Batteries and storage
LiFePO4 battery for boats.
Convert, charge, monitor.
A LiFePO4 battery gives you more usable energy on board at lower weight than lead-acid or AGM. For the on-board system to suit the lithium battery, the charger, alternator, fusing and monitoring have to match. philippi supplies BullTron Polar batteries with heating and the matching components from Remseck am Neckar, Germany.
Charging down to −30 °C with heating (Polar).
6 to 540 Ah in 12 V and 24 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, protection.
What has to be replaced when switching to lithium
- Charger: It needs a LiFePO4 charging curve. The philippi ACE chargers are designed for wet, GEL, AGM, lead-calcium and LiFePO4 batteries.
- Alternator: On its own it often does not provide the voltage and regulation a LiFePO4 battery needs to charge fully, and the high charge current of a lithium bank can overload it. A charge booster sets a defined charging voltage and a limited charge current.
- Fusing: A main fuse belongs directly at the terminal, see high-current fuses, plus a battery main switch.
- Monitoring: You should be able to see the state of charge and cell voltages without opening the battery.
The article Switching from AGM to lithium explains in detail what has to be replaced.
Charging in the cold: Polar with heating
The BullTron Polar batteries have a built-in heater with up to 10 A or 150 W. It starts below 0 °C as soon as charging current is present and warms the cells directly. According to the manufacturer, the battery can therefore be charged down to −30 °C. Without charging current the heater stays off and does not drain the battery in winter storage.
Finding the right size
The capacity follows from your daily consumption and the number of days you want to manage without recharging. The load balance and the battery capacity calculator take you through it step by step. All BullTron models with voltage, capacity, dimensions and weight are listed in the overview BullTron LiFePO4 batteries.
Monitoring in the philippi on-board system
All BullTron Polar batteries can be integrated into the philippi P-BUS system. The Control Unit PCU then shows state of charge, voltage, current, cell voltages and temperature, together with tanks and loads. An additional shunt is not needed for this battery, see Connecting a BullTron battery directly to the P-Bus.
Frequently asked questions. Answered briefly.
Can I simply replace my AGM battery on board with LiFePO4?
The battery itself often fits the same compartment, but the on-board system around it has to match. Check whether your charger has a LiFePO4 charging curve, how the alternator charges and whether the main fuse sits at the terminal. For the design of your boat, philippi in Remseck will advise you on +49 7146 87 44 0.
Do I need a charge booster for the lithium battery on board?
Generally, yes. The alternator alone often does not provide the voltage and regulation a LiFePO4 battery needs to charge fully, and long cables with voltage drop make this worse. In addition, the high charge current of a lithium bank can overload the alternator. A charge booster sets a defined charging voltage and a limited charge current.
Can I charge the battery on board in winter?
With a BullTron Polar battery, yes. The built-in heater 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 can therefore be charged down to −30 °C. Without charging current the heater stays off and does not drain the battery during lay-up or winter storage.
How do I see the state of charge of the lithium battery?
BullTron batteries show the state of charge and cell voltages in the BullTron app via Bluetooth and Wi-Fi. In the philippi on-board system it also works via P-BUS: the Control Unit PCU then shows state of charge, voltage, current, cell voltages and temperature of the battery, together with tanks and loads, without an additional shunt.
Academy
Read on. In the philippi Academy.
LiFePO4 or AGM: Comparison with figures
It's not the price per ampere-hour that matters, but the cost per ampere-hour withdrawn over the service life. The calculation, the edge...
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? We design it with you.
Tell us about your boat, loads and charging sources, and we will suggest a battery and matching components.