Quick bit of help if poss from vagcom users

[lengster1]

Im about to travel back to uk in my b6 tdi,battery warning light came on today grrr ive scanned it but no faults,i get an output reading of 12.08v at idle dropping to 12.1 @ 2000rpm,seems its charging but not at 13-14v as it should,lots of dark dust particles in area possible from the bushes? Would the low output trigger the warning light? Would you chance 5 hrs driving in it if i cant buy a new one and get it fitted tmrw? Dilema grr sorry for posting it in here but need a decent responce if poss and quick

[Batfinnk]

Sounds like the alternator. My old A6 did similar and kept bouncing up and down. I wouldn't chance that drive if you can get it done beforehand tbh.

[MikeFish]

+1

[rs4Mav]

Would you chance 5 hrs driving in it if i cant buy a new one and get it fitted tmrw?

do not drive, the battery will go flat in no time.

[lengster1]

You reckon the 1or 2 volts lower charge rate would be that much of an effect? Lets see what it reads tmrw on the meter and see if anyone local has one on stock, contemplating buying a new battery as a back up to get me home if I cant source alternator before lunch.Hmm ferry is already booked grrrr doesnt it always happen when you least need it!

[Batfinnk]

My A6 when it went just about managed a 20 min drive before the lights were dimming badly. Don't forget these cars use the battery so much more than the old days. You would need about 10 plus batteries to make the journey tbh. Not worth the risk one little bit tbh.

[MikeFish]

I don't think it'll drain the battery that quick, especially if you are selective about the electrics you are using.
A spare battery will obviously help, especially if new. Just make sure you have the right tools to change it including any bolts holding down the battery, normally need a socket set with extension on most cars. Can't remember what our cars need. Isn't the clamp behind the battery rather then the more accessible front?

[MikeFish]

Ps should add that I still recommend fixing it first though.

[lengster1]

Hopefully i can get one tmrw,if not il get the avionics boys to try and calculate how long it will last with its current low output,il need lights for last two hours so could be a tense journey !!

[MB2]

Car alternators these days tend to be "smart" sdo they only deliver the voltage needed by the battery at that moment in time so be cautious interpreting alternator output figures. I would also check the wiring to the alternator as I once fixed a Ford Ka that had similar issues by repairing a wire that ran to the alternator - the garage had said was over-charging, in use the battery went flat - new wire & worked perfectly. I know not the same car but thought was worth a mention - on the KA was the wiring in the plug going to the alternator that had failed.

[lengster1]

She has a new bosch one fitted

[MikeFish]

Better safe than sorry eh!

[steveyb]

Had a similar problem with my other car (Golf). In this case the alternator was overcharging (16.6V) and had caused the airbag light to come on. Instead of swapping out the whole alternator, I changed the Voltage Regulator, this is part of the alternator and is a simple swap. It cost me just £15 instead of the £185 for the complete alternator.

[lengster1]

Yeh i also tried that first,we removed origonal to check the brushes and when re installed no warning light so thought bingo and bought one,should of checked output though because after a new one was installed the ruddy light came back on after a few mins.output test recorded zilch so had to cough for a new alternator,but im sat on the ferry homebound for birthday weekend and see my kids so all good ! Looking at weather reports i might leave the RS in the garage and make use of the snow tyres on the tdi.