No continuity between main battery +ve and OEM split charge relay. Could it be this cable?

[matt_ew]

Got an ex RAC van with all their cabling cut out. All the split charge wiring seems to be in place fine, with working fuses and relay (continuity all checked with engine on and off). Looked at the main battery and saw this cable wasn’t attached to anything though. Failing this I’ll assume it’s the big fuse under the main battery that’s blown?

 

[TallPaul_S]

That looks very aftermarket - not factory at all. I'd assume that's the feed for some of the RAC gubbins.

The factory 2nd battery wiring goes from the hidden fuse box under the battery with a 100a fuse to the passenger seat base into the 80a fuse and relay.

 

[matt_ew]

oh I just meant the aux battery was OEM. I’m not surprised the main cabling isn’t! I’ll check the fuse under the battery then thanks

 

[TallPaul_S]

oh I just meant the aux battery was OEM. I’m not surprised the main cabling isn’t! I’ll check the fuse under the battery then thanks

If you've checked the 80a (presuming T6, not 6.1) and you're not getting around 14v at the aux battery with the engine on and lights on, then yeah the next place to check is the 100a in the e-box

While you're there, make sure that nothing is attached to the starter battery negative before the shunt - or the system won't be able to read the battery level correctly.

 

[matt_ew]

How do you mean sorry? Surely I’m taking the battery out to get there and therefore nothing will be connected?

 

[TallPaul_S]

How do you mean sorry? Surely I’m taking the battery out to get there and therefore nothing will be connected?

I just mean with the extra wiring that's been added - it's probably all been disconnected already but it might have an extra connection that's been added to the negative post. If there's now only the std factory connections then you're all good.

 

[roadtripper]

Hopefully you found this which might be of some help?

RAC Van Wiring Diagram

RAC van wiring diagram kindly supplied by Bri-Stor Systems who fit them out for the RAC This diagram show fusebox layouts and wiring schematics for all the additional systems

www.t6forum.com

 

[roadtripper]

I suspect from the look of the cables and (I assume) meaty fuses that's the tap from the starter/alternator for the two jump socket points and also the motors for the deployable trailer (RDT on the diagram)

If so they are _probably_ redundant for your use but consider if they could be repurposed for charging while the van is sat on a drive.

If your van is wired the same as the diagram your AUX battery feed should be factory wiring so it isn't shown on the RAC diagram as that's additional wiring. So you should have a 100A in the e-box under the starter battery and an 80A on the aux battery.

 

[matt_ew]

Was the fuse under the battery that was the problem! Any idea how this could've happened? Appreciate it could be anything but more so I can avoid blowing it again when I install the aux battery.

 

[roadtripper]

Could well have happened while the RAC equipment was being removed. In most cases you'd expect the 80A one to go first, it's part of the reason it's there so you don't have to remove the battery, but if they accidentally shorted the charge relay to ground or left the wrong cable off it and it touched the body...

Just when installing be very careful not to do the same.

 

[matt_ew]

Brilliant thanks, figured it was probably shorted like that at some point. Found the 80a fuse was also blown but had been swapped with the 40 lmao

 

[smithson15]

Hi mate,
Trying to sort out the wiring for my ex rac one I got a few days ago. I can’t see a feed to charge the aux battery and I don’t have a split charger? Do you have any pics so I can see what should’ve been here?

Cheers

 

[matt_ew]

Hi mate,
Trying to sort out the wiring for my ex rac one I got a few days ago. I can’t see a feed to charge the aux battery and I don’t have a split charger? Do you have any pics so I can see what should’ve been here?

Cheers

Hmm, there's no wiring at all under the seats? My problem ended up being a blown fuse under the main battery. Never needed to touch the relay circuits in the end!

 

[roadtripper]

Hi mate,
Trying to sort out the wiring for my ex rac one I got a few days ago. I can’t see a feed to charge the aux battery and I don’t have a split charger? Do you have any pics so I can see what should’ve been here?

Cheers

The "split charger" isn't realy - it's just a high current relay in the fusebox under the seat with the aux battery - post a pic of what you have and folks should be able to help

 

[smithson15]

The "split charger" isn't realy - it's just a high current relay in the fusebox under the seat with the aux battery - post a pic of what you have and folks should be able to help

Thanks mate, I found that after reading on here. Away for work now but will have a look when I’m home. Couldn’t find a feed after I removed the RAC cable from the main battery, but presumably it’s one of the smaller red ones coming from the alternator(?)

Cheers

 

[roadtripper]

Thanks mate, I found that after reading on here. Away for work now but will have a look when I’m home. Couldn’t find a feed after I removed the RAC cable from the main battery, but presumably it’s one of the smaller red ones coming from the alternator(?)

Cheers

If it's OE it will be out of the monster fuses under the starter battery - 100A in the engine bay and then feeding an 80A under the seat.

 

[smithson15]

Ok, nice one. I disconnected them fuses from the main battery because it was in copex and was clearly RAC after market install but maybe I missed something.

This is what's confusing me, if the removing the RAC feed was the only feed to the aux battery, then the aux battery must have been fitted by RAC, but it looks like its feeding some OEM VW looming.

There has to be another OEM feed.

Need to have a better look, annoying being away I want to go through it now!

 

[roadtripper]

The big stuff and fuses in copex from the starter will be the feeds to the jump start sockets and the RDT (folding trailer) that are to the right of the RAC diagram I suspect.

The OE feed you won't really see unless you remove the starter battery as it goes out underneath and then through the firewall.

 

[smithson15]

Yeah, ok, good man. It was basically one that fed the stuff in the back then I presumed one did what you just said for the jump start.

I just want to make sure it still charges basically and then leave it all alone and put my own install in.

 

[roadtripper]

Keep in mind the only thing it's doing in an OE install if you've removed the RAC fuseboxes is feeding 1 maybe 2 12v sockets. If you are putting a leisure install in it makes sense to use it and save some space, or at least use the decent wiring and ignition signal to the charge relay to put in a decent DC-DC charger and a LiFePo battery instead.