8 replies to this topic

[Colbo]

Hi

A while back I asked a friend to whip my car battery back onto my mini for me as I was busy working on something else on the car.
After about 45 seconds I noticed smoke and the aroma of burning electrics coming from the front of the mini which I instantly put down to the battery fitted the wrong way.
I quickly removed the terminals in the hope too much damage hadn't occurred but
On the initial inspection a lot of wires had melted and bonded together but none had actually burnt right through although I new at that point it wasn't great.
After letting things cool down I re-connected the terminals the right way round and the car started up and all indicators,lights,horn and radio worked.

Can anybody please advise how serious this job is for an auto electrician to put right or even someone very handy with electrics.I m not sure how to upload pictures but I'll try and work it out.
Thankyou

[tiger99]

Does the alternator still work? It was the thing that was taking all the current and both the windings and the diode pack will have been very seriously overheated. You should replace it even if it seems to work, as complete failure is not far off and it will take out the loom again if it develops an internal short.

The main damage should be to the brown circuit, which feeds the alternator, ignition switch and light switch, and also at least one fuse providing the purple permanently live accessory circuit. The brown wires extend from the starter solenoid area to the above mentioned items, so only the loom in the driver's side area under the bonnet and behind the dash should have been affected. But other adjacent wires may gave been melted, even though they were carrying no current.

But how could that happen? The battery terminals should be very different diameters to discourage that kind of error, and if the cables are run properly they will not reach. I think maybe yours are too long.

[Colbo]

Hi thanks for your reply and yes you're exactly right it's the brown wires that are mainly affected.
I do suspect the battery terminals are to long and think my friend just rushed in without much thought unfortunately.
I think I need to get a auto electrician out to survey the extent of the damage and hope it's not to bad.
The starter motor did work when I last turned the key but yes I think changing it as a matter of course is a good idea.
Hopefully the cost of repair won't be extreme :-😞
Cheers

[Colbo]

*Alternator

[mikal]

Your friend owes you many cases of beer!!

[Colbo]

Haha yeah he does mikal but not as many as I thought.
I had the auto electrician out earlier and he had a thorough visual inspection of the wiring loom and he seems to think as tiger99 said the damage is localised but a new alternator is a must and jury is out on my alarm and radio.
So how many beers is a new alternator,battery and auto electricians labour? 😂

[Mini Manannán]

£300 or £400's worth.  Many, many, many beers! 

[mikal]

Plus a penalty for stupidity!

[tiger99]

If your alarm and radio are still working they will probably continue to do so for a very long time. Depending on how they are designed, they possibly did not pass much reverse current. No guarantees of course as I don't have details of the innards of your actual items.