Battery Light & Dim lights

Inexperienced Joined: Feb 03, 2009 Posts: 32

Hi all, hoping someone can advise..

2000 A6 Avant 2.7T

Noticed a few times in recent past, under hard acceleration, battery
light came on, and stayed on for a few minutes then went off.

Nothing else untoward and only happened twice so put it down to gremlins..

Today popped round to fuel station, on return, battery light was on and stayed on. Also voltage instead of normal 15-16 volts it showed about 8, i.e. under half on dial.

Left work tonight and lights were dim, revving when stationery made zero difference to dimness of lights.

Would you say battery or alternator?

Don't want to buy battery tomorrow to find its alternator..

Any thoughts appreciated.

Regards
Matt

Posted: Sat Dec 10, 2011 7:15 pm

The voltage reading is taken from the dial yes?

The symptoms would indicated to me that the alternator wasn't charging properly - have you a multimeter? When ticking over the alternator should be putting 14v or so into the battery.

It's easy to get the battery tested to eliminate that.

Inexperienced Joined: Feb 03, 2009 Posts: 32

Thanks for reply. Yes, read from dial.

I have no 'tools' to test battery, how best to eliminate it?

Regards

Matt

Posted: Sat Dec 10, 2011 7:48 pm

A battery specialist will be able to put a load on it and test how it performs - this is more accurate I think than just measuring 12.7volts across the terminals.

Inexperienced Joined: Feb 03, 2009 Posts: 32

Thanks James.. Will see if I can find a localish one..

Posted: Sat Dec 10, 2011 7:52 pm

They should all test it F.O.C - just be mindful of the "Yes it's knackered sir, we have one her for £100 that will help" approach....!

Inexperienced Joined: Feb 03, 2009 Posts: 32

Thanks for input. To conclude post, took a risk and left for work Monday morn but alas battery gave up about a mile up the road. AA came out connected jump start 'box' to battery and got car started, then tapped alternator with hammer which sorted it, battery light went out and dashboard volt meter jumped back up to 15 ish volts. AA followed me to local HiQ garage who have always provided an excellent service for me. Whilst doing paperwork AA told me I could have loan car which I didn't even know was available so I left Audi at garage and AA took me to pick up loaner from Enterprise.

Anyway HiQ tested all and called me later that day to say all was testing fine and did I want to change alternator anyway or leave for now. Obviously all seemed ok so I thought it was worth a go in case it lasted another 6 months etc. Anyway picked up and within hour battery came back on and volts dropped so popped back to HiQ who kept car and fitted new alternator following day. Now all good so was defo alternator.

Thanks again for input.

Matt

Posted: Thu Dec 15, 2011 8:58 pm

Nice result, thanks for the update Wink