Van Battery Drain

[prog99]

Been looking into causes of a battery drain. Vw dealer say it’s down to the rear alarm sensor and won’t touch it as it’s been tinkered with or removed by the converters(who aren’t local) Carista shows up this sensor error.
Anyway, here’s the last few days charts.
6th is with a fully charged battery and the bm2 getting attached.
7th I was on and out the van a couple of times. Moved it twice to free up space on the drive.
8th(today) is the interesting one. After staying static for 2 days it looks like the van had a party today.
Anyone seen anything like this? It was cold today but seems odd to me. It’s similar behaviour to what the dealers saw. They also found no drain until it was with them for several days.
Thanks, Mike

 

[Pete C]

What error is Christa showing ?
Not sure what you mean by rear alarm sensor ?
Something happened around midday on the 8th, what equipment do you have attached/installed ?

Cheers,

Pete

 

[prog99]

Hi Pete, its this one which the dealers say is the rear internal alarm sensor.

Central electronics
Part #: 7E0937090D
Component: BCM PQ25 Max4
Software version: 0762
ASAM/ODX identifier: [none]
Coding: A0AC393A0A61301193284F746CEB8EF40F84710F60CC6D60330400230840 (hex)
Fault codes:
03156 Sensor for Warning System Theft

Theres a sterling b2b charger for the leisure system attached and also a connection to the sargent system too from the van battery. However I'm fairly certain those two are innocent as I've seen drain before when they are disconnected from the van battery. Other than that nothing.

 

[Pete C]

Someone with more knowledge than me may be able to help with that error code - what did the converter remove ?
The error code could of course be nothing to do with the current drain. I think you may need to work through this wire by wire.

Pete

 

[prog99]

Same sensor thats discussed here https://www.t6forum.com/threads/ala...s-windows-ajar-thread-merge.21026/post-314478

Still really puzzled as to why the van seemingly was quietly idling away doing very little and then a spurt of unexplained activity. Will have a poke around later if it warms up here.

 

[JasonW]

Whats the dip at 8am on the 7th...?

Looks like key fob press activity... but no start until 12 onwards

 

[prog99]

Yup, nipped in and out the van.

 

[JasonW]

If i just looked at the data from the 8th with no other cause for concern i wouldn't be that bothered....

There is small flucuations in the voltage feedback or whats interpreted by the BM2 on the 8th...

Could be poor connecton of the BM or noise pick up within the BM...

I see a gradual trend down on mine when left for a couple of days with small 'blips' albeit not as long as yours....

If you think you are getting battery drain you probably need to put a current clamp on it and see what amperage its drawing when idle....

 

[mmi]

Been looking into causes of a battery drain. Vw dealer say it’s down to the rear alarm sensor and won’t touch it as it’s been tinkered with or removed by the converters(who aren’t local) Carista shows up this sensor error.
Anyway, here’s the last few days charts.
6th is with a fully charged battery and the bm2 getting attached.
7th I was on and out the van a couple of times. Moved it twice to free up space on the drive.
8th(today) is the interesting one. After staying static for 2 days it looks like the van had a party today.
Anyone seen anything like this? It was cold today but seems odd to me. It’s similar behaviour to what the dealers saw. They also found no drain until it was with them for several days.
Thanks, Mike

Excluding the party, why do you think there is excessive drain? How deep was the party - tap and drag a cursor on the screen to see actual voltage readings.

 

[JasonW]

The other thing is your battery... How old is it...? What make is it..?

It might be that its just not that effective anymore of holding charge if its old...

You need to determine idle current draw to say for sure if something is constantly drawing from the battery....

If its quite an old unit, you could try and desulfate it and condition it using a smart charger....

 

[prog99]

Hi Jason, its brand new so unlikely to be the cause (I pancaked the old one quite spectacularly)

 

[prog99]

Excluding the party, why do you think there is excessive drain? How deep was the party - tap and drag a cursor on the screen to see actual voltage readings.

Hi @mmi , it dropped from 12.6 to 12.46 during the vans illegal party and then a small rise followed by a drop and steady state of 12.38 or so after that. It did warm up form -9 to +2 today.

 

[JasonW]

Ah ok... Well those voltages sound ok to me... after a charge and when sat idle mine trends down from 12.6 to 12.4.... within a couple of days and keeps trending slowly down if left idle..
.
So yours from what you have shown us so far doesn't sound too bad....

 

[mmi]

Hi @mmi , it dropped from 12.6 to 12.46 during the vans illegal party and then a small rise followed by a drop and steady state of 12.38 or so after that. It did warm up form -9 to +2 today.

Thanks. Overall it looks normal to me - although the party looks interesting. Do you have any Bluetooth gadgets in the van which might have looked for a casual relationship from bypassers? BM2 does that but it wouldn't cause quite that big voltage drop.

after a charge and when sat idle mine trends down from 12.6 to 12.4.... within a couple of days and keeps trending slowly down if left idle..

That's what I see, too.

 

[prog99]

Looks like it’s sort of settled down now. Did have a short trip in it yesterday.

Part of the reason I flapped is flattening the old battery and then obsessing over checking the new one with a multi meter(ie opening a closing the van several times a day may have contributed)
Having said that vw were sure the missing rear alarm sensor was contributing some drain.

It’s a pretty quiet street so not sure what other Bluetooth interaction there might be that wouldn’t be transitory but it’s an interesting idea.

 

[JasonW]

Yeah... the bluetooth signal can be a little jumpy... and i wouldn't read too much into it,,,

This pinged to my phone this morning just walking past the van... no activity... .

It wasn't a real voltage increase.... but a fake reading like 'bluetooth connection noise'

 

[prog99]

Dropped continuously to 12.2 overnight. Got a fault code now as well but Carista doesn’t give any more detail.

Battery regulator
Part #: 7E0907534
Component: Batt.regelung
Software version: 0762
ASAM/ODX identifier: [none]
Coding: 030B7A73 (hex)
Fault codes:
02256 Quiescent current

 

[Qnapper]

I would say that your battery is dead and not holding the charge anymore. It will charge fine on veh running or EHU, but as soon as you remove the charging it will drop from 12.6+ to nothing in no time. Get battery checked and/or replaced.

 

[JasonW]

We suggested battery earlier in the thread, but prog99 has said its brand new....

Can you get a current clamp on it when idle to measure current draw...?

 

[mmi]

Dropped continuously to 12.2 overnight. Got a fault code now as well but Carista doesn’t give any more detail.

Battery regulator
Part #: 7E0907534
Component: Batt.regelung
Software version: 0762
ASAM/ODX identifier: [none]
Coding: 030B7A73 (hex)
Fault codes:
02256 Quiescent current

So - this fault was not there yesterday? Did you have the Carista plugged in overnight? It draws approx. 40 mA.

More:

https://www.t6forum.com/threads/quiescent-current-battery-regulator.284/