Nissan Sunny 1988 1.6GSX - Keeps going Flat

[pacuk01]

Hi,

My mother has got an aging Nissan Sunny. Been a very good car. But over last couple of years it has had a problem where battery seems to go flat in cold weather, and the car wont start. Replacing the battery has usually seemed to cure this until this year.

I have put on a new battery. Car goes flat after 4 days if damp and cold. I replace this new battery as it might have been faulty. Still have same problem. I test the drain on battery when car is engine and ignition is of and decided that the small drain on the battery might be caused by a faulty alternator. I fit a new alternator, the small drain on the battery now goes away, but after four days of non use the car still goes flat. I am running out of ideas. I understand there might be an intermittent power drain on the battery which is enough to make the car fail to start. How will I find the fault. or will it just be easier to fit an isolator to the battery to stop the drain.

I am at the end of my tether on this one, and so is my mother.


Any help please?