Hi,

I've got a Y Reg Polo which suffers from a flat battery even if I don't drive the car for 2 days. I've changed the battery and the alternator as I previously had an issue the alternator but I'm still having the same problem. I've already checked that no electrics are left turned on when I lock the car.
Has anyone got any suggestions as I can't seem to find the root cause of this?

Edited 13 October, 201312 yr by yasir152

Do you have any aftermarket ICE fitted, like an amp?

No I don't just standard kit

If you have a multi-meter, set it to the highest AMPS position, disconnect a battery cable and connect the meter between the battery terminal post and the removed lead (in series).

Anything above a couple of hundred milliamps could mean that something that shouldn't be, is in fact drawing current. (common items for doing this are interior lights, boot lights and glove box lights, but a faulty alternator rectifier (diode pack) will also do this.

If you don't have a multi-meter, you could try simply leaving the battery disconnected for a couple of days when you aren't using the car, if it still goes flat, then you have a faulty battery which you should be able to get changed by the people who supplied it.

Regards.

I also have this problem!!!!

2001 Polo 6n2 1.4 TDI

Replaced Battery & Alternator last week, still having dead battery symptoms every few days.

I've bought a voltmeter for the cigarette lighter and the alternator seems to be charging fine, so something must be discharging it overnight.

I've got 2 amplifiers in the car but even after disconnecting these i'm still having issues.

Sorry to hijack but it's a relief to find someone with the same problem as me, please keep this thread updated if you figure it out!!

had this on a seat turn out the radio would turn on when the car was left common on seat also check light in boot as I no this happen to someone and it was that but when they closed the boot they could not see it ok hope this helps

Hi,

I've got a Y Reg Polo which suffers from a flat battery even if I don't drive the car for 2 days. I've changed the battery and the alternator as I previously had an issue the alternator but I'm still having the same problem. I've already checked that no electrics are left turned on when I lock the car.

Has anyone got any suggestions as I can't seem to find the root cause of this?

You need to do a parasitic draw test ..Have a look......http://www.youtube.com/watch?v=KF1gijj03_0

Good find on the parasitic draw test, will add this to my 'to do' list :)

The stereo is wired fine, turns off with the ignition and its an aftermarket one so i've done it all myself. Just checked the boot light yesterday and it goes off fine, so that rules something else out.

There's definitely nothing turned on at all when I leave the car, my only other suspicions are:

High draw from stereo (permanent live for memory)

Faulty alternator that charges but causes current draw when not running.

Also, for some strange reason my alternator only starts charging once the car has been revved above 3000rpm. If you start the car and drive away keeping the revs low (trying to be economical), the battery continuosly reads 11.8-12.8 volts. you can drive a good 5 miles or so carefully and the alternator still doesn't kick in. Blip the throttle once to 3000rpm and it starts charging at over 14 volts, and is then continuous for the rest of the drive, no matter how low the engine rpm is.

I recently replaced my alternator with this one from a salvage yard but it's under guarantee. Is this a common occurrence on the 6n2?

I've got a voltmeter off the cigarette lighter at all times to monitor its behaviour.

TO PETERABBOTT33.

Your problem sounds very much as if it is down to the alternator.

As it still charges OK after you 'boot' it, it could be that the brushes and/or slip rings are worn or contaminated, however, it could also be down to a faulty diode in the rectifier.

Another possibility, but less likely, is that the warning light (battery light) or its connections are not working as they should - If you disconnect the wire from the SMALL terminal at the alternator, earth the wire and switch on the ignition, the warning light should light up (DO NOT try this with the LARGE alternator terminal, or you could start a fire!!!) - alternators need the current from the warning light to initiate the charging.

As your 'new' alternator is under guarantee, I would tend NOT to do anything with it, but you could strip the old one and check it over - Look to see if the brushes seem to be contacting the slip rings, if you have a multimeter, use either the diode test (if it has one) or set it to Ohms, disconnect the rectifier from the stator windings and check that current will only flow ONE way through the diodes - if it flows in both directions, you need a new rectifier pack. You can also check the condition of the rotor windings with the Ohmmeter, if things are as they should be, you will have ABOUT 6 Ohms resistance through the rotor (place one test prod on one slip ring and the other test prod on the other slip ring to test the rotor)

It's more difficult to check the stator windings, but if it has been overheating, you may be able to see burnt varnish and/or smell it. However, is it does in fact charge, it is unlikely that the stator windings are at fault.

Regards.

I think I've found the root cause of the battery issues. If I change the boot lock from central locking mode to manual then the battery won't get flat after a few days of being idle. Looks like some electrics issue with the central locking which is causing the boot to still generate power from the battery. I'll monitor it for a week or so and if this is the issue then I will just have to leave the boot on manual lock mode.

I thought the problem was solved by changing the boot to manual lock but it hasnt. I still get a flat battery even though I drive it the previous day. I've got a new battery and alternator so I'm not sure whats causing this. I cant see anything else thats left switched on which could be flattening the battery

Did you ever find out why it was being drained?