How do i check why my battery in my car keeps going flat after 36 hours.?
Car batteries can be fickle … assuming the alternator is charging okay and there are no drains on the battery when the car is locked up, I would think the battery has poor cell structure. This happened to me last year with a three year old battery that the dealer tested and tested, gave it a pass, but it still kept going flat. I insisted that they change it and guess what, no further trouble for the next year. Often a battery test ( voltage and testing durability with a heavy load tester ) is not fail safe. So check the charge, check for anything that may be draining … if these come up okay, get a new battery, especially if its a few years old. Modern batteries are much, much better than say 30 years ago but occasionally they still give up! Oh, on more thing, just make sure all connections are tight and clean!
