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1997 D1 v8. battery discharging in 8 hrs

alex park

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not anymore really, used to tow my boat around but sold that.

it's twin electrics one.

ive found the power for it which was spliced into the battery via a terminal and then through a relay.

i have noticed that one of the wires that comes from the realy goes to the back of the alternator.

Just wondering if this is for the warning lights for the trailer, a similar sort of thing as the alternator warning light?


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ah yes that would make perfect sense, charges as the car battery is charged.

gonna pul the elctrics out from under the car, i can see the loom has got quite close to some of the mounts, so it could be it has been pinched against something and shorting.

we'll soon see.

thanks for all your help so far.


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ok the very first fuse i put back in was the trailer lights fuse (fuse 6 satallite 2)

this made the terminal spark.

i removed this and replaced the others one by one checking each one to see if it also made the terminal spark.

the rest never.

so the trailer lights fuse was the only one to do this.

i have removed this.

what is the significance of this "sparking" caused it seems by the trailer lights wiring?

excuse my ignorance, like i say mechanically i dont mind fiddling around but the electrics bit scares the pants off me.

also earlier GUY H asked if i had trailer lights fitted, was this because its a common fault?


The spark method is a slightly crude way of seeing whether a circuit is drawing current. Think about shorting the battery (DON'T TRY IT) the 'spark' is big enough to make tools go bang and start fires, when a circuit is drawing less current then the spark will be smaller and smaller.

You can get a spark with modern electrics (ECUs etc) when you connect the power as they have nice capacitors inside them which drawn a relatively large current for an instant and then nothing at all once they are charged up.

Glad you seem to have found the fault.

Possible normal causes of current drawn by a trailer socket

1. bad wiring routing causing chafing and 'shorting'

2. bad sealing of socket causing all sorts of cr@p to end up inside causing a 'short'

3. you've left your caravan hitched up all this time ;)

and it's most likely the grey socket as that has the permanent live feed in

let us know when it starts in the morning :)

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flat again this morning.........

ok ok calm down breaaaaaathe....

battery is brand new.

so i know it's not the battery, when i leave the leads off it hold it's full charge no problem.

i left the only fuse out which was causing a spark at the termninals which was the trailer lights, i have also disconnected it from the battery and from the charge lead to the alternator.

on the alternator, there are three wires.

the large main wire to the battery which is at the top of the alternator (as you look at it in position in the engine)

the centre wire is brown and is a thin one. this was the wire that the twin electrics from the trailer lights was spliced into ( i believe to charge up a caravan battery etc whilst on the move)

the third and lowest is a white wire on a blade connection.

when i took the top large wire off and ran the engine, it showed the battery light and did not re-charge the battery, so i guessed this was the charge wire.

is this correct...

oh what a mare this has become....

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the battery had gone from 12.8v at around 5pm last night to 11.4v at 7.30am.

so at least i know that the trailer lights were part of the problem as the battery would have been totally flat if i hadnt remooved the offending fuse.

there must just be more leccy stuff out of sinc.

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Ok, so go back to plan B and pull fuses tonight.

Shame your are so far away remote diagnosing electrical faults is not easy, sometimes you miss the obvious by not actually seeing it.

The other thing you can do is, once you have pulled out half the fuses tonight is to stick your meter (on the 10A scale) and putting the red lead to the live terminal and the black lead to the load bridge the fuses and find which ones are drawing current.

Actually tonight, it might be best to pull all the permanent live fuses just to make sure we are on the right track

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left the charge wire off the alternator overnight and it seems that the battery went flat anyway.

Just going through the old posts

Which lead did you leave off, the small one (prob with the trailer 'split charge' feed on as well) or the big one?

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i know its difficut diagnosing from a distance.

i should just liketo say a big thanks to all those that are helping me.

its a good job i've been off work for 8 weeks with a broken pelvis, so only just on the mend really, so scrabbling about aint to easy.

but i'm gonna full the live fuses as you suggest and see where we end up from there.

thanks again, i had high hopes last night but, at least i'm learning all the time (mainly to steer away from electrics and stick with mechanicals stuff)

thanks again

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The thin brown wire probably went to a split charge relay. This is a sensor wire so that it doesn't provide power to the caravan battery when the engine is not running. What happens is that the alternator supplies 12v from this terminal. When the alternator is running this then goes to earth and so makes the circuit. A faulty split charge relay would mean it's trying to supply power all the time.


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Unlucky! That's annoying - well it sounds like it half solved it.

So you've removed the battery altogether and it stays charged fine.

You've connected everything up and the battery fully discharges within a few hours

You've connected everything up except the towbar circuit and it slightly discharges overnight

Is there anything else connected up with the tow bar electrics, sometimes they have another feed going to the battery and the feed that you have disconnected just goes to a relay to activate the main feed, if you haven't already disconnect the main feed as well, as said above disconnect any aux lights like spots or anything else,

Then do the ammeter check to between the positive terminal of the battery and the positive lead and see what it's coming up with now

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ok the only other thing that was connected to the battery was the LPG power source which was connected to a electronic feedback box.

i have totally removed all the other wires other than the main positive and neg leads.

putting the mm across is still showing the figure 1 ???

i have just removed all the fuses from satallite 2 and give it a couple hours see what that does.


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I had something similar , turned out to be the altenator bearings shot so that the stator would slide forwards and backwards so far that the brushes sort of shortend on the sliders .

Did'nt make noise however.

Good luck

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i think i may have found something.

when i had the trailer lights fuse out (which we thought was the problem) this is obviously on the same circuit as the interior light, the heater and the clock as they no longer worked.

however when i was checking the amps on the interior light(which showed 0.35 or 4-5w) with the help of some advice from Guy H.

i noticed that the clock would keep flickering on especially when i turned the interior light switch to the on position...

do you think this could be part of the problem.?

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Normally I would say that would be a problem but I noticed a very similar thing with my car - when I was changing radios I managed to blow a fuse, and what confused me was that although the fuse was blown the lights on the radio kept flickering, if I played about with the interior light switch it stopped it in one position and made it flicker in another.

So I don't think it's a problem - I don't have any problem with it discharging anyway!

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well with all the engine box fuses removed, the battery has remained charged.


i think i will put them all back save for the alternator one and the ignition circuits one and see where we go from there.

does the 100amp alternator fuse just control that particular circuit or others also and..

same with the ignition circuits fuse, are there other circuits that this controls?


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