Flat Battery and hot cable

[gazwilson]

Hello, Hopefully one of the master tech's will be able to help me with a battery issue with my A6 2006 2.0Tdi saloon. I could not start it this morning - battery flat and the RAC came out tonight and got it going for me. The battery checks out as good but there did seem to be some loss of charge - 14volts leaving the alternator and 13.4volts at the battery. The patrolman suggested that I take it for a drive but I noticed that the big Positive terminal with the red plastic cover on the drivers side inner wing was getting hot. He suggested that I get the vehicle recovered to a dealership which I am intending to sort tomorrow. I just wondered if anyone had any thoughts on possible issues even though it may be a needle in a haystack.
Thanks
Gary

[gazwilson]

Just in case anybody has a similar issue - Main dealers diagnosed dead battery that was not taking the charge so wiring began to heat up. They replaced battery and all seems well - just shows RAC diagnosis is not always 100% even though they did their best.

[hravey]

Time of year for battery probems on any vehicle. You use lights, heater, wipers etc which all take the most current, plus the cold will show up any dodgy cell in a battery. however this explanation sounds slightly off to me. A cable will heat up only if it is taking more current (amps) than it can handle. so the alternator wont try and push the current through if its not being accepted for example. I'm not saying it wasn't a battery problem just maybe not how it was explained to you. But then again i'm no professor and with the amount of electronics on a car now, anything is possible

[gazwilson]

Yeah, thanks for your interest

I suppose anything is possible and it didn't sit squarely with me either. However, the issue is undoubtedly solved by the excellent Blackburn Audi team - no starting problems or hot cables! so that is fine by me even though I paid for a new battery....incidently they did give me an excellent deal and a 40% contribution from Audi.

All's well that ends well and all that stuff.
Cheers
Gary

[hravey]

Quite right. the out come is most important. Do you deal with blackburn often ? Are they reasonably priced ? I have a few problems with an A6 Which I have posted about under the title flasher and other problems (something like that), but not had a reply yet. I haven't had the car long and i have had company vehicles for 12 years now so haven't a clue what is reasonable and what isn't anymore

[gazwilson]

I have had my A6 since October and they have done their utmost to sort out some issues that I have had. Granted these were under warranty until December but I have found them most helpful - especially Rebecca on service reception - and reasonably priced. No main dealer is going to be cheap but there is a peace of mind issue there too and I have had enough dealings with them recently to have formed a very positive opinion. Hope this helps.

[hravey]

Thats most helpfull.

Thankyou

[daycartes]

Hi even before I finished reading your post I was pretty sure of the answer. Alternator output sounded reasonable, but hot terminal means high resistance (and therefore bad connection) between the terminal and the battery connector. Solution; remove connector clean and smear with good ol' vaseline and refit. Of course no-one can be sure in these situations unless they see the actual fault but thats what the symptoms suggest.

daycartes

[gazwilson]

Thanks

The Audi main agent checked the battery and said that it was only taking about 10% of the charge. They diagnosed a dead cell in the battery and replaced it. I suppose taking off the terminals and replacing the battery would have the added result of ensuring a good connection but the connections did seem to be okay anyway. The new battery seems to have sorted the problem so I'm Okay with the solution.
Thanks

[singhl]

If you have MMI and sat nav - then ther can be a fault in that software that discharges the battery and the "battery manager" can also have a fault in its software that can discharge the battery.

It happpened on my 3.0tdi quattro A6 - both bits of software were updated by AUdi to the latest and it has not happened again in over a year - and I still have the same battery that was being discharged in the car.