Hi. Newbie here. 

1. I gave a mate a jump start while my engine was running. Once his car was running I removed the jump leads from my battery and earth point. Instantly my car turned itself off, showing absolutely no life at all. No lights on cluster, no click on turning the key.

However after a few mins I connected the cars back up and mine suddenly had the usual lights on.

2. Another time I used a tyre inflator with crocodile clips to inflate a tyre. I kept the engine running while doing this. Then, when I removed the clips the car died. No lights inside at all. Tried to jump start it but before I got the cables connected all the lights reappeared. Strange.

3. Today, I went to my car, key in ignition then cluster lights all went out. Seemed dead. Half an hour later I went back to my car, opened the door with the key, pulled the bonnet catch to get ready to remove and charge the battery. Suddenly I heard a slight whirring noise. Then I noticed all lights in the cluster were back on, and I was able to start my car no problem.

Any ideas? I tried some searches but got nothing back.

Is there a power cut out that might have caused this?

Or maybe something to do with the bonnet open sensor?

Thanks.

Here we go again (multiple electrical & battery threads going - and probably always will?)
How old is the battery, has it been tested/charged, has this only happened since you used your car to jump start another (i.e. has it damaged your system in any way)?

Very suspicious that adding or taking leads off (jump or inflator) appears to cause a problem (damage to battery posts/cables?)

Fuse box relays, a bit like?:
https://www.fordownersclub.com/forums/topic/157584-ford-focus-2009-tdci-diesel-start-issues/

But lets not get distracted into other problems, keep the focus on yours but consider all options?