Campervan, Motorhome & RV Power Systems
A reliable campervan or motorhome system keeps a dedicated house battery separate from the engine-start battery, and charges it from three sources: the alternator while you drive, solar while you're parked, and mains when you're plugged in. We supply the whole setup, deep-cycle house batteries, DC-DC chargers, pure sine wave inverters, solar and monitoring, and we'll size it to how you actually travel rather than to a parts list.
The part most people get wrong is alternator charging. A plain alternator holds ~14.0-14.1V, which is fine for the starter battery it was designed for but too low to put a deep-cycle house battery through its proper staged charge, so it chronically undercharges it especially if that is the only method of charging you have. A modern smart alternator can be worse, it varies its voltage to save fuel and a simple relay causes intermittent charging. A DC-DC charger takes what the alternator gives and converts it into the staged profile the house battery actually needs. Ours has an input low-voltage cut-off at 12.8V so it can't flatten your starter battery, and the 12V 20A model with built-in MPPT takes the solar as well.
For 230V appliances, size a pure sine wave inverter by the sum of largest loads you'll run at once plus surge headroom, and remember the current on the 12V side: I = P/V (current = power / voltage), so a 1500W load pulls ~125A from a 12V battery, and the cable and fusing have to be specced to carry that.
If your van is a connectable installation, a caravan or motorhome with fixed 230V wiring, it falls under AS/NZS 3001.2:2022, which is compulsory from 12 November 2026. The 12V DC side you can generally do yourself with the correct cable, fusing and connections. The fixed 230V wiring has to be done and certified by a registered electrician, and the 2022 edition also restricts where a lithium battery can be sited in the living space. We supply components that suit a compliant install and can point you to an electrician to assist further as necessary. More answers in our RV, campervan & 4WD FAQ and our DC-DC & charging FAQ.
Common questions
What size inverter do I need to run a coffee machine in a campervan?
Most pod or capsule machines draw 900 to 1200W and espresso machines 1200 to 1500W, and both surge higher at start-up from the onboard pumps. For a pod machine use a 1700W or higher pure sine wave inverter; for an espresso machine go to 2200W to cover the surge. Then match it to the battery: a 1500W load pulls ~125A from a 12V battery, a house battery that is too small will go low voltage under this amount of demand, so spec it for this amount of current discharge.
How do I charge my house battery while driving?
Through a DC-DC charger if you can, a plain alternator through a VSR holds ~14.0-14.1V, too low to fully charge a deep-cycle battery by itself. The DC-DC charger converts the alternator's output into the staged charge the house battery needs. On a standard alternator the 20A unit is the right size, it charges properly without risking the alternator. A good alternative, if you want a lower cost option, is a VSR with other chargers that regularly charge the battery with the correct charging voltages. That achieves a near-optimal result overall, as at least some of the time, the battery is getting correctly charged.
Can I install a lithium battery inside my caravan in NZ?
Not just anywhere. AS/NZS 3001.2:2022, compulsory for connectable installations from 12 November 2026, restricts where a lithium battery can be sited in a habitable living area: generally it needs a sealed enclosure or a sealed-off space vented to the outside, and the battery itself has to meet the relevant battery standard. Where the weight saving doesn't matter, an AGM or lead-carbon house battery bypasses that whole requirement, and that's what we fit in most vans.
Do I need a registered electrician to install my campervan power system?
For the 12V DC side, generally no, you can do it yourself with the correct cable, fusing and connections. For fixed 230V AC wiring in a caravan or motorhome, yes: it's a connectable installation under AS/NZS 3001.2 and the work has to be done and certified by a registered electrician. We supply the components and can refer you to an electrician as required.
How much solar do I need on a campervan?
It depends on your daily energy consumption and how long you stay parked up. For an overly simplistic rule, size the solar to put back what your fridge, lights and devices use on an average day, and let the alternator top up the rest through the DC-DC charger while you drive.