Power Supply for Off-Road and Expedition Vehicles – All Components at a Glance
Vehicle self-sufficiency is a calculation, not a matter of equipment brand. It starts with your daily consumption in ampere-hours: cooler, parking heater, lights, water pump, laptop, coffee machine. This determines the necessary usable battery capacity – and from that, how much you need to recharge each day. For recharging, you have three sources in the vehicle: the alternator while driving, solar when stationary, and shore power or a generator if both are insufficient. In this category, you will find components for all three methods – batteries, chargers, charge boosters, vehicle alternators, combi inverters, charging current distribution, and solar charge controllers. Philippi develops and manufactures some of these components in its own factory in Germany and supplements them with selected brand products.
Batteries The service battery determines how long you can go without recharging. What matters is not the printed capacity, but the usable capacity: LiFePO4 batteries like the SB 12V210E NOMIA from SuperB deliver their 210 Ah fully usable, which corresponds to approximately 500 Ah lead-acid – at a weight of 23 kg. This is the real leverage in a vehicle because payload and installation space are limited. In addition to the SuperB series (NOMADA, EPSILON, NOMIA), you will find BullTron batteries for 12 V and 24 V, the MLI Ultra from Mastervolt, and with the LB48/105, also a 48 V battery for larger expedition setups. Pay attention to the permissible temperature range: charging lithium is usually only allowed above 0 °C, discharging with the NOMIA down to –20 °C. Those traveling in winter must position or temper the battery box accordingly.
Charge Boosters In a vehicle, the alternator is the most important charging source – but rarely a good one. Modern vehicles regulate the generator voltage downwards depending on consumption, plus there are voltage peaks during overrun and voltage drops over long cables to the superstructure. A charge booster like the DCB 12V converts this into a clean three-stage charging characteristic and truly fully charges the leisure battery even on short trips. The series ranges from the DCB 12V with 12 V input and 60 A charging current, to the DCB 24V (12 V to 24 V, 30 A), up to the DCE 36V and DCE 48V – so you can charge a higher-voltage on-board electrical system without installing a second alternator. Practical in the vehicle: soft start relieves the V-belt when starting, operation is fanless and thus dust-insensitive, the temperature range extends from –20 °C to +60 °C with over 96% efficiency. For voltage adaptation without charging function – such as a 24 V on-board system to 12 V consumers – there are the DD- and PV-voltage converters from alfatronix.
Battery Chargers For shore power at the campsite or in the workshop, philippi manufactures the ACE series in Germany: ACE 12/30, ACE 12/44, ACE 12/64, and the high-power device ACE 12/90 for 12 V, as well as ACE 24/25 and ACE 24/30 for 24 V. They charge up to three battery banks simultaneously – for example, leisure, starter, and a third bank –, operate fanless with a heat sink in the housing base, and accept 90–265 V AC without power loss, which is important when traveling with weak grids. Seven charging programs cover wet, lead-calcium, GEL, AGM, and lithium batteries; the ACE 12/30 is designed for 120–250 Ah. Remote displays like F-ACE and FAL bring the values into the cab. Additionally in the assortment: ChargeMaster Plus from Mastervolt, the BatteryLink BS 7607 from Blue Sea Systems, and high-power 24 V devices from cristec.
Vehicle Alternators If you drive a lot and stand still little, the cheapest energy comes from the engine. High-performance alternators from Balmar are available in 12 V with 100 A, 120 A, and 170 A (XT Series, with single or dual foot) as well as in 24 V with 70 A and 140 A. The regulation is crucial: external regulators like MC 618 (12 V), MC 624 (24 V), and ARS-5 provide a multi-stage characteristic instead of constant voltage, the equalizer CFII supplies a second bank. Because belt tension and heat determine the lifespan in a vehicle, belt tensioners (Belt Buddy), adjustment arm, and matching pulley sets are part of the planning. From Mastervolt come the Alpha Pro III and the Alpha 24/150 MB. If driving performance and solar are not sufficient, the Panda 5000i generators from Fischer Panda supply power independently of engine operation.
Combi Inverters 230 V in the vehicle comes either from a pure inverter or from a combi device that combines inverter, charger, and mains transfer switch. The XTM and XTH combi inverters from Studer cover 1500 to 3500 VA for 12 V and 24 V on-board electrical systems, charge with up to 100 A, and also start consumers with high inrush current via Smart-Boost by adding battery power and shore power. Where only inverting is needed, the sine wave devices of the AJ series from AJ 275 to AJ 2100 / AJ 2400 are sufficient; Mastervolt offers Mass Sine and Mass Combi Ultra. Operation and monitoring are done via RCC-02 or RCC-03, the additional module RCM 10 reduces standby consumption – a real item in the vehicle, because quiescent current works against battery capacity over days.
Charging Current Distribution To prevent the starter and leisure batteries from draining each other, the charging current distribution automatically separates and connects them. For this purpose, philippi manufactures the VHR 200 isolation relay, the 40A and 70A automotive relays, the BLA charge equalizer, as well as cable sets and the ACE-T-CABLES for P-Bus connection. From Blue Sea Systems come isolation relays such as the ACR 12/24, the ML 500A 12V ACR with manual override for emergencies, the ACR Mini, and the complete Add-A-Battery kit for easy second battery retrofitting. The RCE charging current distributor from Studer and Mac Plus from Mastervolt complement the assortment.
Solar Charge Controllers Solar is the source for long stationary periods – but limited in the vehicle by the roof area. The MPPT solar charge controller VT from Studer gets the maximum out of existing modules and is available as VT 40, VT 65, and VT 80 with 40, 65, and 80 A charging current for 12 V, 24 V, and 48 V batteries, with IP 54 protection and less than 1 W reverse current in night mode. The Solar ChargeMaster from Mastervolt is the alternative. How much you actually harvest and consume is shown by a battery monitor like the BLS from philippi – without measurement, every self-sufficiency calculation remains an estimate.
Are you unsure how consumption, battery capacity, and charging sources fit together in your vehicle? Our team will advise you personally – from the initial consumption calculation to the finished system.
FAQ
Do I need a charge booster? In most newer vehicles, yes. As soon as the alternator is regulated depending on consumption, the charging voltage drops after a short time, and the leisure battery will never be fully charged via a simple isolation relay. A charge booster like the DCB 12V generates its own three-stage charging characteristic and additionally compensates for the voltage drop of long cables to the superstructure.
How big does my leisure battery need to be? First, add up the daily consumption of all consumers in ampere-hours and multiply it by the number of days you want to bridge without recharging. For LiFePO4, calculate with the fully usable capacity – the SB 12V210E NOMIA, for example, with 210 Ah, which corresponds to about 500 Ah lead-acid. With lead-acid batteries, however, you must leave a significant portion of the capacity as a reserve.
Is solar alone sufficient for self-sufficiency in the vehicle? Usually not. The usable roof area is limited, and the yield varies greatly with season, location, and shading. Solar covers the base load well when stationary, while driving power via a charge booster recharges the main amount; a shore power charger or a generator like the Panda 5000i remains the fallback.
Lithium or lead in an expedition vehicle? Lithium offers significantly more usable capacity per kilogram and per liter of installation space, which is crucial with limited payload. The price for this is the temperature limit: charging LiFePO4 is typically only allowed above 0 °C. Those driving in winter must choose or temper the battery location accordingly.
Do the devices work in 12 V and 24 V vehicles? Yes. The ACE chargers are available for 12 V and 24 V, as are the XTM and XTH combi inverters, and the VT solar charge controller is configurable for 12, 24, and 48 V. For vehicles with a 24 V on-board system and 12 V consumers, voltage converters are also available.
How do I monitor the system in operation? Via a battery monitor like the BLS, which displays voltage, current, and state of charge. Chargers and charge boosters from philippi can be integrated into a common system monitoring via the P-Bus and ACE-T-cables, Studer devices via the remote controls RCC-02 and RCC-03.
