The battery under the passenger seat

[barrascages]

We have a T6 van which is going to be used for transporting dogs about as we have more dogs then our current caddy can carry

To keep them cool i have fitted a roof fan (thread to follow)

This will be the only extra stuff that is electric that will be fitted to the van so i see no need to go all in with a full electric install

There is an extra battery under the seat which i assume is just for auxiliary power as it has little cables

I intend to run the fan off this.

If this goes flat will the van still start and will it cause any other issues?

 

[roadtripper]

Pictures of the existing setup and more details of the van might help folks advise.

 

[barrascages]

it is a van

no windows no fancy stuff

Just a plain ordinary standard van

 

[roadtripper]

Yes, which generation?

 

[barrascages]

Yes, which generation?

i thought T6 was a generation

So in which case i have no idea

 

[roadtripper]

Apologies trying to assist across 2 parallel threads, you mentioned the generation in one but not the other.

It's a MOLL battery so an OEM part, if one with known failure issues.

Is the battery under the bonnet the same? I see what you mean about the wires they look less OEM - I wonder if a previous owner tried to make use of the original starter MOLL battery when it started to fail.

 

[roadtripper]

As an aside if it's a 4 Motion it's not entirely ordinary, would have very much liked to find a 4 Motion Caravelle

 

[barrascages]

Apologies trying to assist across 2 parallel threads, you mentioned the generation in one but not the other.

It's a MOLL battery so an OEM part, if one with known failure issues.

Is the battery under the bonnet the same? I see what you mean about the wires they look less OEM - I wonder if a previous owner tried to make use of the original starter MOLL battery when it started to fail.

The cables are OEM and go through a fuse so it hasn't been added to make it easier to start

it starts fine

the battery under the bonnet is a VW one

I just want to know if i drain the battery under the seat will it pull down the starter battery as well

 

[roadtripper]

The cables are OEM and go through a fuse so it hasn't been added to make it easier to start

it starts fine

the battery under the bonnet is a VW one

I just want to know if i drain the battery under the seat will it pull down the starter battery as well

Hence why I'm trying to determine when and why it was added and therefore how it is charged.

If it's OEM you should also find a charge relay under the seat somewhere feeding the positive.

So long as that really is correctly pulling in with the engine running and dropping out when it's not it should isolate the second battery when parked.

If you take up VIP Membership you can get access to the wiring diagrams which will show all the circuits fed by it, might be useful for your dashcam questions if you want one with parking mode.

 

[roadtripper]

If you think draining it is likely then that will kill a lead acid pretty quickly, and the MOLL batteries are known to prone to failure.

I'd wire a low voltage cut out into the fan circuit as well to try and keep the battery at about 50pct - set it at 12.0v you should be about on the money.

 

[barrascages]

I'll consider the VIP membership

and there is a relay under the seat which i assume is a charge relay but i don't think it is a split charge or anything fancy

 

[roadtripper]

Split charge is exactly that basic, if it's OEM it will just get a signal from the ECU rather than trying to do voltage monitoring etc.

You should have 2 heavy ish red cables through it and then a black signal wire and a brown earth cable to the earth point.

Should be fed from an 80a fuse 26 in box H

 

[Pete C]

Some more photos of the wiring around the battery will help.

As mentioned above, these type of batteries do not like to be run flat.

Pete