Cooper s Flat Battery but now won't start on a jump!

[Lordbenny]

So, after spending the morning messing about with the Mrs' stereo head unit I go to start the car and I get the dreaded clicking!!!

So, assuming a flat battery i hook the car up to my Passat and after 5 minutes charging I turn the Mini over. It seems to turn over fine but won't fire up!

The battery light is on and the car still just clicks when not hooked up to the Passat. I've put the battery on charge till the morning.

My questions are....even though the battery is flat why won't the Mini fire when hooked up to the Passat and turning over? Do you think it'll be fine after a charge? Are there any strange ECU type issues after a battery has gone flat?

[Dr Interceptor]

Depends which MINI you're talking about...

2001-2006 R50/R53 - I don't understand why it wouldn't fire
2006-2015 R56 etc - they are bizarrely complicated and a flat battery can cause all sorts of issues even if they are hooked up to a decent power source.

[hyperblue]

My R53 used to take ages to get started when hooked up to another car, needed a fair amount of revs and some time for the battery to have enough juice.

[Lordbenny]

The problem was that, yes, indeed it did more charging than just a jump from the Passat. After an night on charge it's now fine. Thanks for your replies.

[Bokers]

Get a new battery it will die when it gets cold again.