Dodgy Battery..?

[Pimped-Passat]

Passat-meisters....

I'm encountering problems whereby if I leave my car for more than 3 days without starting it, it will not start due to a flat battery. The period of time used to be 5 days, but it appears to be getting worse, so I guess something is deteriorating.

I've done a few tests with the multimeter and over the 3 days of the car being stood still and not turned over the volts drop from 15v to just over 12v.

In the past I have taken the car back to the dealers for them to test and they said there is nothing wrong with it. Charging OK, no obvious signs of excessive load on the battery when the cars "gone to sleep". And we've been around the loop of the radio turning itself on, etc

So my question is.....

Do you think this could be a dodgy battery that won't hold charge and is getting worse as the time goes on..?

Has anyone else with a B6 diesel ever experienced a similar problem and solved it with a new battery..?

Any help much appreciated.

Cheers
Mark

[zollaf]

try this. disconnect one battery lead, leave the car for 3 days, reconnect battery. if car starts, the fault isnt your battery. if battery is flat, its the battery. you could also use the ammeter on your multimeter to measure the current drain with everything switched off. you would be best to disconnect one lead from the battery and use the multimeter in the gap, but you need to either close the bonnet, or simulate a closed bonnet. you could use long leads so you can close the bonnet, but leave the ammeter out of the car. then see what current is being drawn. anything over about 0.05 amps is too much.

[Pimped-Passat]

zollaf...

Great ideas. Thanks for the tips, I'll try the disconnected battery first. As I'm no auto electrician, does it matter which side I disconnect...? + or - ..?

Also, with the battery disconnected, will the car be "OK" once it's reconnected..? Warning lights, things resetting, etc...? You know what I mean.. will it mean a trip to the dealers for a reset using VAGCOM (or whatever its called..!!)

Many thanks
Mark

[mikecb1]

If it's any help, my 56 plate Tdi Sport 170 sometimes goes for 2 weeks without being run, and (so far) I've never had any problem starting it.

Mike

[martin1810]

You can't test a battery with a multimeter but the fact that the voltage dropped so low means it is going flat. You can disconnect and reconnect without effecting the car.

[forge197]

I left mine for just over two weeks and had to get Green Flag out to get it going, shall monitor it and see if the time to flat decreases.

3 days doesn't sound right though.

[johnloaderuk]

If it's any help, my 56 plate Tdi Sport 170 sometimes goes for 2 weeks without being run, and (so far) I've never had any problem starting it.

Mike

Mine too. A couple of times I've left it for two weeks in an airport car park, and it starts first time, just like I left it there the day before. And that's on a now three year old battery.

[Stuart W]

My battery was replaced when the car was less than 3 years old/80,000, which was disappointing, particularly when it was obviously sub-standard for at least a year before that.

I asked VW to look at it when under warranty, but they said it was my taximeter that was running it down, which I wasn't convinced about, but they said the battery was OK, so I took their word for it.

A while later and it was clearly on its last legs. I took it in for a service and asked them to look at it, however they must have left the ignition on while working on it and they couldn't start it!!

Of course, it was out of warranty by then, so unsurprisingly it was the battery at fault!!

Haven't read much in the way of other battery problems on here, so mine was probably just a rogue as Mark's might be.

Fine with a new battery, but my wallet was a ton down :mad: