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4.5 amp draw

Posted: 21 Aug 2019, 08:37
by Teeaitch
I’m flummoxed.

I’ve just acquired a 1984 T3 in camper mode.

I’ve been through the fuse box, the relays, disconnected all the extra bits that previous owners have added to battery leads, disconnected alternator and starter motor, unlinked the leisure battery and I’ve STILL got a 4.5a draw.

My question is, what devices might result in a drain of that size?

Re: 4.5 amp draw

Posted: 21 Aug 2019, 09:57
by shepster
Fridge can be high,

If you have a split charge system in place check how/if It's connected to your starter battery at all.

My fridge relay failed recently so instead of only switching when the engine was running it drained the starter battery instead.

Make sure this isn't the case for you.

Re: 4.5 amp draw

Posted: 21 Aug 2019, 11:17
by Teeaitch
Thanks Shepster.

Like I say, I think I've disconnected all the auxiliaries - I'll go back and have another look.

Cheers.

Re: 4.5 amp draw

Posted: 21 Aug 2019, 11:38
by itchyfeet
Draw from which battery? Leisure or starter batter?
There are unfused electrics on the Starter battery

Re: 4.5 amp draw

Posted: 21 Aug 2019, 12:18
by Cobra88
Manifold heater ?

Re: 4.5 amp draw

Posted: 21 Aug 2019, 16:54
by Mocki
You don’t tell us what engine, nor where you are measuring the "draw" ?

Disconnect the neg from the battery in question and measure the "draw" between the neg pole of the battery and the neg connection you just removed ?

Re: 4.5 amp draw

Posted: 28 Aug 2019, 14:58
by Teeaitch
Yes, I’m taking the measurement at the neg pole of the battery. It’s a 1.9 water cooled petrol.

Re: 4.5 amp draw

Posted: 28 Aug 2019, 14:59
by Teeaitch
The draw is from the starter battery.

Re: 4.5 amp draw

Posted: 28 Aug 2019, 16:27
by itchyfeet
Teeaitch wrote:The draw is from the starter battery.

So likely to be the engine electrics ( which is bad news ), go to the black box and disconnect the round connector with the black wires in it ( the other one does not have a black wire) and measure again.

Next if it's still drawing pull the relay in the black box and measure again.

Re: 4.5 amp draw

Posted: 28 Aug 2019, 16:29
by Cobra88
I would think its the manifold heater and carb heater.

mine draws 3-4 amps until engine is starting to warm up.
Rick

Re: 4.5 amp draw

Posted: 28 Aug 2019, 16:33
by 937carrera
Wiring diagrams here

http://syncrosport.com/info/wiring/

I would look at all the connections on the battery +ve to make sure nothing has been added.

Disconnect the 7 pin plugs in the junction box to isolate the engine wiring from the system

Re: 4.5 amp draw

Posted: 28 Aug 2019, 17:40
by itchyfeet
Cobra88 wrote:I would think its the manifold heater and carb heater.

mine draws 3-4 amps until engine is starting to warm up.
Rick

could be the relay stuck closed circuit ( hence test 2 above) but could also be engine electrics mixed up or bodged, hence test 1 above.

Re: 4.5 amp draw

Posted: 28 Aug 2019, 17:44
by Cobra88
ok no worries

Re: 4.5 amp draw

Posted: 02 Sep 2019, 14:07
by Teeaitch
Thanks for the replies.

I needed to go away in the van last weekend, only a few miles down the road. I made sure that I disconnected the starter battery when I stopped and, obviously, everything was fine when I reconnected to come home after the bank holiday. Disconnected again when I got home.

I decided to go through all the diagnostic stuff again next morning, connected the multimeter and guess what - no drain! (Well there was a bit, a quarter of an amp which is to do with the courtesy light/fag lighter/radio/clock circuit, and no, I didn't have the door open! Pulled the fuse and sort it another day).

I've checked it every day this week and no drain.

I'm wondering whether a year of inactivity had left something stuck open somewhere - the engine has been run from time to time but not been anywhere apart from around the block a couple of times.

As you will have gathered, sparks are not my forte. I'm away again next weekend - don't know whether I have the bottle to trust that whatever it was has sorted itself out so I'll be testing it when I get to my destination - a bit further this time.

I'll also have a look at the suggestions you've made above - thanks for your help.

Re: 4.5 amp draw

Posted: 02 Sep 2019, 19:43
by 937carrera
Well, glad that's all sorted.

I suggest you make this mod https://vwt25.blog/2016/05/19/rewiring- ... e-battery/

Radio, lighter socket (phone charger) and courtesy light all available to use without draining the starter battery