Upgrading the Under Seat Leisure Battery to Lithium and Removing the 2nd Leisure Battery

[andrew_kombilife]

Hi All,

I have a T6.1 California OCEAN and I am looking to upgrade the Leisure Battery System to Lithium from the AGM Batteries that are in the vehicle.

I can get far more useable capacity with just one Lithium Battery under the Left Hand Front Seat, so I am thinking of just upgrading the battery under the Left Hand Front Seat and am wondering if anyone has done a similar thing in the past?

To be honest my biggest concern is actually deleting the Second Leisure Battery which is installed in the Rear Cabinet. From what I understand the two Leisure Batteries are connected in parallel, however I am not sure exactly where the cable from the Rear Leisure Cable connects to the Leisure Battery under the Front Left Seat? I assume that it connects somewhere to Fusebox SH, however can anybody help me out here with identifying exactly where this connection is made?

Also, are there any ramifications that I should be aware of removing the Second Leisure Battery?

Thanks in advance!

Andrew

 

[WelshGas]

Hi All,

I have a T6.1 California OCEAN and I am looking to upgrade the Leisure Battery System to Lithium from the AGM Batteries that are in the vehicle.

I can get far more useable capacity with just one Lithium Battery under the Left Hand Front Seat, so I am thinking of just upgrading the battery under the Left Hand Front Seat and am wondering if anyone has done a similar thing in the past?

To be honest my biggest concern is actually deleting the Second Leisure Battery which is installed in the Rear Cabinet. From what I understand the two Leisure Batteries are connected in parallel, however I am not sure exactly where the cable from the Rear Leisure Cable connects to the Leisure Battery under the Front Left Seat? I assume that it connects somewhere to Fusebox SH, however can anybody help me out here with identifying exactly where this connection is made?

Also, are there any ramifications that I should be aware of removing the Second Leisure Battery?

Thanks in advance!

Andrew

On the T6.1 both Leisure batteries are monitored by the Control panel, so it may throw a hissy fit if it only sees one. The Mains battery charger may or may not be compatible with a Lithium battery.

If you follow the connections to the +tve pole on the front Leisure battery you should find a large red lead which comes from the rear battery. The earth's from both batteries are connected to a local chassis earth.

 

[yorkshiredave]

I believe the leisure battery under the passenger seat is dedicated to run the Auxiliary Diesel Heater and the Leisure Battery under the rear wardrobe runs the fridge, sockets and lighting, etc. in the rear habitation space of the vehicle, both managed by the charge control unit under the wardrobe/fridge (which also trickle charges the vehicle starter battery) and displayed via the main Control Panel. So deleting one of the batteries and running from a single Lithium battery would require some wiring changes to ensure the auxiliary heater and habitation circuits are correctly powered. Personally, if I was thinking about doing this I would retain two Leisure batteries but just change to smaller balanced (same capacity) Lithium to save messing with wiring. Though are there any considerations of using different Ah capacity batteries to the original, as will the Battery Charging Unit/Inverter not be calibrated in some way to battery capacity? I’m sure many people have done this before on this forum who can give you the low down.

 

[WelshGas]

I believe the leisure battery under the passenger seat is dedicated to run the Auxiliary Diesel Heater and the Leisure Battery under the rear wardrobe runs the fridge, sockets and lighting, etc. in the rear habitation space of the vehicle, both managed by the charge control unit under the wardrobe/fridge (which also trickle charges the vehicle starter battery) and displayed via the main Control Panel. So deleting one of the batteries and running from a single Lithium battery would require some wiring changes to ensure the auxiliary heater and habitation circuits are correctly powered. Personally, if I was thinking about doing this I would retain two Leisure batteries but just change to smaller balanced (same capacity) Lithium to save messing with wiring. Though are there any considerations of using different Ah capacity batteries to the original, as will the Battery Charging Unit/Inverter not be calibrated in some way to battery capacity? I’m sure many people have done this before on this forum who can give you the low down.

I'm afraid you are incorrect in your assumption.
The rear leisure battery is wired in parallel to the under seat battery to create a 150 amp battery. The only additional connection to the rear battery is the battery monitor module on the T6.1.

All the leisure electrics are connected to the under seat battery via a +tve bus bar and fusebox.

 

[yorkshiredave]

I stand corrected! Would this have been the same in our T5.1 Cali, as I could have sworn the under seat battery was dedicated to the heater??


Sent from my iPhone using Tapatalk

 

[WelshGas]

I stand corrected! Would this have been the same in our T5.1 Cali, as I could have sworn the under seat battery was dedicated to the heater??


Sent from my iPhone using Tapatalk

Yes, T5/5.1/T6 and T6.1
The Parking Heater, Fridge, rear habitation lights, water pump , inverter and rear 12v sockets are all wired to the Leisure battery under the front passenger seat.

 

[andrew_kombilife]

On the T6.1 both Leisure batteries are monitored by the Control panel, so it may throw a hissy fit if it only sees one. The Mains battery charger may or may not be compatible with a Lithium battery.

If you follow the connections to the +tve pole on the front Leisure battery you should find a large red lead which comes from the rear battery. The earth's from both batteries are connected to a local chassis earth.

Thankyou and great comments, where is the Mains battery charger actually located? Additionally, I am wondering if anyone has a photo of the large red cable coming from the front leisure battery +ve pole?

 

[WelshGas]

Thankyou and great comments, where is the Mains battery charger actually located? Additionally, I am wondering if anyone has a photo of the large red cable coming from the front leisure battery +ve pole?

Mains charger is located above the rear leisure battery.

 

[arcadelt]

Can you just change AGM to lithium? I thought there were dangers for the alternator that requires some additional protection hardware to be put into place?

 

[Quiddle]

Here's a Youtube video on changing lead acid batteries to LiFePo on a boat and the problems involved. It can certainly be done but involves a lot more than just a bit or rewiring.

 

[kave]

When my sinlge AGM battery where starting to wear out (we have a beach) I decided against LifePo batteries as a replacement. To me its not plug and play yet, and the price is too high for batteries that are more ”complete”.
LifePo batteries can’t be charged when too cold, they require a different charge profile.
As I see it to make it optimal, you need to replace all kind of charging of the battery, the 230V charger, how the alternator charges, how solar charges. Pair this in with all the above might charge your AGM engine battery.
Further, these batteries should not be charged to 100% all the time.
Someday, when the prices goes down, I will go LifePo (or whatever is latest and greatest) for now now it’s not worth it for me. I get more solar panels instead.

 

[SanderR72]

I changed both my AGM’s in my Ocean to LifePo4 from SuperVolt (the Polar version that charges below zero degrees as it has its own heating).

As a drop-in replacement.

No other wires, no DC-DC charger, just the existing split relay.

I do have to say I never use EHU, so my LifePo4 leisure batteries are only being charged while on the move with the existing alternator.

They were installed in February of this year. So far so good without any problems. Fingers crossed.

 

[Christine Kirk]

Why do it?
Our nearly 6 year old T6 batteries are still working just fine , so why do they need changing? Lithium batteries are prone to combustion aren’t they?

 

[CaliDeventerNL]

Hello, not shure what the gains would be in removing the rear battery. The space in almost unusable.
Perhaps consider an alternative:We have bought and have installed (not ourselves) two small 100 amp lithium. The package was VW approved and warranty remains intact. The new setup was even added to the vehicle configuration in the VW database.
We have now 200 amp usable lithium which last for a few days without external power. Driving for two hours charging the batteries completely because we added also a 70 amp battery charger.
We are using this now for two years and it works flawless. Battery is nicely indicated in panel and the app which comes with the battery

 

[Kjetil]

On the T6.1 both Leisure batteries are monitored by the Control panel, so it may throw a hissy fit if it only sees one. The Mains battery charger may or may not be compatible with a Lithium battery.

If you follow the connections to the +tve pole on the front Leisure battery you should find a large red lead which comes from the rear battery. The earth's from both batteries are connected to a local chassis earth.

Hi WelshGas.
This is maybe out of scope. I was hoping this thread would give me the answer where the rear battery connects. I want a rear battery since I don’t have one. I would like to connect my solar panels.
But according to your comment you are saying it connects under the front seat. Right? And not, for instance, under the fridge?