Battery going flat every day

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trade4us2, Apr 3, 5:30pm
It's not my car!
Battery is new.
Alternator is charging battery OK.
Something is draining the battery at 4 amps.
How to find out what it is?
I have a simple suggestion, but is there a proper way to find out?

gph1961, Apr 3, 5:36pm
vxa=w
say
12x4=48
more likely12x0.4=3
what say you pilgrim?

gsimpson, Apr 3, 5:39pm
Try pulling fuses out until the current draw stops. Then you will have it narrowed down a bit.

tony9, Apr 3, 5:44pm
Charging system is faulty, traction battery is feeding back into the grid at night instead of charging.

trade4us2, Apr 3, 5:49pm
Brilliant! That's what I said he should do. But he's been taking it to auto electricians who seem to be clueless.

chito, Apr 3, 5:52pm
Do you disable the flux capacitor at night?

intrade, Apr 3, 5:55pm
you hook up a amp meter and start pulling fuses till you found the fuse who feeds the draw. then you go on the hunt what and where its being used up.
ah i see somone else already posted a howto lol

gph1961, Apr 3, 6:05pm
a 48 watt draw is huge like almost 1 headlight on low beam
is anyone in there McFly?

andrew1954, Apr 3, 6:32pm
A trainee auto sparky on his second day of work should be able, armed with an ampmeter, be able to track down the circuit that is causing the current draw. it is auto electric 101 !

cabrio1, Apr 3, 6:37pm
Make and model?

trade4us2, Apr 3, 7:03pm
I have never found an auto electrician who has solved anything. I have ended up fixing things myself.

It's not my car.
2000 Jaguar S-TYPE

gph1961, Apr 3, 7:13pm
well that's the end of my contribution then

rbd, Apr 3, 7:25pm
There is the problem, Lucas, Prince of Darkness.

Amazing any year 2000 Jags are still running.

supernova2, Apr 3, 7:37pm
If its a simple short circuit drawing that sort of current then I would think the thing would have caught fire by now. For that sort of load it may not even be a fused circuit but that's the 1st thing - pull the fuses 1 by 1.

intrade, Apr 3, 7:43pm
only thing not fused is the starter motor. if you pulled all fuses make sure to reinsert the fuse pulled or it be a nightmare to put the correct fuses back.
a faulty starter can easy draw 4 amps i would get my flir one out for hunting 4 amps

gpg58, Apr 3, 7:44pm
Boot light/s or an under bonnet light staying on?

unlikely at 4 amps but glove box light maybe.

gph1961, Apr 3, 8:20pm
agreed
see my earlier post

gph1961, Apr 3, 8:21pm
more likely 0,4amp

trade4us2, Apr 3, 8:41pm
The fully charged battery goes flat in a few hours, so the owner has bought a switch so the battery can be disconnected whenever he turns the engine off. That is inadvisable. There's a 4 amp drain if an ammeter is connected across the switch.
There could be more than one device causing the drain.
My guess is that the body computer is leaving some devices on.
In a Jag there are lots of devices that stay on after the ignition is turned off.

gsimpson, Apr 4, 7:17am
Likely to be Bosch which is worse

nice_lady, Apr 4, 7:25am
Computer ? In a 2000 Jag ? Or did you mean the owner as the computer ?

ianab, Apr 4, 7:42am
Electronic Fuel Injection = a computer.

clark20, Apr 4, 7:43am
Most Auto Electricians are very proficient , what area are you in?

tgray, Apr 4, 8:17am
Let us know the outcome.

trade4us2, Apr 4, 8:17am
There is an engine management computer to run the engine and a body computer to run most electrical devices such as lights, wipers, indicators. e.g. the computer fades out the interior lights after the doors are shut, and parks the wiper (there's only one!) properly when it's turned off.
There are separate computers to run the seats!