Electrical Leak?

[def9087]

My defender td5 continually gets a flat battery after about a week of not driving it.
i have had it off the road for a week now doing some other work and now its beyond starting. i have taken the battery back to the manufacturers who assure me the battery is fine- charging and holding its charge and has been load tested.
i have been told it is likely to be a earth leak? my secondary battery seems fine and so the isolator is working. but i'm unsure how to find out where the starting battery is leaking to/from.
can anyone suggest how and where to start on this?

[Judo]

First thing to check would be to make sure your alternator is charging the battery properly. Can you start the vehicle and check the voltage? Should be over 13v, maybe close to 14v.

[Judo]

If the alternator is working, try some of the suggestions in here:

http://www.aulro.com/afvb/technical-chatter/178174-mystery-current-leakage.html

Basically, you can put a multi meter between positive battery terminal and battery on 10A setting first. That will tell you if there is something draining the battery. If there is, you can then start checking at the fuses to narrow down the search.

Another way - if the current draw at the +ve battery terminal is less than 1A, you should be fine to leave the meter connected, then just try pulling fuses out 1 by 1 until you see the reading drop.

Multi meter is the key...

[nedflanders]

Remember all cars have some leakage and after turning off the ignition it can take a few minutes for everything to shut down. As has been said put a multimeter in line with the + and start pulling fuses, then relays to find out what your problem circuit is. Expect to see 0.1 amp or less if everything is OK.

[def9087]

HI thanks yeah i have an EMS2 which tells me the alternator output with is about 14v.
do most multimeters have an amp setting?

[Mick_Marsh]

do most multimeters have an amp setting?
I've never seen one without it.

[Yorkshire_Jon]

Do your auxiliary circuits use the chassis / bodywork to get to earth or do you have a seperate earth circuit for your second battery?

If its the latter I'd put money on you having an earth leakage problem as has been hinted at.

Fail in that, have you got a faulty device somewhere?

R
J

Sent using Forum Runner

[def9087]

the secondary battery has its own earth leads. but the main battery runs through the chassis.
what does an earth leakage mean?
when i charge the battery up will look at the leak by removing fuses hopefully its in something simple

[def9087]

thanks Ned(?) ,
I have put the multimeter in line and pulled fuses.
it started out with all fuses at 0.16 , then dropped to 0.08 when i pulled out the reading light fuse ( stereo flashed at the point so maybe its wired to that fuse)
is 0.16amp something to worry about? what is a normal amp output on a defender when everything is switched off?
thanks

[Judo]

I don't know for sure, but a few clicks on the calculator and it seems too high. Your battery would be drained enough to not start in 1-2 weeks according to my VERY rough calculations. Since that roughly matches your original post, I'm saying 0.16A is too high.

[nedflanders]

I'd be looking at anything over 0.1 being too high for something as relatively simple as a Defender. When I was checking for drain at breakdowns normal readings for something like a RRS would be in the region of 0.08 and say something like a Ford Focus would be around the 0.03 mark but all cars varied.

[Dorian]

Just did my MY12 Defender and it was pulling 0.16A. Flew to Tamworth early Monday morning and came back yesterday night so it sat at the airport for 4 days and no problems starting. Didn't take note of the voltage when I started but the Ultragauge normally sits at about 14.25 -14.40 volts. Hope that gives you some reference numbers.

[nedflanders]

Volts are largely irrelevant, a battery showing 12.5v can still be knackered if its got no amps, 4 days on a new battery isn't really a good indication, mine will start after 2 weeks no problem on its original battery (04 TD5)

[Fraz]

An ultra guage type tool will report the voltage while the engine is running, therefore the 14 odd volts the alt pumps out. Not a good indication of battery volts, and as stated, cranking capacity

[def9087]

I have narrowed it down thanks NedFlanders,
using the technique suggested. Amp meter in line with all fuses was drawing 0.15, then when i removed the interior light fuse it dropped to 0.07.
then i was stumped so started at the starter motor ( is that the first point the battery goes to? ) so then went right back to the battery with extra leads attached to the starter battery. i have a jumper lead hardwired in to an Anderson plug in the back seat for easy jump starting and this lead was drawing 0.04/5 . it has a light that says if the battery is charged and connected etc but i didn't think it would draw so much.
and now have it down to 0.02 if both those points are unplugged, but i'm unsure how to get them sorted . any tips?
thanks Jake

[bee utey]

Get a better quality radio that doesn't drag the battery down, or turn it off altogether.

[nedflanders]

If you removed the interior light fuse it dropped to 0.07 that's acceptable, a decent battery should last on that. Does the interior light switch fuse power anything else?? Some fuses power a number of circuits without you knowing? If it doesn't them look at door switches etc, some alarms also look for volt drop when a door is opened and the light comes on. First checks we used to do was glovebox light and boot light.

[Dorian]

i have a jumper lead hardwired in to an Anderson plug in the back seat for easy jump starting and this lead was drawing 0.04/5 . it has a light that says if the battery is charged and connected etc but i didn't think it would draw so much.
and now have it down to 0.02 if both those points are unplugged, but i'm unsure how to get them sorted . any tips?

Jake,
Have a similiar anderson plug, I have a small house battery for everyday and plug a larger battery into the system when I go away. With mine the LED was in a housing that held the standard Anderson, I could pull the plug apart and cut the LED out. There should be a resistor inline with the LED, take that out as well and tape up the active bare end. Typically the LED will draw about 45 milliamps (0.045A).