Has Anyone Got The "second Maintenance Free Battery" Option?

[Deleted Member]

I'm in a world of blissful ignorance, I have the factory leisure battery and have no idea what battery type is fitted, it's always used when we we camp and has managed 3 days of ipad/iphone charging, run a 12v tv, led ceiling lights etc and not gone flat yet.

If there are any issues with the battery not charging etc then it can go back to the dealer for repair or replacement.

 

[Graham Jones]

Varta AGM 110ah under passenger seat.
MOLL EFB+70ah... engine bay.

 

[Dellmassive]

Varta AGM 110ah under passenger seat.
MOLL EFB+70ah... engine bay.

Single passenger seat?

A 110ah won't fit under a twin bench?

 

[Jimmi]

I'm in a world of blissful ignorance, I have the factory leisure battery and have no idea what battery type is fitted, it's always used when we we camp and has managed 3 days of ipad/iphone charging, run a 12v tv, led ceiling lights etc and not gone flat yet.

If there are any issues with the battery not charging etc then it can go back to the dealer for repair or replacement.

Hi, where are the 12 volt outputs for the leisure battery? I've ordered a Kombi Highline with the second battery too.

 

[Dellmassive]

Hi, where are the 12 volt outputs for the leisure battery? I've ordered a Kombi Highline with the second battery too.

The top of the dash on ours

 

[Jimmi]

The top of the dash on ours

is that standard?

 

[Graham Jones]

Single passenger seat?

A 110ah won't fit under a twin bench?

Yes ...a single passenger seat.......
and only 12v outlet (except for cigarette lighter) is on top of dashboard.

 

[Deleted Member]

Hi, where are the 12 volt outputs for the leisure battery? I've ordered a Kombi Highline with the second battery too.

I honestly don't know where they are from the factory, my van was converted straight after it arrived and additional sockets were fitted in the middle and rear.

 

[Jimmi]

I honestly don't know where they are from the factory, my van was converted straight after it arrived and additional sockets were fitted in the middle and rear.

The brochure and dealer are very vague about the options. I’ve got a feeling that the battery will just be connected to a fuse box / distribution box and that will be it.

 

[Deleted Member]

Mine is under the passenger seat, it's a single so you can't just pop it open and see where it's connected to like you can on the twin seats.

 

[Jimmi]

Mine is under the passenger seat, it's a single so you can't just pop it open and see where it's connected to like you can on the twin seats.

Thanks for the info, I dont suppose you have any pics of the setup? I was also interested to read that your 2nd battery charges fine despite others saying that the split charge relay doesnt actually work properly?

 

[Phil_G]

I was also interested to read that your 2nd battery charges fine despite others saying that the split charge relay doesnt actually work properly?

It all depends on what you mean by 'properly'. It will charge, but....
The starter and leisure batteries can be in hugely different states of charge:
1) say the van has been left for 3 weeks, starter battery drained, leisure battery full, on float from a solar panel.
2) Leisure battery drained after a weeks camping, starter battery full from trips to the shop
3) Leisure battery 100% full from solar, starter battery held at 80% by the battery control unit.
4) Both batteries drained, most likely to a different degree

All the VW "aux battery isolation relay" does is to connect the two batteries in parallel, regardless of any extremes of individual state.

On top of this you have 'Bluemotion' where huge alternator demands are made when braking and consequent higher voltages are applied to the paralleled batteries, and where the BCM actively allows the batteries to drain to 80% when not braking.

Crucially, all the singular BCM has to go on when it starts a charge cycle is the resulting voltage from this mismatched but paralleled pair, and its estimate of the starter-battery state-of-charge from the current monitor. It has no means of judging the state-of-charge of the paralleled leisure battery. With all this in mind you can see how one BCM and a split-charge relay cannot possibly 'optimally charge' both your starter and leisure batteries!

Cheers
Phil

 

[Jimmi]

It all depends on what you mean by 'properly'. It will charge, but....
The starter and leisure batteries can be in hugely different states of charge:
1) say the van has been left for 3 weeks, starter battery drained, leisure battery full, on float from a solar panel.
2) Leisure battery drained after a weeks camping, starter battery full from trips to the shop
3) Leisure battery 100% full from solar, starter battery held at 80% by the battery control unit.
4) Both batteries drained, most likely to a different degree

All the VW "aux battery isolation relay" does is to connect the two batteries in parallel, regardless of any extremes of individual state.

On top of this you have 'Bluemotion' where huge alternator demands are made when braking and consequent higher voltages are applied to the paralleled batteries, and where the BCM actively allows the batteries to drain to 80% when not braking.

Crucially, all the singular BCM has to go on when it starts a charge cycle is the resulting voltage from this mismatched but paralleled pair, and its estimate of the starter-battery state-of-charge from the current monitor. It has no means of judging the state-of-charge of the leisure battery. With all this in mind you can see how one BCM and a split-charge relay cannot possibly 'optimally charge' both your starter and leisure batteries!

Cheers
Phil

Thanks for the info..... I’ll just use the system as it is and see how I go. I’ll only be using it for an inverter to charge batteries. I’m not planning on camping so no fridges and tv’s etc. If it works it works if it doesn’t I’ll address the situation.

 

[Deleted Member]

Thanks for the info, I dont suppose you have any pics of the setup? I was also interested to read that your 2nd battery charges fine despite others saying that the split charge relay doesnt actually work properly?

Sorry, it's under my single passenger seat, you can't get to it without unbolting the seat.

It's good info from @Phil_G , but it seems crazy that VW didn't think of this when they designed the leisure battery installation.

All I can say is that, so far, I've had no battery issues and we camped 4 times this year and gave the leisure battery a decent work out.

 

[Phil_G]

VW are fully aware of course, but they consider that maintaining the secondary battery somewhere between 80% and 'full' is ok
Their method is just a poor compromise in what is otherwise a technologically advanced vehicle

 

[Jimmi]

VW are fully aware of course, but they consider that maintaining the secondary battery somewhere between 80% and 'full' is ok
Their method is just a very poor compromise in what is otherwise a technologically advanced vehicle

It’ll be interesting to see how good or bad it is, because I was told I couldn’t fit a SCR in my Sprinter and the battery to battery system was too expensive so I didn’t bother. Had I known it was good enough for VW I’d had done it

 

[Graham Jones]

It all depends on what you mean by 'properly'. It will charge, but....
The starter and leisure batteries can be in hugely different states of charge:
1) say the van has been left for 3 weeks, starter battery drained, leisure battery full, on float from a solar panel.
2) Leisure battery drained after a weeks camping, starter battery full from trips to the shop
3) Leisure battery 100% full from solar, starter battery held at 80% by the battery control unit.
4) Both batteries drained, most likely to a different degree

All the VW "aux battery isolation relay" does is to connect the two batteries in parallel, regardless of any extremes of individual state.

On top of this you have 'Bluemotion' where huge alternator demands are made when braking and consequent higher voltages are applied to the paralleled batteries, and where the BCM actively allows the batteries to drain to 80% when not braking.

Crucially, all the singular BCM has to go on when it starts a charge cycle is the resulting voltage from this mismatched but paralleled pair, and its estimate of the starter-battery state-of-charge from the current monitor. It has no means of judging the state-of-charge of the paralleled leisure battery. With all this in mind you can see how one BCM and a split-charge relay cannot possibly 'optimally charge' both your starter and leisure batteries!

Cheers
Phil

Sounds a bit complicated for me Phil.....(I'm not that clued up on things like this).......all I know is when I'm camping for a few days , with fridge on and lights.....
battery is all good again after a run .....aux 12.9v . that is all I wanted and Vw seem to have done it.
Jerbacampervans.co.uk. seem to agree too.
Maybe it just works in my situation, but I'm glad it does. Cheers.