Tge oem split charge

[K13rmj]

Hi all Recently received a 2019 man tge works van for on site fitting ect
The van came with a sterling power charger wired into the battery under the passenger floor, I believe this is draining the battery as when went out to start it after a few days the battery was flat,
After doing a bit of research iv found out that this van has a main and an aux battery under the bonnet and is linked via a relay behind the engine bay battery (aux), has anyone successfully used this as a leasure battery to the extent where if the aux battery discharges the main battery under the floor will still start the van then charge the aux battery via the oem relay both battery’s are vw agm
Thanks

 

[rod_vw]

I don't know how the van was accessed and perhaps used during those few days but you will find that the TGE/Crafter has a considerable drain on the engine battery just by unlocking it and opening the door. You will find that just with a week of pottering in and out without starting will drain a lot off the engine battery.

The Stirling Power unit should be capable of charging the second battery correctly but I suspect that the battery capacity is rather small for use as a camper leisure battery.

 

[Jaywesty]

After calling man tech a few days bk on the phone ,he mentioned nothing should be connected to the starter battery if you have the auxiliary battery under the bonnet it should go to that battery.
Because the 2nd battery has a cut off that if it’s drained it won’t drain the starter battery??
My Clayton is connected to the 1st starter battery so it looks like I need to move the connectors to the auxiliary battery under the bonnet??
Not sure if this guy is correct?
But it’s a right faff to move the power cables now an extra 4ft or so ,if anybody knows better please let me know

 

[Lebowski]

Why do you think the MAN service advisor is wrong?

You must always read the upfitters manual before you change anything to your vehicle.

Find it here: Alloy wheels and tyres

 

[Jaywesty]

Why do you think the MAN service advisor is wrong?

You must always read the upfitters manual before you change anything to your vehicle.

Find it here: Alloy wheels and tyres

I don’t think he is wrong at all but from gauging our conversation it’s a bit like he was stabbing in the dark and from explaining the issue with the pump under the bonnet running I hate to say that the answers he gave me didn’t make sense.

 

[Jaywesty]

Also the tracker fitter who is very clued up and the Clayton tech who is a fully trained technician also says it’s fine so I’m not sure anymore tbh

 

[rod_vw]

Well I guess from a manufacturer's point of view he is correct as a vehicle having a factory fitted second battery was designed to have that power source supplying power to all auxiliary items. He's also correct in saying that the second battery under the bonnet is isolated from the main battery when he alternator is not generating power so it cannot drain the starter battery come what may when the engine is not running.

However 99% of us don't have a factory fitted second battery so we connect to the +ve pole of the engine battery via a fuse to feed whatever version of battery to battery equipment we choose and onwards to our leisure battery. If that equipment is correctly wired and configured there should be no drain on the engine battery when the alternator is not generating power.

My first test of the leisure connection B2B would be to disconnect the +ve connection from the starter battery (i.e. remove the fuse) then replicate the opening and closing of the van as best I could to see what happened.