Flat Battery.

[bigboack]

Hi all,
Please help, Bought a new battery for £100.00 the other week as was told the other wasnt big enough for my engine,Ok Went away for the week all ok, parked up for a week when got back home,Came to start today flat as a pancake, Now took it to a garage they told me all was fine no loose belts etc,The garage said maybe it wasnt fully charged when i bought it, Nothing was left switched on and im at at a loss as to what it could be, Anyone any ideas as to what it could be.

 

[Nosha]

For a battery to be flat after only a week... you have a drain on it (plus the last battery!) You need to dis-connect the earth or pos' lead and put a multi-meter in the line set on milliamps, if you open the door you will see the reading shoot up as the interiour light comes on.

With everything switched off there should be a VERY small reading, this will be clock and radio memory and ECU. When I bought my Frontera I had exactly the same thing! If theres a reading of more than 200milliamps or there abouts start pulling out fuses one at a time until the reading drops - that's the circuit with the drain! I found whoever had fitted the fancy aftermarket radio had wired the main feed to the battery rather than via ignition so the 10disc CD changer was ALWAYS live, once I had the memory wire to live and the main feed via ignition the battery never went flat again!

If you find there's no drain, then it has to be a dodgy alternator that's either not giving full charge or is taking a feedback thro' a faulty diode pack.

(If you don't have a multimeter you can use a 5w 12v bulb which will glow brighter the more you pull through it, i.e it should be very dim with all doors closed etc). Hope that's of help.

 

[bigboack]

Nosha, thanks.

Thanks for the speedy reply, Will try this out tomorrow and let you know how its gone.