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Very clear parasitic drain

Chris

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I have been suffering battery failures (flat) on the green 80 since I bought it. I swapped the Optimas for some new standard batteries. Since then the Optimas have actually come up on charge on the bench and have been fine. So I have a pair of perfectly good red tops!

The new batteries have been completely flat a couple of times now after standing for a week. The alternator is kicking out plenty and there are no other odd niggles or anything. I have disconnected all the old sub woofer wiring and so on but still been losing juice. I unplugged the TVSS module and still had losses. So today I had some time to do some tests. With the ammeter across the batteries I got a test result of 4.5 amps with side lights on. Seems fine. Front ones are LED.

With nothing on at all, I am reading 0.13 amps. I set the alarm and it flipped between 0.13 and 0.15 with the flashing LED. With the alarm disconnected it's still 0.13. I pulled all the added wiring from the battery terminals and the fuses out of the aux fuse box. Still reading 0.13. Now I don't really understand these things but .13 of an amp is higher than it should be, yes?

I haven't pulled the alternator plug yet becaue I'm busy, but it's next on the list. But I repeat the alternator is working perfectly. In fact the truck is a joy to drive. But I can't keep punishing the batteries like this. It does one school run per week and other than that rarely turns a wheel. But these are 85 Ah batteries and should not be flat after a week. I have put the CTEK 10 amp charger on them and they are both happily sitting in the float charge mode now. I have used the good old fashioned heated coil battery tester on them and I could have made toast on the element. They held a load no problem. They're nearly new. I have pulled all the dash fuses and put the tester in and none of them are registering any load at all.

I guess the alternator is my last port of call but anyone got any more ideas? There really isn't anything on in the truck. No additional LEDs or anything. Even the stereo is disabled.
 
I don't really understand vehicle electrics but could there be a 'partial' short in the wiring somewhere? dampness maybe but not enough to blow a fuse. :think:
 
OK so it's not the alternator. Positive. I have unplugged the multi plug AND the main lead and I'm still getting 0.13 amps

Well Chas, that's pretty much what a parasitic drain is. It's electricity leaking out of the wires.
 
Well Chas, that's pretty much what a parasitic drain is. It's electricity leaking out of the wires.
Told you I don't really understand vehicle electrics.
3d-paranoid.gif
 
Chris, I had the very same problem. I pulled the DOME fuse and the grey multi plug behind the air cleaner which removed the drain. I also tried disconnecting one battery to see if one was draining the other. Eventually I returned to where I bought the batteries from which was Unipart (not my first choice but still) with my receipt. The fella came out and tested the batteries with his fancy digital tester thingmabob and declared them both duff before handing me two new ones. [emoji3][emoji3][emoji3]

BTW, you could try putting trays under the truck overnight to see if you can catch any of the electricity that's leaking out the wires.[emoji6] just make sure they're plastic trays (Chinese food containers are good), elfin safety an all that!!

Also 0.13A is not out of the ordinary, especially if you have an alarm and clock and a decent stereo. I'd say that wasn't a problem.

2x 85Ah batteries paralleled in theory should be able to feed a drain of 0.13A for 54.5 days although in practice that would be less but not just a week.
 
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130ma still seems quite high IMO although not enough to flatten the batteries in a week. I had a drain of >350ma (duff intake heater relay) which was enough to give starting problems after 1 week with the slightly smaller 75ah batteries. I now get <50ma parked up and locked with the (TVSS3B) alarm set. If you have done the 'permanent live' mod to the electric windows this will add to the drain but by how much I can't remember. I reversed the mod when I was having similar flat battery issues but since then I've replaced the batteries but not bothered doing the window mod again.
 
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Not done the mod. This is a very original vehicle. Don't think it's the batteries. The two red tops did this and I replaced them. They have been in my workshop for a year and still holding enough charge to start the vehicle. So I'd have to rule that out. Couldn't be 4 duff batteries. In a week it will still start but 10 days, nope. Remember they won't be fully drained. We need that 24v to crank it so there might be say 19v in there but it's not enough. It's not like they are dead flat, no dash lights and so on. I just get click click. Touch another battery on and whoomph.
 
I hear you Chris, but It's still worth having them checked. Mine were like that and got slowly worse until they wouldn't hold more than a couple of days but would happily start the truck if given a boost.

My new ones lasted about 2 weeks before setting the alarm off while I was doing front axle rebuild during the winter this year. Then they wouldn't hold so long ( perhaps a week to 10 days) after charging so I disconnected them.

I'm pretty sure taking the DOME fuse out and separating this connector dropped the drain to zero

ImageUploadedByTapatalk1434657251.133603.jpg

So if that doesn't work then there's something else and it will be one of the things left connected. Not that that really helps much I know.
 
As a general rule anymore then about 80ma is excessive, have you tried pulling fuses one at a time and seeing if drops off?
Not knowing the diesels do they have an auxiliary/electric heater?

Heater fan variable resistor, ignition switch (seen a dodgy switch cause a drain) interior light door switch. Water in tow electrics plug.
 
I have put all this in the thread chaps. I have pulled every fuse and put the ammeter in there. I have also tested the batteries with a proper heavy load across them. Not some daft electronic thing, a dirty great big old fashioned tester. I repeat, the batteries before these new ones did exactly the same and they are still sitting there right as a cart one year one starting engines.

Water in the tow plug was something I'd considered Gary. Not looked yet, but it's going to be that sort of thing.
 
That was my next suggestion, (tow plug water) after pulling the DOME and that connector showing what else is left.
 
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Wasn't sure if pulled all of them as said aux fuse box.
Is there any plugs where could isolate say rear end electrics etc?
 
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Not sure where tow plug is wired from, it's a dealer job I think. Don't think there is a front to rear split plug on an 80. That would be a help wouldn't it. Can't see which which plug you mean down by the air filter but I have disconnected both batteries at the +ve and am taking a reading from the pass side battery across the terminal to terminal clamp. All of the service stuff comes off the +ve on the DS battery and that's now not connected to anything at all.
 
Both batteries are connected together so you won't isolate anything by disconnecting one battery. But doing that and putting your ammeter in series as you have, will show you what drain you are getting with whatever you disconnect.

I think the tow plug goes up into behind one of the rear lights, or at least that's where most go if done professionally but it could be anywhere. Just a case of getting under the back of the truck. Before that, just pull the socket apart and check inside. If you do it with the ammeter connected then you should see if you're on to something.
 
The plug is directly behind the battery between the air cleaner and the inner wing. It's quite chunky, probably one of the biggest under the bonnet.
 
Both batteries are disconnected. The only connection to anything is the earths and the ammeter between the clamp and terminal on one battery. I need to go into the plug for a look for sure. But this truck doesn't even get driven in the rain and visually it looks fine. But I have pulled these before and had the innards just fall out.
 
Yes, all the car runs from both batteries, perhaps I read it wrong but it looked like you were hoping to isolate some part of the car by disconnecting one or other battery. Anyway, putting the ammeter in between the battery and the car will show the whole drain. I find if you can get someone useful to look at the ammeter while you unplug things and or waggle wiring systematically, you can often see the meter jump about or even change reading fairly definitely when you come up against something.

Problem is you can find lots of insignificant small drains that all mount up to the total without finding the 'smoking gun' as it were.

Not at all easy but tackled systematically you stand a good chance of finding it.
 
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I hate vehicle wiring because i've torn many a bike apart wrapping each and every wire with tape in frustration searching for a short , and every single time i've fixed the problem by accident removing the headlight looking for more wires to wrap . I will lay odds its a perfectly good connection in an exterior light causing the drain .
 
I could understand an Interior light, as these have permanent + connected to them, so may be worth a look but then the DOME fuse does these. Wouldn't exterior lights be without power with the ignition off?

Items that are powered all the time are my first suspects. The other thing that's just struck me Chris, have you had any water getting in up front through the windscreen and possibly leaked onto a relay or other control unit causing some leakage? I'm doubting this TBH as you say it doesn't go out in the rain. But car washing? Jet wash?
 
Doesn't get washed either. Like I said, it's been doing this since I got it over a year ago. I thought it was batteries so swapped them. But until recently it's been driven a couple of times a week. Only now is it not being used and I have been monitoring it since they were flat again for the first time in a while. So what ever is causing it is not new.
 
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