Drop-in LiFePO4 battery replacement in the Affinity campervan: a field report
Field report on the installation of 180Ah POLAR LiFePO4 battery in the Affinity Van based on the Peugeot Boxer, which was provided to us by our customer.
Guest article: Replacing a defective LiFePO4 battery from another manufacturer with a SUPERVOLT lithium battery while on vacation
Imagine you’re in the middle of a well-deserved vacation – and suddenly the battery in your van goes on strike. That’s exactly what happened to our customer: With his Affinity van based on the Peugeot Boxer (built in 2021, first registered in June 2022), he was faced with an unexpected problem. But instead of canceling his vacation, he decided on a quick solution and replaced the faulty battery from another manufacturer with our Supervolt LiFePO4 battery and was able to continue his trip without any further interruptions. In his experience report, he tells us how the replacement went and what advantages the new battery brought him during his vacation.
“Replacing the battery has paid off in every respect. The new Supervolt Polar LiFePO₄ 180 Ah provides reliable power – even at night or in bad weather. The lights, fridge and fan are stable again, the display in the battery computer is plausible and the feeling of being able to travel self-sufficiently again is priceless.”
Table of contents
The problem
From the second day of my trip, the power supply in the camper failed. Without shore power, the voltage suddenly dropped as soon as consumers such as the fridge or lights were switched on. The battery initially showed a voltage of 13.8 V, but it dropped to below 8 V even with a low load.
The result: darkness in the camper, flickering displays and an on-board computer that could no longer be started. The solar system also reported no yield at all. A power supply was only possible with the engine running.
The self-sufficiency I had planned for was gone – after just a few days.
First diagnostic attempts on the road
All displays initially showed normal values: the battery computer reported 13.7 V at 94 % capacity. However, the behavior under load quickly raised doubts. The voltage collapsed immediately and the refrigerator reported error code 19 (battery below 20 %).
Solar yield: zero. No display. No charge.
I initially ruled out a fault in the consumers – the voltage breakdown directly at the battery was too obvious. All the fuses were also intact.
A technical problem was obvious – but not yet tangible.
Trust lost - no consultation with dealer
According to the display, the battery initially showed normal values, but the voltage immediately collapsed under load. The solar panels did not provide any yield. The situation was not only frustrating, but also puzzling.
Bluetooth access to the battery’s BMS was not possible – despite the corresponding function according to the description. This indicated a defective battery management system (BMS).
Consultation with the manufacturer was deliberately avoided, as direct help would not have been possible on the road. The confidence was also not overly high, as the factory-installed 120 Ah battery in conjunction with a Büttner 1700S inverter turned out to be significantly undersized. Not even a coffee machine worked with this combination.
During a conversation at the trade fair, the dealer recommended switching on the engine to avoid the problem. The second option: a new 150 Ah battery at a price of around CHF 2,500.
It was clear to me that this solution was not viable – technically unconvincing, financially unreasonable.
New battery - new hope
After two weeks of daily searching for a shore power connection, the decision was made: A new battery was needed. After intensive research, the choice fell on the Supervolt Polar LiFePO₄ 180 Ah – a robust lithium battery with integrated heating, RJ45 interface and external on/off switch. The dimensions fitted almost perfectly into the existing battery compartment and the electrical connections corresponded to the previous system. The price was 1429 euros including VAT – and was therefore significantly cheaper than the original dealer’s offer.
The order was placed online during the journey. A pickup parcel store in Flensburg was chosen as the delivery location in order to receive it as quickly as possible.
After almost a week of downtime, the journey could be continued – with the new battery safely in the luggage.
Note:
With the introduction of our new battery series at the beginning of October 2025, the POLAR 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 POLAR series can now be offered at a lower price.
The PRO series however, still has the corresponding interfaces.
>> Discover our LiFePO4 POLAR batteries directly in the online store <<
Installation and special features
The challenge during installation was not so much the length of the new battery as the width: the existing cut-out in the raised floor was so narrow that the old battery could only be removed with difficulty. Apparently, the original battery was installed first and then the cables were inserted, making it practically impossible to pull it out.
The old battery could only be removed and the new one inserted by carefully cutting back around 2 cm at the base opening using an oscillator. This had to be installed rotated as the poles were in a different position.
The electrical connection to the battery computer worked again immediately after installation. The BMS of the old battery had presumably failed completely – there was no longer any display or Bluetooth signal.
The new battery was connected to the supplied manual on/off switch via the RJ45 interface. The switch was relocated to the kitchen cabinet above and enables the battery to be switched off selectively, for example during longer downtimes or maintenance work. The actual main emergency switch for the entire power supply is located in the rear electronics box as usual.
Conclusion and recommendation
Replacing the battery involved a lot of work, but it was worth it in every respect. The new Supervolt Polar LiFePO₄ 180 Ah provides reliable power – even at night or in bad weather. The lights, fridge and fan are stable again, the display in the battery computer is plausible and the feeling of being able to travel self-sufficiently again is priceless.
Although the battery is larger than the original, it could still be installed with a little manual skill – even without a specialist workshop. This project shows that it is possible to replace a battery in a camper van while on the road if you are prepared and keep your nerve.
A reliable power supply is essential, especially for longer trips or everyday life away from the campsite. If, like me, you are dependent on a replacement, the Polar series from Supervolt is a powerful and solid solution – and above all: a battery that delivers what it promises.
👉 You can access our LiFePO4 POLAR batteries in the online store here
Disclaimer
This article is based on an experience report provided to us by a customer to the best of his knowledge and belief. The installation methods, tips and experiences presented reflect his personal approach and assessment.
Important note: We accept no liability for the accuracy, completeness and security of the content.
When carrying out your own conversions, please always observe the applicable regulations and the manufacturer’s specifications for your vehicle and the components installed.
Acknowledgments
We would like to thank our customer for his exciting experience report! During his vacation, he easily replaced his defective LiFePO4 battery from another manufacturer with a Supervolt battery – and was thus able to continue his journey without interruption.
We wish you a safe journey at all times and many unforgettable adventures!
Lithium batteries and accessories
In our store you will find the complete selection of LiFePO4 batteries – ideal for motorhomes, boats or solar systems. Thanks to their versatility, our batteries can be used reliably in a wide variety of applications.
Suitable installation accessories such as solar controller, charging booster or inverters are of course also available directly from us – for a perfectly coordinated system from a single source.
