Electrickery

[steffanstringer]

Hi,

anybody got any good pointers (book, website etc.) to help me get my head around the basics of auto electrics (a bonus would be the mysteries of camper electrics!)?

My 1985 Westy keeps draining it's battery and I am looking to figure out what's doing it. I did the stupid thing of rushing out and replacing both the batteries before trying to establish the cause of the problem. I've now got a test meter and understand that I should be able to go through the fuse box somehow, one circuit at a time seeing what's causing the drain.

Any advice (at the Noddy level please - I'm only a biologist ) would be great!

Cheers

Steffan

[Grun]

Hi steffanstringer,

Haynes do a publication, (Haynes 3049) ISBN 1 85960 049 2

which covers an awful lot, but starts with the basics.

They call it 'Automotive Electrical and electronic systems Manual', which I would think is enough to put most people off buying it.

I am going to quote relevant bits from it, to avoid mishaps!!

1. Make sure no accessories are switched on.
2. Set your multimeter to read on the 10 amp setting. (To do this you will probably have to plug the red meter lead into the third socket up from the bottom and rotate the switch to the 10A mark). This is to avoid blowing the internal fuse on the meter which is only rated at a quarter amp and is used to protect the meter on the other DCA (DC amp) settings.
3. Disconnect earth lead from battery and connect your negative meter lead to the battery negative terminal and the positive meter lead to the earth lead you disconnected.
4. The meter reading should not exceed 0.5 amps.
5. If it does check again you have no lights etc. on and remove and replace the fuses one at a time until you find the circuit that is causing the drain.

Do be careful using the meter on the 10 amp setting as it does not have the fuse protection, but at least a replacement is as cheap as chips these days.

A small set of crocodile clips could help to keep the meter leads attached while you check each fuse. The meter will reading will drop when you find the fuse of the circuit at fault.

A 12 volt bulb with a wire to each terminal could be an easier way of checking, at least initially. Just connect between the battery negative and earth (same as for the meter) and it will glow if there is a drain. Small wattage bulb would be best, you can buy little test probes designed for just this purpose.

Check each battery in turn, but I do not know where the Westy fuses are for the leisure battery, just checked my leisure battery and a single fluorescent tube interior light drew about 0.6 amps.

Someone better qualified than me may well come along with further help before long.
You could also look HERE in the wiki top of page.
Mike

[Mocki]

it is often easier to use a good old 21w (Indecator or reverse) bulb and a bit of wire with two croc clips on for the above test,
take the neg wire off the battery in question, and if the bulb lights there is current moving, the brighter the bulb lights the more current is flowing, remove each fuse untill bulb is not lit......

i have several meters, but the bulb is simpler and dont get false readings like cheap meters, and costs less than a quid

[ghost123uk]

Usually my subject but those 2 answers saved me allot of typing

All good advice.

Don't try and start the engine with the meter in the circuit !!

Which battery is draining by the way ?

[Dan Wood]

Also, be aware that even a small drain can leave your bus unable to start.

I had a problem recently where my bus would be dead after leaving it for a couple of days. The drain was only 0.2A, but after 3 or 4 days it left the battery flat.

(Mind you, I'm not sure a 44 Ah battery is what is supposed to be in there! It sounds awfully small to me. M0CKI - have you any idea what a 2.0 CU originally had in?)

[Mocki]

it should have had a 065 ( well the 1980 equiv) which is a 65AmPh
but 075 and 085 fit....

why you not harrassing the 80-90 lot on your island today?

[steffanstringer]

Thanks all for the tips and info - I appreciate your support.

I am going to make the little bulb doohickey just for the hell of it, but in the meantime this is what the multi-meter is reading:-

Main battery:- it first shows 0.15 A, goes to 0.41 A accompanied by a humming noise from somewhere in the front of the van and then down to 0.3 A. I tested this three times with the same results. Battery is 565 A 'cold cranking amps' and is new last Autumn. Can't see a note for the Ah. Calcium technology. Current charge is 12.99 V. This sucker seems to drain down over a couple of days.

Leisure battery:- No current drain at all. Battery is 540 A and is new last Autumn. Can't see a note for the Ah. Calcium technology. Battery current charge is 12.61 V. This battery holds its charge pretty well. It's actually a starter battery and was only thing I could find that was small enough to fit in the pesky space they give you under the seat.

So according to Dan the 0.3 A drain is enough to flatten the starter.

Next step is to monkey around with the fuses and test each circuit one at a time.

Cheers

Steffan

[Mocki]

on your main battery, when you did the test, did you have your keys in your pocket? ie not in the ignition, so everything was off?

first fuse you need to pull is fuse 3, which is the one for stereo and int lights ect......

[steffanstringer]

on your main battery, when you did the test, did you have your keys in your pocket? ie not in the ignition, so everything was off?

first fuse you need to pull is fuse 3, which is the one for stereo and int lights ect......

Yep - keys in pocket. Everything off. Built my little test light and will try fuse three first.

S

[Mocki]

we await the results with baited breath..............:lol

[Dan Wood]

why you not harrassing the 80-90 lot on your island today?

'cos my van's still down at the mechanic's yard.

(Cobwebs on the wheels suggest he's not been too busy with it either! A phone call after the bank holiday methinks.... )

[lloyd]

'cos my van's still down at the mechanic's yard.

(Cobwebs on the wheels suggest he's not been too busy with it either! A phone call after the bank holiday methinks.... )

Bummer you can't be out with other peps

[steffanstringer]

we await the results with baited breath..............:lol

Right then, I pulled out all the fuses under the dash..



Under the drivers seat..



and beside the drivers seat...



Taking all these out one at a time and replacing them always left the bulb alight.

Interestingly the bulb was initially bright, then dimmed, then pulsed. The bright then dim phase matches the observations from the multimeter. Looks like my van's alive - are they supposed to pulse?



http://homepage.mac.com/sstringer/.Movi ... esting.mov

Are there any fuses that I've missed?

Cheers

Steffan

[Grun]

Steffan,

Just a thought, have you got an immobilizer, or alarm fitted? 'Cause my old machine is bog standard, and the only thing drawing from the main battery on mine (ignition OFF) is the clock, analog (quartz?).

So I get no reading at all on the 10 amp multimeter setting, not tried anything more accurate.

The figure of 0.5 amps, that I quoted, is from Haynes and probably refers to a modern vehicle with a lot more bells and whistles than most of our vans sport.

It is also interesting to see the number of UNFUSED circuits shown in Hayne's T3 manual wiring diagram, that are connected to the battery and could cause leakage to earth.

Now while I was labouring at the two finger typing..... you have posted, so here are earlier thoughts.......... and now to digest the latest from you.........

Heavy baited breathing

[Mocki]

is the radio memory wire going to one of the fuses( did it loose its memorys when you did the fuse check?

is there a interior light in the roof( is it a pop top or high top)?

is there any non standard wires going striaght off the battery?

I seem to think the interior lights in a westy do not go through the fuse box, but im not too up on westys......

think id be taking all the fuses out at once, and then checking again,
and also taking the main wires off the battery live one at a time, and re checking..... it must be on one of them!