Battery Problem

Hi all,

I have a problem with the battery going dead after a day or two if the cars not driven.  I know this could be a million and one things but is there a common reason for this?  I read something about a bad earth doing this??????

Hi

        I work for the AA the procedure we use is first test battery voltage if below 12.2 volts boost start.

       Then test charging, needs to be 13.2 to 14.8 volts and then we use an inductive ampmeter we look for a current draw by the battery we look for an increase. Run the engine for 5 to 10 mins and test the battery.

        We use a dedicated battery tester but you can do this with a volt meter, with battery voltage below 12.8 volts disable the engine so it wont start, crank the engine for upto 15 seconds the voltage shouldnt drop below 9 volts and shouldnt drop more than 0.3 volts after the initial volt drop. If battery voltages fall outside any perameters then the battery requires replacment.

          If the battery test passes test for a current drain it should be no more than 50 MA all switched off.

          Note if batteries spend to much time in a low state of charge the become sulphated inside. This has an effect on current draw due high resistance inside the battery.

Hope this helps

Good advice ^^^

If it ends up not being your battery, I've had some problems in the past with my 8v cab not charging the battery. I'd forked out for a new one and it was still going flat! It ended up being a really bad connection on the starter motor where the two cables meet from the battery and the alternator, there was a big dividing plate that was really corroded stopping the battery charging sufficiently.

If your battery simply isn't getting enough charge its easily checked like Ianaa said.

This is the time of year that a weak battery will give up the ghost tho, when it starts getting colder.

Hi

One way you can check bad connections is by using the volt drop method. The diagram shows a starter set up but the same method can be applied to the to the alternator circuit. The closer the the volt drop reading is to zero the better.

my old alarm/immobiliser kept draining mine, took a week thou