Mystery current drain

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MagicWagon
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Mystery current drain

Post by MagicWagon »

I've found that when the key is in the first position (acc? - engine not running) that there is a current of 2.7 amps being drawn. I've tried disconnecting everything, including removing all fuses and disconnecting the leisure battery. I disconnected the very thick +ve main battery cable and found the current is going through the thickish red cable which connects to the +ve terminal via a ring terminal and nut. Apart from calling in an expert, is there anything else I can check? Also, does 2.7 amps point to, or rule anything out ? Many thanks.
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Da dan
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Re: Mystery current drain

Post by Da dan »

Alternator?


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itchyfeet
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Re: Mystery current drain

Post by itchyfeet »

not a mystery
you have unfused circuits also
ignition coil is one.
not sure what else on an Aircooled.

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davidoft1
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Re: Mystery current drain

Post by davidoft1 »

What is it you’re trying to achieve? With the ignition on
The ignition system will be live

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bigherb
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Re: Mystery current drain

Post by bigherb »

There isn't normally an accessory position, first position switches on the ignition, the current draw is from the auto chokes and carb solenoids.
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Mocki
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Re: Mystery current drain

Post by Mocki »

as has been said, there is no aux position on a 25, thats ignition ON
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MagicWagon
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Re: Mystery current drain

Post by MagicWagon »

Thanks for the information and sorry for the incorrect terminology.
I thought 2.7Amps seemed like quite a lot, and thought that would drain the main battery quite quickly if the engine wasn't running.
Would the auto chokes and carb solenoids draw as much as that ?
Cheers.
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Mocki
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Re: Mystery current drain

Post by Mocki »

yes, easily .
the ignition should never be on in the run position when the engine isnt running .
Steve
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MagicWagon
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Re: Mystery current drain

Post by MagicWagon »

Many thanks for that. It puts my mind at rest, and very useful to know as I could easily have drained my battery accidentally.
Cheers.
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bigherb
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Re: Mystery current drain

Post by bigherb »

Why do you need to have the ignition on without the engine running?
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MagicWagon
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Re: Mystery current drain

Post by MagicWagon »

bigherb wrote:Why do you need to have the ignition on without the engine running?
In case I want to sound my horn :D
But seriously, I have my stereo wired to stay on when you turn the engine off, and to go off when you take out the key.
In hindsight, not the best idea if it is drawing 2.7A.
I also have it wired with a switch so I can use the leisure battery for the stereo, but that way I have to physically switch it off, rather than just taking the key out.
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937carrera
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Re: Mystery current drain

Post by 937carrera »

Have a read here

https://vwt25.blog/2016/05/19/rewiring- ... e-battery/

Because yours is an early van with ceramic fuses you need to make fuse 7 or 8 (I think) to be your permanent live from the leisure battery.

Radio whenever you want

Starter battery not getting drained while listening on a night

Easy & cheap to do.

:ok
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MagicWagon
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Re: Mystery current drain

Post by MagicWagon »

Thanks for the link. As far as I can understand, that wouldn't give me one of my key requirements, which is for the radio to come on automatically when I start the engine.
The set up I currently have gives me everything I want, including auto on/off and ability to run from the leisure battery. I will just have to be careful not to leave the ignition in the on position for more than a couple of minutes, now I know about the current draw.
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Mocki
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Re: Mystery current drain

Post by Mocki »

if you add a simple 5pin auto relay to feed your radio you can have what you want without the danger of killing your main battery or your coil

connect radio to pin 30
connect feed from leisure battery to pin 87
connect feed from main battery via ignition switch to pin 87a

connect neg to pin 85
connect a always live switched from your control switch to pin 86

when control switch is on radio is on , powered from leisure battery , switch off and radio only works when ignition is on red lights, key off, radio off
Steve
tel / txt O7947-137911
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MagicWagon
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Re: Mystery current drain

Post by MagicWagon »

Unless i'm mistaken, that's pretty much what I've got already, except that won't allow me to use the stereo when the ignition key is not on (e.g when camping), and therefore, I also have a physical switch which can be used to bypass the relay and switch the stereo on whenever required.
It's shown somewhere in my wiring diagram attached. I must tidy up that diagram one day, I know it's a mess, but that's just how it has evolved as I rewired the van.
Campervan Rewire3.jpg
My rewiring diagram
(125.69 KiB) Downloaded 7 times
1983 2.0L Air Cooled Devon Moonraker

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