Camping battery setup - change from default setup

JanThorben

New Member
Hi everyone 👋


We have a VW T6 Transporter, 2016 (75 kW TDI, CXGB engine), and want to convert it for light camping use – nothing fancy, mainly:
  • some LED lighting in the back
  • charging for laptop and phones
  • possibly a diesel air heater later

The van came with a factory dual battery setup (starter in the engine bay, AGM 75Ah Varta under the driver's seat, split-charge relay, factory cable 7H0 915 531 routed underneath the vehicle). The rear AGM is probably end-of-life after ~10 years – on our last cold-weather trip the factory water heater ran a few times overnight, and in the morning the van wouldn't start.


Trying to figure out the best path forward:
  1. Just replace the AGM 1:1 (~200 €) – factory system untouched
  2. Replace AGM + add proper consumer side (fuse panel, USB-C PD, LEDs) – camping loads on the seat battery
  3. Replace AGM under seat directly with LiFePO4 100Ah + DC-DC charger instead of split-charge relay – would need to adapt the factory energy management
  4. Add Lithium 100Ah as third battery in the back with DC-DC charger (Votronic 1212-30 or Victron Orion XS) – factory system left completely alone

Questions:


  • Has anyone replaced the factory AGM under the seat with Lithium on a T6? How did you deal with the battery sensor / pyrofuse and coding?
  • If Lithium goes directly under the seat: does the VW energy management get confused, or can it be coded properly?
  • Or better to add a third battery in the back, factory system untouched? How did you route the charge cable?
  • Which battery does the factory water heater typically draw from on a T6 – starter or second battery?
  • For an AGM 1:1 swap: does it need to be coded, or is it fine without?
  • Split-charge relay after 10 years – how do you check if it's stuck closed?

I'm reasonably handy and would do the consumer side myself, but anything touching the factory system I'd rather take to a shop.


Thanks for any tips or experiences! 🙏
 
Definitely replaced that old AGM for a 100ah and they DC,-dc charger.

If you have the factory split charge relay then you have all the cables you need to get it up and running.. I done the same thing on my 2018 T6 with factory leisure battery.





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More info over here:

 

  • Has anyone replaced the factory AGM under the seat with Lithium on a T6? How did you deal with the battery sensor / pyrofuse and coding? ... ---- There is no sensor on the leisure battery, and you can replace the fuse is with whatever you need.


  • If Lithium goes directly under the seat: does the VW energy management get confused, or can it be coded properly?..---- . Nothing to worry about as they found will be already coded to assume a second battery... Only the California has more advanced battery management set up with three batteries but nothing to worry about on a standard T6 with one battery

  • Or better to add a third battery in the back, factory system untouched? How did you route the charge cable? --- no just upgrade the AGM and a driver's seat that will give you twice the run time as your standard AGM battery.


  • Which battery does the factory water heater typically draw from on a T6 – starter or second battery?.. &-- I'm not sure comma is it an engine preheater?

  • For an AGM 1:1 swap: does it need to be coded, or is it fine without?.. the starter battery will need to be coded back in but not the auxiliary battery.

  • Split-charge relay after 10 years – how do you check if it's stuck closed? &-- use a multimeter on volt DC so monitor the battery rest in voltage and then start the engine turn the lights on or go for a drive to see if the voltage starts going up for example to 13.6v
 
Agree, if you already have a factory leisure you’re in a really good position to just replace that and the relay with a lithium battery and DC-DC charger. All the cables you need are already there under the seat - including the engine run cable that triggers the relay which can be hooked directly into the new DC-DC to tell it when to operate.
 
Agree, if you already have a factory leisure you’re in a really good position to just replace that and the relay with a lithium battery and DC-DC charger. All the cables you need are already there under the seat - including the engine run cable that triggers the relay which can be hooked directly into the new DC-DC to tell it when to operate.
You can even leave the factory split charge relay in place and put the B2B in series with the relay and battery.
 
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