Batteries and storage
LiFePO4 battery for motorhomes.
Under the seat, charge, monitor.
A LiFePO4 battery gives a motorhome more usable energy at lower weight than lead-acid or AGM. For the on-board system and battery to work together, a charger, DC-DC charger, fusing and monitoring are part of the job. philippi supplies BullTron batteries with heating, including in under-seat format, and the matching components from Remseck am Neckar.
Charging down to −30 °C with heating (Polar).
Under-seat up to 750 Ah at 12.8 V.
P-BUS Values straight on the PCU.
Capacity calculator
How big does the battery need to be? Calculated in one minute.
Enter your loads. The calculator shows the capacity you need and the matching BullTron Polar batteries, ready to order.
Your loads
One line per load: current in amps and realistic running time per day.
You need about
– Ah
Nominal capacity of a LiFePO4 battery bank, with 25 % reserve and 80 % depth of discharge.
Suitable batteries
Several batteries: only identical models, connected in parallel as specified in the data sheet.
How it is calculated
Matching products. Battery, charging, fusing.
Use the space under the seat
The BullTron Polar under-seat batteries use the space beneath the driver or passenger seat. They come with 350, 540 and 750 Ah at 12.8 V. The 750 Ah has a metal housing, weighs 56 kg and is delivered by freight carrier. For flat double floors there is the Polar Slim, 58 mm high, in 12 V and 24 V.
Charging while driving
The alternator alone often does not charge a LiFePO4 battery fully, and its regulator is not designed for the load dump when the battery’s BMS disconnects. A DCB DC-DC charger sits between the starter and leisure battery, runs a lithium charging profile and limits the charging current to what the cables and alternator can carry.
Charging in winter
The BullTron Polar batteries have built-in heating of up to 10 A or 150 W. It starts below 0 °C as soon as charging current is present. According to the manufacturer, the battery thus charges down to −30 °C, even when winter camping. Without charging current the heating stays off.
State of charge on the PCU
All BullTron Polar batteries can be integrated into the philippi P-BUS system. The PCU Control Unit then shows state of charge, voltage, current, cell voltages and temperature, together with tanks and loads. No additional shunt is needed for this battery. All models are listed in the overview BullTron LiFePO4 batteries.
Frequently asked questions.
Which battery fits under the seat of my motorhome?
BullTron builds the Polar under-seat models with 350, 540 and 750 Ah at 12.8 V for exactly this. Measure the space under the driver or passenger seat and compare it with the dimensions in the model overview. philippi in Remseck will advise you on the right choice for your vehicle on +49 7146 87 44 0.
Do I need a DC-DC charger for the lithium battery in my motorhome?
Usually yes. The alternator alone often does not deliver the voltage and regulation a LiFePO4 battery needs to charge fully. The high charging current of a lithium battery can also overload the alternator. A DC-DC charger sets a defined charging voltage and limits the charging current to what your cables and alternator can carry.
Can I charge the battery when winter camping?
With a BullTron Polar battery, yes. The built-in heating starts below 0 °C as soon as charging current is present and warms the cells with up to 150 W. According to the manufacturer, the battery thus charges down to −30 °C. Without charging current the heating stays off and does not drain the battery while parked.
How is the 750 Ah battery delivered?
The BullTron Polar under-seat battery with 750 Ah weighs 56 kg. philippi delivers items over 32 kg by freight carrier. You request the battery via the product page and receive an offer including delivery. Smaller models up to 32 kg can be ordered directly in the shop as usual and are sent as a parcel.
Academy
Read on.
LiFePO4 or AGM: Comparison with figures
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Upgrading from AGM to lithium: What else needs to be replaced
Checklist from the charge controller to the main fuse, in the order of procedure — including capacity calculation, the three conversion options,...
Charge Converters, Boosters, or Isolation Relays: What Fits When
Three methods that have the same goal yet differ fundamentally. When a split-charge relay suffices, when a battery-to-battery charger becomes necessary, and...
Integrate the BullTron battery directly into the P-Bus.
The BullTron battery reports its values directly to the P-Bus. The battery management shunt is no longer required, the state of charge...
Advice
Planning to switch to lithium?
Tell us about your vehicle, loads and charging sources, and we will suggest a battery and matching components.