Battery drain check

sprintmaker · Feb 27, 2010

Can any electrical wizards tell me how to check how much current is being drawn from my battery when it is switched off.

I have got a meter, just need to know where to test it at.

96 V8i

discool · Feb 27, 2010

Switch your meter to amps and connect the leads in series with the positive battery lead.

biolandy · Feb 27, 2010

As said take off +ve baqttery lead,then connect meter (on DC AMP range) between the +ve of the battery and the lead you have just taken off-the reading should be only mA unless you have something switched on

stchris356 · Feb 27, 2010

Your better off doing it on the negative lead as less chance of shorting the spanner out:doh:
Make sure theres not too much load on when you connect ignition/glow plugs etc or you will blow the internal fuse of the meter which depending on the meter is usually 10A.

With everything turned off and door closed you should nave no more than 50mA (0.05A), if when you first connect you have a drain I usually wait with it connected about 15-20 mins to make sure everything has shut down, if still a drain you have a problem somewhere.

Start suspecting anything that's not standard kit i.e phone or aftermarket stereo, failing that start pulling fuses while getting someone to watch the meter, remembering to make sure the door contact is closed.

sprintmaker · Feb 28, 2010

Thanks guys, I will check this out tomorrow as the disco has a habbit of draining batteries over a couple of months. I have not been using the car for the past few months but have been using a solar charger to keep the battery topped up. Put a new battery in in December and it did not want to start last week.

biolandy · Feb 28, 2010

You are asking a lot from the battery leaving it so long between runs,particularly if the alarm is "on"

biolandy · Feb 28, 2010

Also has the solar panel got a blocking diode fitted to stop discharge in the dark

stchris356 · Feb 28, 2010

biolandy said:
You are asking a lot from the battery leaving it so long between runs,particularly if the alarm is "on"

That is a very good point, bearing in mind the weather over the last three months, if it's been outside for that time and not had a decent run it will go flat.

Is the solar charger connected to your fag lighter if so I'm pretty sure that circuit is dead once the ignition is turned off?????????

sprintmaker · Mar 2, 2010

It's been on a sorn as it failed the MOT due to an ABS fault which I have only got fixed today so I have not been able to drive it. Just wanted to do a check in case there is a drain on top of it not getting used very much.
Don't know if solar charger has a blocking diode fitted but it was connected to the battery directly.

Hope to get it MOTd within the next week or so ready for caravan season as old TDI is a bit slow at towing.

Battery drain check

sprintmaker

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stchris356

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sprintmaker

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biolandy

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