RV, campervan & 4WD

No, an idling car isn't an infinite source of power. In practice budget that your only have about 40 spare amps at idle at 12V, which is roughly 500W of usable spare power. Plan around that limit.

Not loaded up continuously without a larger battery in your system - 2000W at 12V is ~185A, far beyond the 40 spare amps at idle, if it manages to run at all due to the large voltage drop on your small starter battery, you'd drain the battery rapidly and risk cooking the alternator. An additional large battery would supply most of the current that the alternator just tops up is the way to power these size inverters.

A DC-DC charger from the starter/alternator, ideally paired with solar for when you're parked. That combination is the backbone of most van and caravan builds we. Alternatively, a less expensive way is you can use a simple VSR in conjunction with solar so that the battery gets charged correctly most of the time from the solar.

A classic build: either an inverter or an inverter-charger for automatic mains changeover, a separate MPPT for the solar, and a DC-DC (usually 20A) to charge from the tow vehicle. We'll create your kitset around these different functions.

Lights, fridge, water pump, laptop, TV and phone charging are easy on a modest bank; microwave, kettle, toaster and induction are short, heavy hits that drive up battery and inverter size, for these you will need space to fit a lot of battery.

Self-containment is about water, wastewater and a fixed toilet, not your power system, but a reliable 12V setup makes living to that standard far easier. Note the transition period ended 7 June 2026: blue stickers are no longer valid, only the PGDB-issued green warrant now counts (more than 68,000 vehicles have been certified), and freedom camping without it risks an infringement fee.

If it has a 230V AC system connected to shore power, yes - an EWOF is a legal requirement, valid four years, issued by a Registered Electrical Inspector to AS/NZS 3001.2. It covers the 230V side; your 12V DC and solar aren't part of the standard EWOF but should still be done properly.

The extra-low-voltage 12V DC work you can generally do yourself; the 230V AC side must be done to NZ standard and be certified. Note AS/NZS 3001.2:2022 now requires LV (230V) and ELV (12V) systems to be physically separated and isolated, so keep them apart and get the AC signed off.

On a standard alternator, the 20A unit, it charges properly without risking the alternator. Some utes do have a larger alternator as standard as then are intended to power heavier loads like winches and some people do fit aftermarket alternators to get higher amp rates and superior battery charging. We've spec'd exactly this for utes running a CPAP, fridges and charging an e-bike off a small inverter.

A rugged AGM or lead-carbon deep-cycle in a proper box, sized to your fridge and lighting load, with a DC-DC to charge it while you drive.

Often a vibration-loosened terminal or a thin/undersized feed causing voltage drop on compressor surge. Check connections and cable gauge first.

Only within both the alternator's spare capacity and the battery's accept rate - a big DC-DC on a small alternator just overloads it and can cause it to fail. Match the DC-DC to the alternator.

A voltage-sensing relay protects your starter battery so house battery loads can't drain down your starter battery and leave you stranded. We sell automatic battery isolators and relays for this.

Short bursts with a small tool (300w) are fine on a pure sine inverter sized for the tool's surge. larger tools and longer run times you will need a large house battery, not run straight off the starter battery. Running the engine in both cases will always help.

Somewhere it is protected from acid corrosion and from getting wet, and never near a heat source, so not under the bonnet. The back compartment is usually the right place, with the battery leads run forward to the vehicle's battery. Adding a second battery keeps the supply running continuously rather than leaning on the starter battery.