The perfect lithium LiFePO4 under-seat battery for motorhomes and vans
Find out which lithium battery fits best under the passenger seat of your motorhome or van such as a Fiat Ducato, Citroen Jumper or Peugeot Boxer.
Are you looking for the right battery to install under the seat of your motorhome or camper van? The old lead-acid battery has given up the ghost or is simply no longer sufficient for watching TV and drinking coffee in the morning?
In the following article, we look at what is required and what you need to pay attention to if you want to upgrade your motorhome or van such as a Fiat Ducato, Citroen Jumper or Peugeot Boxer with one or even two lithium batteries.
What battery dimensions for panel vans?
To ensure that the LiFePO4 batteries fit under the passenger seat of a Fiat Ducato, Citroen Jumper or Peugeot Boxer, they must not be higher than 19 cm. Many suppliers of lithium batteries have opted for non-standardized special dimensions, making the decision before purchase unnecessarily difficult.
The magic words for the right batteries are:“DIN standard dimensions“. In a DIN battery, the battery terminals are surrounded by the housing cover and have caps. DIN batteries are usually installed in European vehicles. This type of battery housing always has the standard DIN cone terminals and a base strip for fastening. Just as you would expect from a car battery:
Batteries with DIN standards H7 (318 x 175 x 190 mm) and H8 (355 x 175 x 190 mm) are suitable for Fiat Ducato, Citroen Jumper or Peugeot Boxer.
For Ford Nugget, or VW T5 or T6 fit the smaller H7 batteries (318 x 175 x 190mm).
If you wish, you are welcome to take a look at our offer:
The advantage of these dimensions is that it can even be upgraded at a later date. If a 100Ah or 150Ah lithium LiFePO4 battery is no longer sufficient, a second one can be fitted directly next to the old battery under the seat to provide 200Ah or 300Ah lithium power. Please only connect batteries of the same type!
At this point it is worth mentioning that, unlike lead batteries, lithium batteries can be discharged to almost 100%. Lead batteries only release 50% of their available capacity. In other words, only 50Ah of a 100Ah lead battery can be used.
By installing two 150Ah lithium batteries under the Ducato seat, we would then have the mathematical equivalent of 600Ah lead batteries on board. And that with a light 19KG per battery.
Installation of 2 batteries under the driver's seat
The installation of two 100AH or 150Ah LifePO4 batteries under the driver’s seat is possible in the following chassis:
- Fiat Ducato
- Citroen Jumper
- Peugeot Boxer
Furthermore, in most motorhomes with under-seat batteries, as well as all panel van motorhomes based on the above-mentioned chassis, such as Robeta, Pössl, Vantourer, Kahmann or Knaus. If in doubt, ask your dealer or consult the manual for your van. If a 100Ah / 96Ah lead-acid on-board battery is fitted as standard, you can be 99.9% sure that “large” batteries with H8 standard dimensions will fit.
Ford Nugget and VW T5 or T6 are usually fitted with 80Ah lead batteries. The batteries with h/ standard fit here.
Below is a comprehensive video that explains everything you need to know and shows how to remove the seat and replace the batteries:
Also note when connecting in parallel:
It should be switched “crosswise”. As shown in the picture. There are always slight losses at the cable lugs, which in long-term use would result in the rear battery being charged a little less and consequently ageing more quickly.
Parallel connection of two lithium batteries
When installing two batteries at a later date, make sure that the batteries are connected in parallel as shown here in order to benefit from double the 200Ah capacity.
Please note that only batteries with the same charge status are connected.
This prevents an excessive voltage gradient when connecting the batteries, which could damage the BMS.
Therefore:
a) Therefore, fully charge the batteries beforehand to bring them to the same charge level (full).
or:
b) Check the voltage in the app beforehand to rule out excessive voltage differences between the batteries.
Parallel connection of two lithium batteries
When installing two batteries at a later date, make sure that the batteries are connected in parallel as shown here in order to benefit from double the 200Ah capacity.
Please note that only batteries with the same charge status are connected.
This prevents an excessive voltage gradient when connecting the batteries, which could damage the BMS.
Therefore:
a) Therefore, fully charge the batteries beforehand to bring them to the same charge level (full).
or:
b) Check the voltage in the app beforehand to rule out excessive voltage differences between the batteries.
Also note when connecting in parallel:
It should be switched “crosswise”. As shown in the picture. There are always slight losses at the cable lugs, which in long-term use would result in the rear battery being charged a little less and consequently ageing more quickly.
Charging booster and charger
Wait, don't I need an extra charge controller, charge booster or special lithium charging technology to be able to install lithium batteries in my home?
The old lead charger with CCCV charging characteristics can simply be used to charge a lithium battery. The charging characteristics of LiFePO4 batteries are almost identical to those of lead/gel batteries. It is important to ensure that the charger has deactivated the sulphation function and that the charging voltage is between 14.2V and 14.6V. A BMS (Battery Management System) is usually installed to protect the batteries, as is the case with our batteries. In the case of motorhomes or vans, most of the devices used have an adjustable lead-gel curve. This should be set if available and is ideal with a charging voltage of 14.4V.
Unfortunately, I have to say something about the part with the charging booster:
“It depends.”
The charging booster is required to ensure that the alternator fully charges the on-board battery as well as the starter battery. And only if you have a EURO6 or younger vehicle.
So if you have a EURO6 vehicle and also want the on-board battery to be charged while driving, then yes. Then it is advisable to install a charging booster.
Euro 6 vehicles generally only charge the on-board battery until the starter battery is full. The alternators in older vehicles, on the other hand, continue to generate energy even when the starter battery is full.
However, this varies depending on the manufacturer and vehicle and must be checked on a case-by-case basis.
How do I find out if my battery is charging while driving?
The easiest way to find out whether a charging booster is needed or not is to check the capacity of the on-board battery before and after the journey. This is very simple with our app.
So if I need a charging booster, which one should I choose?
Our batteries can be charged with up to 100A. We recommend the devices from Votronic, which can be found here*:
Votronic 4250683615756 Converter VCC 1212-30 Charge booster B2B*
*Affiliate links. As an Amazon partner, we earn a commission from Amazon on qualified sales
In principle, every Votronic charging booster works. The amperage indicates the current strength, or more simply, how “quickly” the battery is charged.
At 0% battery capacity, a 20A charge booster needs 5h, a 30A charge booster 3h, a 50Ah charge booster 2h, until a 100Ah battery is full again.
For most cases, the 30A charging booster is perfectly adequate.
Conclusion
As you can see, it’s not that complicated with lithium batteries.
- With DIN H7 and H8 installation dimensions, up to two batteries also fit under the seat of your motorhome or van.
- Thanks to the identical charging curve as lead batteries and built-in battery protection via BMS, no additional technology is required. The old lead-acid battery can simply be replaced with the new LiFePO4 battery. If your chargers do not have a LiFePO4 curve, it is best to convert the existing chargers to lead-gel.
- If you also want to charge the battery while driving in your EURO 6 vehicle or newer, then a charge controller / charge booster is recommended.
However, we always recommend going to a trusted workshop and having them carry out the installation.
If you are interested in LiFePO4 lithium batteries, please take a look at our offers.
Supervolt® 12V 100Ah Lithium LiFePO4 battery
For motorhomes, vans, boats, allotments or as energy storage for photovoltaics
€
729
incl. VAT.
-
Incl. Smart BMS and Bluetooth
-
H7 DIN standard dimensions 318x175x187 mm
-
5 year guarantee
-
3000+ cycles
-
Plug and play - directly interchangeable with AGM or lead
Supervolt® 12V 150Ah Lithium LiFePO4 battery
For motorhomes, vans, boats, allotments or as energy storage for photovoltaics
€
1090
incl. VAT.
-
Incl. Smart BMS and Bluetooth
-
H8 DIN standard dimensions 355x175x187 mm
-
5 year guarantee
-
3000+ cycles
-
Plug and play - directly interchangeable with AGM or lead
Also available as a set of two for parallel operation.
At a special price!
Supervolt® 12V 200Ah 2x100Ah Lithium LiFePO4 batteries
€
1390
VAT included.
-
Double reliability, as one BMS is installed per battery
-
Double power output possible - Constant 4KW discharge
Supervolt® 12V 300Ah 2x150Ah Lithium LiFePO4 batteries
€
2090
VAT included.
-
Double reliability, as one BMS is installed per battery
-
Double power output possible - Constant 4KW discharge
