Battery drain issue [Resolved]

[Speedymaiden]

I seem to have a battery drain on my 2016 T6 150 highline as it struggles or fails to start after about 6-7 of not being used. Firstly I believed it to be the battery, so had a brand new AGM battery installed and coded to the van but again after 6-7 days I’m getting the same issue. It appears to be charging fine at 14v when running so sort of rules the alternator out and sits at about 12.4-12.5v after use. The van has no leisure electrics installed and the only thing connected to the battery is a battery monitor which I installed to see how many bolts it’s dropping a day which is about 0.2v a day. I’ve done a parasitic draw test across all fuses in the centre dash, engine bay and the large fuses under the battery but all fuses are reading 0mv. I then put my multimeter between the neg terminal and neg lead to find I have about 0.8 amp constant drain I’ve then proceeded to pull every fuse in centre dash and engine bay but the amps didn’t drop, that was until I pulled the 125A fuse on cable 2 under the battery. Reading through wiring diagrams this feeds fuse holder C in centre dash fuses 1-17. Now I re tested these ones and the 4 larger slow blow fuses but again nothing reducing the drain, this is where is gets a bit weird, when I pulled fuse 4 the large 40A slow blow nothing happened but after a while the drain seemed to settle at about 0.009amp when put back in it woke back up and went to about 0.8-1 amp and then eventually settled at 0.009A which seems a sufficient amount of drain with the alarm etc. I repeated this and also removed 3 other fuses 23,38&39 and the same happened settling at 0.009A. At this point I couldn’t get my head round it locked the vehicle and gave in. I’ve checked the battery today and seems to have dropped another 0.2v so there must still be a drain.

Has anyone had a similar issue or know if I’m following the correct path as I’m at a bit of a loss now. Fuse 4 seems to be a feed to the 645 relay in fuse holder C which is a starter inhibitor relay I believe, I was wondering could this possibly be faulty? Do relays drain batteries or is there something else it could possibly be ?

Any good suggestions would be greatly appreciated

 

[mmi]

I then put my multimeter between the neg terminal and neg lead to find I have about 0.8 amp constant drain

Did you close all the doors and lock the van (including bonnet latch) for the measurement? Otherwise BCM stays alive quite some time.
In the picture the multimeter is at AC-current, or? 9 mA would be abnormally low for T6.
Typical/normal drain/quiescent current for T6 is 30-40 mA - for a locked van.
Have you checked fault codes - the battery management will trigger a fault code for excessive drain (at approx. 50 mA continuous).

struggles or fails to start

You mean it won't crank?

sits at about 12.4-12.5v after use. The van has no leisure electrics installed and the only thing connected to the battery is a battery monitor which I installed to see how many bolts it’s dropping a day which is about 0.2v a day.

What's the voltage next morning - after 12 hour rest? Can you get the reading without unlocking the van?

 

[Speedymaiden]

Did you close all the doors and lock the van (including bonnet latch) for the measurement? Otherwise BCM stays alive quite some time.
In the picture the multimeter is at AC-current, or? 9 mA would be abnormally low for T6.
Typical/normal drain/quiescent current for T6 is 30-40 mA - for a locked van.
Have you checked fault codes - the battery management will trigger a fault code for excessive drain (at approx. 50 mA continuous).

You mean it won't crank?


What's the voltage next morning - after 12 hour rest? Can you get the reading without unlocking the van?

Yes I closed all doors and latches locked it and left for about 30 mins to shutdown and was drawing 0.8A across the neg terminal to neg lead

I did a scan a few days ago with nothing to show but haven’t done one since so unless anything else has appeared since

If left for about 7 days it will either crank sluggish and start or will attempt to crank and not start lights flicker etc due to the battery being low

It will also display the 12v system low on the odd occasion

When I left the van last night after I had been playing around for a few hours it was sat at 12.18v as of now according to the BM it’s now 12.1v

 

[mmi]

Yes I closed all doors and latches locked it and left for about 30 mins to shutdown and was drawing 0.8A across the neg terminal to neg lead

After locking the van the current should go down to 30-40mA in approx. 60 seconds.

Perhaps something useful here:

Trouble turning over

Hi all I have had an ongoing issue with my van struggling to turn over, this all started towards the end of last year when I went on holiday for 2 weeks. When I returned I started the van and although it started it struggled turning over, I didn't think a lot of it as the van had been stood...

www.t6forum.com

Has the new battery been fully charged at some point?

Can you get a "scan" of van's BCM and Battery management (controllers 09 and 61)? I'm to see curious what's the software version of them?

Trickle charge?

No not battery related, it was to do with control module(s) not shutting down when the vehicle was locked up You don't remember the details? My old T6 came from the factory with BCM 7E0 937 090 H80 0733 and at some point late 2016 it was updated to 0736. Unfortunately I wasn't then quite up to...

www.t6forum.com

 

[Speedymaiden]

Some very useful threads there I will get the van on VCDS tomorrow and get you an update on the BCM I haven’t owned the van from new so I’m unaware of any recalls it may have gone in for in someways fingers crossed it just needs an update

 

[Dellmassive]

Can you post your BM2 plots?.

Also less than 50mA is normal. (We'll about 30mA when sleeping).

0.8A is way to high.

.....


Thats normally dash cam, usb charger type loads....


Have you access to a thermal camera?.... That may help you see what's powered after a night of sitting about?

 

[Speedymaiden]

After locking the van the current should go down to 30-40mA in approx. 60 seconds.

Perhaps something useful here:

Trouble turning over

Hi all I have had an ongoing issue with my van struggling to turn over, this all started towards the end of last year when I went on holiday for 2 weeks. When I returned I started the van and although it started it struggled turning over, I didn't think a lot of it as the van had been stood...

www.t6forum.com

Has the new battery been fully charged at some point?

Can you get a "scan" of van's BCM and Battery management (controllers 09 and 61)? I'm to see curious what's the software version of them?

Trickle charge?

No not battery related, it was to do with control module(s) not shutting down when the vehicle was locked up You don't remember the details? My old T6 came from the factory with BCM 7E0 937 090 H80 0733 and at some point late 2016 it was updated to 0736. Unfortunately I wasn't then quite up to...

www.t6forum.com

So I got the van on VCDS today according to the thread their BCM no. was 7E0 937 090 H80 0733 and updated to 0736 however my no. Is 7E0 937 090 B am I missing something here ?

Here is what VCDS controllers 9 & 61 are displaying it also came
up with 2 faults on controller 9 & 8 faults on controller 61

Could any of these be caused by the issue and do they possibly cause the issue ?

See the attached photos

 

[Speedymaiden]

Can you post your BM2 plots?.

Also less than 50mA is normal. (We'll about 30mA when sleeping).

0.8A is way to high.

.....


Thats normally dash cam, usb charger type loads....


Have you access to a thermal camera?.... That may help you see what's powered after a night of sitting about?

The plot doesn’t show much as I only connected it after I re installed the battery after a full charge the other day but you can slightly see that the voltage is decreasing due to the drain, just before starting it this afternoon it was down to 12.05v

I haven’t got access to a thermal camera but I have felt for warmth on all the relays I can find including the ones under the battery as well as the battery monitor on the battery and none feel warm to the touch

 

[Dellmassive]

The thing to do now is log all the codes.

Then clear them..

Then see what comes back over the next 48hrs. With a test drive and sitting about and let the van sleep etc..

 

[Dellmassive]

Are you 100% sure there is nothing plugged in the obd2 port.

Or no USB chargers installed.

Or dash cams etc etc..


I had the quessent power draw too high when I left the Carista or other BT dongle plugged in over night.

 

[Speedymaiden]

Are you 100% sure there is nothing plugged in the obd2 port.

Or no USB chargers installed.

Or dash cams etc etc..


I had the quessent power draw too high when I left the Carista or other BT dongle plugged in over night.

No it doesn’t have anything plugged in, it hasn’t had any extra USB chargers or dash cam installed it’s just a manufacturer standard van, it’s driving me mad, there is the standard cigarette lighter in the centre 12v port but surely it’s unlikely to be that

 

[mmi]

according to the thread their BCM no. was 7E0 937 090 H80 0733 and updated to 0736 however my no. Is 7E0 937 090 B

No software update for this one - full no. actually is 7E0 937 090 B H81 0744, thus newer version than the suspect.

As @Dellmassive above the way forward is to save all the codes, then clear them and monitor what comes back..

Good thing is the van already knows there indeed has been drain - the fault has been triggered 103 times, which probably means 103 driving/rest cycles. I believe the fault is logged only once per "rest" cycle.

 

[Speedymaiden]

So today I started the van after no use for 36 hours, the battery voltage had dropped as I expected to 12.05v it started and I gave it a little run. I hooked up VCDS and got a repeat of the faults I initially had as I also suspected.

I decided to start from scratch and eliminate a few things I firstly hooked up the multimeter and bypassed the negative battery monitor cable and was reading a 0.153A draw when locked so it’s not that. I then pulled every relay I could find including all the ones under the battery and all the fuses in fuse holder B but again just sitting at 0.153A.

I then went back to what I found the other day by removing cable SA2 under the battery which dropped the drain to 0.026A, this cable feeds power to fuses 1-17 on fuse holder C. I started pulling the fuses to find SC4 (fuse4) dropped the drain to 0.026A, now fuse 4 is T30 supply to SC22,57,58,59, SD1-6 I pulled all these with SC4 back in place but nothing happened the drain only drops when SC4 itself is pulled. I’ve looked through the wiring diagrams and from what I can work out SC4 feeds J207 starter inhibitor relay which I pulled and still showed 0.153A draw, following the wiring it does seem to go through the ignition switch and a few other fuses to cable SA9 which when I removed other that, other than setting the alarm off killed the drain to 0.026A so now I’m scratching my head could it possibly be ignition switch would that cause a drain ? I am a bit lost as to where to go from here

 

[Speedymaiden]

UPDATE FINALLY SOLVED!

So I’ve finally solved the battery drain issue, it was a faulty ignition switch! After tracing the wiring diagram from SC4 fuse the only component it could possibly be was the ignition switch, I bought a brand new one for £15, replaced it today which is a really simple job and bingo the amp drain on the multimeter with the vehicle locked has gone. I’m assuming it had a short or something inside but had no obvious symptoms it was faulty so may be something to be aware of if anyone is having battery draining issues.

 

[RedPete66]

UPDATE FINALLY SOLVED!

So I’ve finally solved the battery drain issue, it was a faulty ignition switch! After tracing the wiring diagram from SC4 fuse the only component it could possibly be was the ignition switch, I bought a brand new one for £15, replaced it today which is a really simple job and bingo the amp drain on the multimeter with the vehicle locked has gone. I’m assuming it had a short or something inside but had no obvious symptoms it was faulty so may be something to be aware of if anyone is having battery draining issues.

Good to know. I have slow drain issue but don't have the skills to hunt it down like you have. might be worth trying this if it gets problematic. Cheers.

 

[RedPete66]

A really basic question on the subject. Can I attached a trickle charger to the battery/neg earth point without disconnecting anything from the battery?

 

[Dellmassive]

A really basic question on the subject. Can I attached a trickle charger to the battery/neg earth point without disconnecting anything from the battery?

No.

You need to use a chassis ground. So you don't bypass the battery power monitor.


You can use the light bracket bolt next to the battery!

 

[RedPete66]

Yes that’s understood. I meant do I need to disconnect any of the battery cables to avoid blowing fuses etc?

 

[Dellmassive]

Nope.

Provided you have a AGM/SLA compatible smart charger.

..

See the charger section here..

Dellmassive’s "How I Done It" blogs.

-- Dellmassive`s -- "How I Done It" -- thread -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

..

 

[Lukefx]

Did you close all the doors and lock the van (including bonnet latch) for the measurement? Otherwise BCM stays alive quite some time.
In the picture the multimeter is at AC-current, or? 9 mA would be abnormally low for T6.
Typical/normal drain/quiescent current for T6 is 30-40 mA - for a locked van.
Have you checked fault codes - the battery management will trigger a fault code for excessive drain (at approx. 50 mA continuous).

You mean it won't crank?


What's the voltage next morning - after 12 hour rest? Can you get the reading without unlocking the van?

@mmi sorry to jump on an old post but I'm trying to find a battery drain on mine, the amp draw is around 1.7a which seems really high but I didn't isolate the bonnet latch, just had a look and you can't disconnect the wiring, is just pushing the latch down with a screwdriver good enough?