Stuart, Hi,
IMHO trying to gauge battery health with a DVM (probably not a hugely expensive one ie less than a couple of hundred quid) is very diffcult, DVMs have very hi internal resistance and unless a cell has pretty much shorted out you will see around 12/13 v depending on meter, even on a pretty flat battery, its the ability to deliver/accept current that causes problems, a good battery place will have an instrument for checking battery condition, ON NO ACCOUNT TRY TO MEASURE CURRENT ACCROSS THE BATTERY WITH A DVM IT WILL AT BEST DESTROY YOUR METER,
in previous posts you have said that the problem exhibits with battery off car, then you said later that the problem had gone if you disconnected the battery, first you need to decide if this is the case, so are you sure that with the battery off the car the chargers work ok, if so then you are almost definately looking for a current drain with ignition turned off, if this is the case you will need to do some logical fault finding, one way would be to follow procedure in my previous post. If you do not feel happy doing this a good electrician/auto electrition should be able to identify if there is any current drain within about 5 minutes and a couple of hours to find which circuit, fix may take a little longer
Just a thought, when you disconnected/connected battery earth did you notice any sparking as you disconnected/connected the lead.
If you want to dive straight in to look for a current drain,
with battery on car +v terminal connected, turn OFF ignition disconnect earth at battery, set DVM to measure DC current, set to measure 2amps or more, connect DVM leads so red lead is on negative terminal of battery and black lead is on earth lead so you are putting dvm in series with battery circuit. if v low reading reduce range until you get a reading, if you get one let us know wha it is
keep at it and I am sure BC can help find the root of the problem
Edited by - tbird on 27 Aug 2009 10:18:33
Edited by - tbird on 27 Aug 2009 11:36:23