flat battery again

[cantab27]

just jumped in the pos first time in a week and battery's dead ... battery's about 4 weeks old ..no lights left on.... used to do this with old battery if left for a few days or more that's why i brought a new one :boohoo:
is there a common thing that can drain power from battery while sitting for more than a couple of days... any thoughts
cheers :thumbsup:

[BlueXJ]

Check all your grounds especially the main one from the head to the firewall. Next order of business is to check the ground on the alternator.

[4.3LXJ]

Sometimes the alternator can drain a battery. Bad fields I think. The catch is that it will still work.

[Mudderoy]

I believe this is safe, double check it before trying. Remove the ground from your battery. With everything off on your Jeep put your DVM (Digital Volt Meter) set up to read AMPs in line between the ground and the negative terminal on the battery. I seem to remember a max of 40ma is acceptable draw on a battery. If it is higher than that then you need to find the device, or the circuit that is causing the high current drain.

We I say safe, I mean to the DVM. Most DVMs only measure very low current.

[rguignard]

if you have a alt shop near you pull it off and send it to them i bet thats whats giving you the problem. or it could be the big boom box in the rear :smiley-laughing021::thumbsup:

[cantab27]

cheers guys , if it ever stops raining here i will check these things ....

[Thomass]

Great, and a good day (it is really early in the morning for you)
assuming that you did not weld on your vehicle with the battery connected the following....

did you, measure the battery voltage with nothing on (contact off)
readout ?? does it drop ? if so, or the battery is broken, or some of the electric wiring what transport current/voltage before contact is switched on has a short. (possible rust)

contact on, does the voltage drops ? how much ?
after starting the engine, does the voltage raise ? how much ?

a battery with 6 cells if empty voltage should be 12 volts (2 volt per cell) if lower the battery is or in bad shape or on of the cells are broken (sulfate)
if the voltage does not raise after starting the engine, (suppose to go to 13/14 volts) probably the brushes are bad and need to be replaced. if the voltage goes way beyond the 14,5 volts you should check the regulator (inside the alternator)
in the FMS, you can find how to replace those parts.

I will hope this will bring you to an solution

Thomass