Installation report: 150 Ah lithium battery in the VW T6.1 California Beach
Installation report of a Supervolt 150 Ah LiFePO4 battery in the VW T6.1 California Beach (model year 2020), which was provided to us by our customer.
Guest article: Replacing AGM with 150 Ah LiFePO4 battery in VW T6.1 California Beach
Our customer sent us a field report on the installation of our 150 Ah Supervolt LiFePO4 battery in his VW T6.1 California Beach Camper. In this article, he explains the details of the installation, the advantages of the new power supply and what to look out for when converting.
Table of contents
Initial situation
The originally installed 75 Ah AGM battery, which is now four years old, has suffered considerable loss of capacity. As a result, it was discharged after a single night with the parking heater
and a rainy day did not provide enough solar energy to ensure another warm night. An upgrade was therefore required and rather than re-fit an AGM battery, I opted for a more comprehensive upgrade.
So that we can also charge our e-bikes in the future, it should be a correspondingly large battery. Here I came across the article that the 150 Ah Supervolt LiFePO4 battery from Supervolt can easily fit under the driver’s seat of the T6.1. The 150 Ah is just about enough, because an e-bike battery has 700/800 Wh, which means that approx. 54/62 Ah are required for a full charge (the 700 Wh battery drew 42 Ah from “empty” to full).
The original built-in inverter can be used for this (max. 500 watts of power can be called up), which appears to work very efficiently.
The Supervolt battery arrived very quickly and was superbly packaged, the communication was also very
good, so I can only recommend the store.
Note:
With the introduction of our new battery series at the beginning of October 2025, the SE series models no longer have RJ45 interfaces to external devices (e.g. Victron, Truma iNet, etc.), as these are not required by all users.
Due to the elimination of these interfaces, we can no longer offer the SE seriesat a lower price with immediate effect.
The PRO series however, still has the corresponding interfaces.
>> Discover our LiFePO4 SE batteries directly in the online store <<
Installation process and customizations
The seat must be removed and the starter battery disconnected for the conversion. The entire
seat console should be removed so that you can work cleanly. In the end, it is faster and better, so I can only recommend everyone to take on the little extra effort.
Accordingly, loosen all fuse holders and unscrew the frame at the four corners and remove the handbrake from the seat frame. To do this, pull the trim panel forwards and loosen two
screws.
I have drilled out the welded points so that the sheet metal can be machined individually.
The sides on the right and left have to be cut off so that the wider battery fits. The very thin sheet metal on the side of the frame needs to be slightly removed in the lower area.
A little paint on the bare sheet metal and 4 rivet nuts in the frame (for the later strut to which the MPPT and DCDC converter will be attached) and everything could be reassembled
.
Thanks to the standardized H8 housing, the Supervolt battery fits perfectly into the existing (machined) holder. Only the indentations on the battery had to be machined slightly so that they fit neatly into the sheet metal. As a result, the battery sits perfectly in the holder, tightened at the front and rear.
The height is the same as the old battery and the connections also fit, making it look more or less original.
And bang, the capacity has increased by a factor of 2-4 (depending on the calculation, because a LiFePO4 should be kept between 20-80 % if possible and an AGM should not be discharged below 40 % if possible
).
As the new generation has an on/off switch, I also wanted to integrate this neatly
. Unfortunately, this is supplied already soldered on, which means that the solder connection must first be removed and then soldered on again for a clean installation in a
hole. There is potential for improvement here.
Supervolt note: With the next generation of on/off switches, the button can be detached so that it can be easily mounted on a wall.
The switch only prevents the battery from being charged or heavily discharged. When switched off, a voltage of 550mV is applied to the terminals, which causes the original LED lighting to go on and off. I had hoped that the battery could be switched off completely.
Supervolt’s note: This has already been improved with the new BMS V7. The switch now allows the BMS to be completely disconnected from the power supply. This affects all batteries from year of manufacture 2024.12.
Due to the new LiFePO4 with a different charging characteristic than the original AGM starter and body battery, the original cut-off relay must be removed, as this only short-circuits the starter and body battery, which leads to a less than optimal charging voltage. In addition, too high a current would flow with an empty
LiFePO4. An AGM automatically limits this due to the significantly higher internal resistance, but a LiFePO4 does not.
I have installed a DCDC converter instead of a cut-off relay. The 150 Ah should be charged with a maximum of 50 A.
There is also an MPPT solar controller for solar feed-in.
I used a square groove profile for fastening and was thus able to carry out a clean installation with good ventilation.
A fuse box from Offgrid is connected to the load output of the MPPT controller so that I have the option of connecting additional consumers easily and fused under the seat.
The calculator on the Supervolt page helps you to determine the correct cable cross-section.
The original 25 mm2 cables are problematic; I used pin cable lugs for the 25 mm2 on the DCDC converter. These had to be ground down slightly so that they fit properly.
Provided you have the appropriate cable shears and press.
The MPPT controller only allows a maximum of 10 mm2, which is sufficient due to the short distances, but should be taken into consideration during installation. The thick cables make installation difficult and it is very fiddly, but with patience and care everything is feasible.
The fuse box is simply clamped under the seat for easy access. Everything else is firmly bolted down
. However, there is now no more space under the driver’s seat. The installed components and the 150 Ah battery from Supervolt will hopefully accompany me for the next year(s).
Conclusion on installation and initial experience
The system has now been in operation for over a month and is running perfectly. I have set the absorption voltage of the MPPT controller to 13.25 V, whichcharges the battery to 70-75%. This is sufficient for normal operation and only when we really want to chargethe batteries of the e-bikes do I charge to 100 %.
I am assuming approx. 20-50 cycles per year, which would mean that the battery would last 60 years. I
am curious and will be happy to report back.
The AGM lasted just 4 years with the constant cycles caused by the VW charging management.charging management.
I also adjusted the battery type and capacity for the body battery via VCDS, now the controller shows twice the time, but also adjusts itself again and again – in other words, this is still not a reliable
indicator of how long the battery will last, but there is the Supervolt app for this. The Bluetooth connection to the battery is very stable and the range is excellent, as is the
information that is provided.
I have not yet observed the VW Controller switching off the heating or connected consumers. In this case, the VW controller seems to be partly based on the power drawn and supplied with regard to the remaining usage time, but also on the voltage, which leads to the described adjustment. I have not made any further adjustments to the internal controller apart from updating the values via VCDS, but we have also not installed an original shore power connection.
👉 You can access our LiFePO4 SE batteries in the online store here
Important note
This is an installation report from a customer, which he has shared with us to the best of his knowledge and belief. The installation methods, experiences and tips shown are based on his personal implementation and assessment.
Please note: We assume no liability for the accuracy, completeness or safety of the information.
Please always observe the applicable regulations and manufacturer’s specifications for your vehicle and the components installed.
Acknowledgments
We would like to take this opportunity to thank our customer for the very well-described report! We hope that the publication of these instructions will help you to replace AGM batteries with our lithium batteries in the VW T6.1 California Beach Camper.
With the new battery, nothing stands in the way of your next vacation. We wish you a safe journey and unforgettable trips.
If you are also planning to convert your vehicle yourself, please write to us ([email protected]). We will be happy to give you a discount on the purchase of your battery for a report.
Supervolt LiFePO4 batteries and accessories
In our store you will find our complete selection of LiFePO4 batteries – ideal for motorhomes, boats or solar systems. Thanks to their versatility, our batteries can be used reliably in almost any area.
Of course, you can also find the right installation accessories such as solar controllers, charging boosters or inverters directly from us – for a perfectly coordinated system from a single source.
