Volkswagen Polo III (1994 - 1999) - 96 1.4 Charged battery - gone flat overnight

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Mon 18 Aug 2008 19:28
96 1.4 Charged battery - gone flat overnight - shirike
Hello,

A week or so ago I noticed my immobiliser was not blinking as usual and my digital readouts were faded when I got into the car but then went blank after first attempt to start the car. I figured the battery had died (I hadn't used the car for a few days and thought I'd left the lights/radio on or something) so quickly got my powerpack out and jump started the car and thought nothing of it - I took the long route to work to allow the alternator to build up enough charge for starting the car in the evening.

That turned out to be the case and the car started fine after work and drove home. However, the same thing happened the next day so I checked the fluids in the battery and they seemed ok. However, the battery was ancient and I'd had it since I bought the vehicle and I decided I'd buy a new battery.

I installed the new battery and everything was fine for about 6 days and then the same problem occurred - all electronics out on the car in the morning and it would only start with the powerpack connected.

I checked the battery charge level and it was very low (between 1 and 2) so charged it fully through the day - I installed the battery again and tried to start the car. It worked like a charm.

However, overnight the battery has drained somehow and the car will not start.

I'm at a loss - I've not changed any wiring and all the fuses appear to be fine.
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Mon 18 Aug 2008 19:42
96 1.4 Charged battery - gone flat overnight - Screwloose

You need some basic test equipment to check your charging system and to see if you have a drain.

Do you have access to anything like a multimeter - or even a test-lamp?
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Mon 18 Aug 2008 19:57
96 1.4 Charged battery - gone flat overnight - jimbano
Hi,

If you sit in the back of the car with all the doors closed, lower the rear seat and see if the boot light is stuck on.. you have to make sure all doors & boot are shut tight. If the light is stuck on then this would cause the battery to drain overnight as you say. The boot light switch is located in the boot lock mechanism and they are prone to water ingress and corrosion.
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Mon 18 Aug 2008 20:11
96 1.4 Charged battery - gone flat overnight - Screwloose

An even easier check is to open the boot and put your hand on the lamp. If it's been staying on, it'll be red hot.
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Tue 19 Aug 2008 11:57
96 1.4 Charged battery - gone flat overnight - shirike
We've checked all lights - there are no lights left on when all doors are shut etc.
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Tue 19 Aug 2008 13:32
96 1.4 Charged battery - gone flat overnight - Collos25
You need to put a meter in series with the battery with everything switched of take a note of the load then one by one remove the fuses till the meter goes to zero and find what that circuit controls.
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Tue 19 Aug 2008 15:20
96 1.4 Charged battery - gone flat overnight - Peter D
This could be a failed rectifier pack in the alternator. No only can this fault discharge the battery but it does not charge it very well. Disconnect and leave overnight. Reconnect and start, if all is well then that may be your problem Regards Peter
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