Parasitic Drain (Not child related)

Fingle · Nov 2, 2018

Hi
Im my never ending quest to have an easily starting 300tdi in the coming colder months, I have discovered a 1.5 amp drain on the battery when its parked. This may well go some way to explaining why its so pathetic at starting after a week etc.
I have done some nosing on the forums etc, and it seems likley (although I need a mate to keep and eye on the multimeter while I pull fuses) that it could be a dodgy alternator.

So a couple of questions spring to mind while I wait.
1. what do the little spindly wires out the back of the alternator do? Another forum said he fixed the drain by pulling these out.

2, What other things are likely to draw 1.5 amps while the ignition is off (central locking)?

3. Would 1.5 amps drain make a massive difference to a fully charged 1000CCA batter over a week?

Discokids · Nov 2, 2018

Fingle said:
Hi
Im my never ending quest to have an easily starting 300tdi in the coming colder months, I have discovered a 1.5 amp drain on the battery when its parked. This may well go some way to explaining why its so pathetic at starting after a week etc.
I have done some nosing on the forums etc, and it seems likley (although I need a mate to keep and eye on the multimeter while I pull fuses) that it could be a dodgy alternator.

So a couple of questions spring to mind while I wait.
1. what do the little spindly wires out the back of the alternator do? Another forum said he fixed the drain by pulling these out.

2, What other things are likely to draw 1.5 amps while the ignition is off (central locking)?

3. Would 1.5 amps drain make a massive difference to a fully charged 1000CCA batter over a week?

1. Don't do that. Post pics of your alternator for further advice.
2. 1.5A is roughly the draw of two tail light bulbs (I think)
3. CCA is what thebattery can deliver in one big hit so not relevant, we need to know the ah rating.

Fingle · Nov 2, 2018

90AH.
too dark for photo, will try tomorrow

EeEk · Nov 2, 2018

1.5 Ais quite a drain. A modern day ford car would be less than 0.3A thats enought for keep alive stuff like clock/radio/alarm.

The little wires....one is the warning light. The other is rev counter. I doubt its either of them.

I'd connect an Amp meter and pull fuses and relays and see what you find.

SteveSw · Nov 3, 2018

Had a peugeot with a similar problem - it was indeed the alternator and was caused by a build up of carbon dust on the rectifier. Dismantling and a good clean sorted it

1988smithy · Nov 3, 2018

I would like to let the OP know that I like the title of the thread. As there isn't a button. For liking thread titles.

leeds · Nov 3, 2018

A constant drain of 1.5 amps per hour is 36 amphrs/day from a 90 amphr battery.

That battery will be fully discharged in less then 3 days. A battery will start to struggle when the battery is less then 50% charged.

If you can not isolate the large parasitic draw an isolator switch with a bypass fuse for radio and alarm might be way forward.

Brendan

urena · Nov 3, 2018

best of luck finding it.
nightmere of a job.

brian47 · Nov 3, 2018

Generally there are only a few circuits left live when the vehicle is locked, for instance, radio, clock, central locking, immobiliser and of course the alternator.
One problem with trying to trace a parasitic drain is often when a circuit is disturbed the alarm circuits might need 1/2 an hour or so to go to "sleep" again.
If I were trying to track this down, the first place I'd check would be the alternator. By all means disconnect it and recheck the drain but do not run the engine with it disconnected.
If you have a multimeter and you're fairly adept at using it, there is a way to estimate the current being drawn through each fuse without pulling them.
Let me know and I'll post the relevant pages for you.

Fingle · Nov 3, 2018

If it does turn out to be something mysterious. Il just fit an isolator switch. Would like to have it in the cab, would mean quite a bit of fettling

I dont have an imobiliser, or a radio. Meant to have central locking but I need to get round to those springs :/

8ha · Nov 4, 2018

I think an isolater switch is a good idea I used car ones but they did not last long so igot aheavy commercial one 10 years no trubel

brianp38dse · Nov 5, 2018

These are quite good at helping to trace power drains
https://www.ebay.co.uk/itm/Neilsen-...h=item2a82df758e:g:3hYAAOSwYvFZIBm7:rk:2:pf:0

Parasitic Drain (Not child related)

Fingle

Active Member

Discokids

Well-Known Member

Fingle

Active Member

EeEk

Well-Known Member

SteveSw

Member

1988smithy

Well-Known Member

leeds

Well-Known Member

urena

Well-Known Member

brian47

Well-Known Member

Fingle

Active Member

8ha

Active Member

brianp38dse

Well-Known Member

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