My Mark 3 (NC 2006) has very recently caused me problems. The car is garaged and wet journeys are avoided! It invariably starts first time and I regularly use a Maypole MP7423 electronic charger to keep the battery topped up. The battery is twelve months old but when I attempted to start the car last week the battery was completely flat and lifeless. I have obtained a replacement under warranty but putting a multimeter in series with the main battery lead reveals there is a leakage current of over 1amp running all the time. Has anyone had a similar experience? Any guidance to resolve the problem much appreciated.
Just check you haven’t left the interior light on and the boot light goes out when the lid is closed, switch that off anyway if laid up.
Apart from that there’s not much more that can stay on to cause draw on the system for the battery to flatten.
Hi I have a similar car and keep it under similar conditions but have a charger that goes into maintenance mode so can be left on permanently. (I have a Clarke one but also heard CTEK are good)
If I leave it off for 5 or 6 weeks (forget to plug it back in) it goes completely flat and last year killed the battery so I am a bit more careful now.
It seems 4 or 5 weeks is about the limit without it being on charge.
1A is very high.
Usual way to fault trace a current drain is to remove the fuses, one at a time, and to place the multimeter across the connectors for the fuse. That should show you which circuit is responsible for the leak, and you can take it from there.
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Have a look at this
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There is a really good channel on Youtube that I watch. He does diagnostic videos and tells you exactly what hes thinking etc. Seems to really know his stuff. You don’t need all the flashy kit he has, just a multimeter
Many thanks for your various comments and suggestions. The You Tube videos are very helpful and certainly point the way forward. At the moment the car seems to be behaving, so the fault appears intermittent with no leakage current (US = parasitic draw!). At least I can approach the problem logically if it recurs. Thank you all for your help.
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I once had a Vauxhaul Astra that had similar problem and symptoms, however the parasitic current drain was slightly higher than 1A ( possibly 2-3 A ! ).
One cold frosty morning i noticed that the frost had melted on the bonnet ( Hood ) in a particular area, directly under this area was the alternator which was very warm to the touch.
My alternator had developed an internal fault which caused a short circuit, generating heat.
Not something the average person has in their home toolbox ( including me ), however If you did have access to an infra red camera, you could point it at the car and see if there is a heat signature anywhere. We have one of these at work to help pinpoint potential leaks when trouble shooting air conditioning system faults on our Aircraft, expensive bit of kit, however I am sure there is something that connects to a smart phone these days, they seem to do eveything else…