gordy.r Posted October 21, 2014 Share Posted October 21, 2014 Ok so it has happened twice now over the last few months. Car runs fine and all seems well, but on two occasions I've gone out now and the after market alarm key fob won't unlock the doors and when I get in using the key the car battery is dead. Once charged all seems fine again until the next time. No lights left on etc so no idea why this is happening unless my battery is on the way out, but the last test done by the AA said the battery was fine. Any suggestions? Quote Link to comment Share on other sites More sharing options...
supra joe Posted October 21, 2014 Share Posted October 21, 2014 Alternator. Mines just done the same... Quote Link to comment Share on other sites More sharing options...
Marcus GTE Posted October 21, 2014 Share Posted October 21, 2014 Take your car to halfords and they do a free diagnostic in the car park. They might try and sell you a battery but should be able to tell if your alternator is goosed. Quote Link to comment Share on other sites More sharing options...
gordy.r Posted October 21, 2014 Author Share Posted October 21, 2014 I'd be surprised if it was the alternator as it was replaced around a year / 5k miles ago, might run it down to Halfrauds anyways and have it checked. Was wondering if it could be the distiller water levels in the battery? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 21, 2014 Share Posted October 21, 2014 Most batteries are now sealed, you might have to perform surgery to top up the electrolyte level, if it's possible at all. Just load up the battery / alternator with everything you can think of electrical in the car turned on, rev to 1500 RPM and put a multi meter across the battery terminals. you need to see about 13.8 volts DC . Much less and the alternator is suspect. You need a discharge meter across the battery to see what its stand alone condition is like, they are quite dear, take advantage of Halfords or similar for that. Quote Link to comment Share on other sites More sharing options...
gordy.r Posted October 21, 2014 Author Share Posted October 21, 2014 Most batteries are now sealed, you might have to perform surgery to top up the electrolyte level, if it's possible at all. Just load up the battery / alternator with everything you can think of electrical in the car turned on, rev to 1500 RPM and put a multi meter across the battery terminals. you need to see about 13.8 volts DC . Much less and the alternator is suspect. You need a discharge meter across the battery to see what its stand alone condition is like, they are quite dear, take advantage of Halfords or similar for that. Cheers again for the advice, I'll give that a bash. (Email inbound tomorrow as well reference our telephone conversation earlier) Quote Link to comment Share on other sites More sharing options...
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