battery box in the hatch had a substantial amount of water in it! I will create another post to seek input for probable causes.

 

That's the idea...got power at the battery, follow it until it stops

Great job