Friday, November 21, 2008 - 06:32 pm, by: David Henderson(Hendo)
I agree with David Vaughan's method. Try and isolate where the drain on the battery is coming from, you can also use a current clamp meter which makes things even easier.
Also, it could be that your alternator is not charging properly, check these values against your car (measure across battery terminals)
ignition off- 12- 13.8v Car idling battery voltage- 14.4v lower than 10v- collapsed cell. totaly F*$ked
If it is lower when idling, chances are its an alternator problem. The remedy may be as simple as bad connections in the fuse box, battery terminals (remove, clean with sandpaper and re tighten) or the main earth from the engine and battery to the chassis.
I have worked on taxis lots and there's so many things that can go wrong. some rarer problems can be terminals shorting on the bonnet, or the alternator diode blowing and OVER charging the battery... say at 15+V, which will kill a battery really fast.
