Am I doing something wrong here...

[killerme]

Westy T25 1989
My main battery is always draining. When I test it for draw it doesn't show any leak at all (disconnect the neg battery point and link with a multimeter set for milliamps). However I suspect that it may be because when it rains there is some water where the battery sits.

However, I thought it wise to disconnect my leisure battery while I was doing this test and in the process discovered that there is a 10.5 v drain off that! But this battery has never run down since I've had it. What's going on? I disconnected all the fuses one by one and the 10.5v didn't disappear with any of them.

Just to recap - I disconnect the negative terminal then connect one side of the multi meter to the terminal post and the other to the to disconnected cable after setting the MM to milliamps. In the case of the leisure battery I don't need to set it to milliamps because it shows a drain set at 20v.

Is there something I don't know about or am I doing something wrong?

[Mocki]

Sometimes digital multimeters make things less obvious, and because they take no power to measure , they float and give readings that are not always accurate

Sometimes the old fashioned ways are better ..... instead of using the multimeter, use a brake light bulb instead , the brighter it lights the bigger the drain ... just insert it between the neg post of the battery and chassis earth . Things maybe will become clearer ?

[ZsZ]

You can measure draw by measuring Amps in the circuit - you connect the multimeter series in the circuit use the Amps setting of the multimeter
or you can measure draw by measuring voltage drop between contact points - you connect the multimeter parallel in the circuit and use the Volts setting of the multimeter.
Measuring the amps is the easiest but you can only measure a relatively low range depending on your meter.

Finding parasitic draw can be a PITA

First fully charge up both batteries out of the circuit (neg points disconnected or removed from the vehicle) best to do it with a smart charger as you cannot overcharge batteries with those.
Wait a few hours or a day to let the battery settle. measure the voltage of the batteries. Should be over 12,6V. If any of them is lower then that, the battery is shot and can drop voltage by itself.

First put back the starter battery and measeure the draw on that.
Measure the draw, but instead of MiliAmps, switch to Amps. Be sure doors are closed or interior lights are switched off key is out. The draw should be under 1 Amps, best if its under or around 0.1A. If its over 1 then start pulling fuses from the fuse panel one by one. Draw should drop at one then you just need to check what is connected to that fuse. (usually alarm or stereo are the sinners) If there is no drop in the draw then something unfused went wrong. (ECU, alternator, etc., something in the engine bay)

Then disconnect the main battery and put back the leisure battery and measure the draw on that.
Still use the Amps range and start pulling leisure fuses. Apart any aftermarket or PO DIY things, fridge and built in battery charger are the suspects.

[killerme]

Cheers for the comments. I just bought a 2nd hand beha-amphrobe on ebay as perhaps my MM isn't the best and then I'll follow your instructions as given. Thanks again.

[killerme]

No something's not right here. Both batteries fully charged. Starter battery at 12.9. When I link the neg post with the cable with the multimeter set for 20 volts, it shows 12.9 still. (The positive cable still connected to the positive post).

The same with the leisure battery which is charged to 13

This isn't right is it?

[killerme]

Ah! I just read something which may explain my problem. I thought that I shouldn't connect the MMeter with amp settings because 12v would blow it. But this is wrong thinking, right? The amp setting measures different things. It doesn't mean less - just different.

[Mocki]

You are getting very. Confused I think .

If you put your meter between the battery neg and the body of the van it’s reading the battery voltage because you are completing the circuit .
Put the meter down and use a bulb . It will show your drain

[killerme]

ok I'll try that

[killerme]

well Steve
it seems like the old ways are the easiest and the best! A dim red glow from the light identifies the problem, and the culprit appears to be the 15amp (third along) fuse for:
reading lamps
interior lamps
vanity mirror
clock
fag lighter
radio

I'm guessing the radio which I put in when I bought the van. Now I have to find a solution.

Your help was really appreciated

[killerme]

Mmmm! The live wire (red) from the radio is connected (with the yellow) to the permanent live in the cab. However, I need to connect the yellow to an ignition live. But there isn't anything except the lights that work off the ignition. I'm looking at the back of the display unit but I don't fancy cutting into those guys randomly!!

Any suggestions beside disconnecting the yellow permanently and finding a station every time?

[Mocki]

You are very welcome !

Ok, there is no AUX position on a T25 , the key is either off , on , or turning the engine over , so the choice for stereo supply is limited to When the engine is running , or all the time .

Normal procedure is wire the memory wire to the leisure battery , and the power feed to the ignition switched feed , or to the leisure battery via a toggle switch you install in the dash ....

[killerme]

Sorry yes I got that the wrong way round. Yellow to a permanent feed, red to ignition live. But its that last bit...where is there an existing feed that I can link the red to? I don't have any devices in the cab that only work when the ignition is on - other than the lights.

[Mocki]

The existing radio loom should be there?
Depends on what age your van is, I’ll assume it’s a late ( blade style) fuse box , and there is a spare ignition only switched out put on the top right at the back , you be able to test for it with your meter .
Like I said, if you have a leisure battery then feed the radio from there, it will stop any embarrassment when you want to start up !

[killerme]

that's brilliant news. I'll check that out. Perfect. I've discovered in this exercise that, for some reason, the interior van lights eg over the cooker on either side are all running off the starter battery. I never knew that. Obviously they aren't supposed to be. I'm not even sure what the leisure battery is doing - if anything. No wonder it never runs down! But that is for another day.

[Mocki]

Hahaha.... yep, that will be because whoever converted your van was lazy and used the existing van interior lighting loop for the camper interior lights .... however, it’s easy to solve, take out fuse 3 , and run a fused live from the leisure battery with a male spade on the end to the fuse box and plug it in the lower hole the spade fuse was in .... everything from that fuse3 position is now running on the leisure battery . Simples !