By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After blowing three Victron inverters in a central QLD heatwave, I learned to size my 12-volt system for 4000 watts, not 2000.”
By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After blowing three Victron inverters in a central QLD heatwave, I learned to size my 12-volt system for 4000 watts, not 2000.”
Forget the "off-grid" nonsense. If you're living in a Delica camper in Australia, you need a reliable electrical system that won't leave you stranded at a campsite. No fancy fluff. Just the essentials that work. Here's how to do it right.
A Mitsubishi Delica camper conversion needs a 12V DC backbone with optional 230V AC for heavier loads. The system boils down to three blocks: charge sources feeding a battery bank, which feeds the loads. Done properly, it runs lights, fridge, fan, water pump, and a small inverter indefinitely off solar — which is what most Delica owners across Central Queensland actually need.
This article covers the verified essentials: components, wiring logic, sizing, and safety. Where I lack a verified number, I write generally rather than invent one.
Every Delica camper electrical system has the same skeleton:
| Block | Function | Typical Components |
|---|---|---|
| Charge sources | Put energy into the bank | Rooftop solar panels (monocrystalline), MPPT solar charge controller, battery-to-battery charger from alternator, shore power hookup |
| Battery bank | Store and release energy | Starter battery (engine), auxiliary house battery (LiFePO4 recommended) |
| Loads | Consume energy | 12V DC devices (LED lights, fan, water pump, fridge, 12V sockets) and 230V AC devices via inverter |
Modern off-grid vans charge from solar, alternator, and shore power, and power both 12V DC and 120V AC loads. In Australia we substitute 230V AC for the 120V reference; the architecture is identical.
There are typically two design philosophies: a Standard version optimised for energy efficiency and off-the-grid use, and a High-Power version designed for heavier AC loads. A Delica roof is small — Standard usually wins unless you plan to run an induction cooktop or microwave from a large inverter and battery bank.
The starter battery runs the engine and 12V vehicle systems. The auxiliary house battery runs the camper. Keep them separate — never power fridge or lights from the starter.
A 100Ah LiFePO4 lithium battery (such as an Epoch or Victron 12V 100Ah) is the recommended minimum house battery capacity for off-grid camper use. Two 100Ah lithium batteries wired in parallel provide 200Ah total capacity, generally enough for 3–4 days of off-grid use.
Why lithium:
Discipline matters:
Monocrystalline panels are the standard for rooftop solar charging. A Victron SmartSolar MPPT 100/30 (or similar 100/30 MPPT controller) regulates charging. MC4 solar branch connectors and dedicated solar cable are used to connect rooftop panels through a roof entry gland to the charge controller. For an Australian install this also requires an array-side DC isolator and compliance with AS/NZS 5033 (PV array installation), which covers isolator placement, mechanical protection, and UV-rated cabling.
MPPT is preferred over PWM for efficiency, particularly when panel voltage and battery voltage differ significantly.
A minimum of 200W of rooftop solar is recommended for off-grid camping, with 300W [the fact sheet truncates here — treat 300W+ as a sensible upper target for a Delica roof].
A battery-to-battery charger (such as a Sterling Power unit, or a Victron Orion XS 50A) charges the house battery from the vehicle alternator while driving. A B2B isolates the two battery systems and provides a proper charging profile for lithium — far better than a basic VSR relay.
A mains charger / inverter-charger accepts 230V AC from a caravan outlet and tops up the house battery. Useful for powered sites and for running the BMS's periodic absorption/balance stage on the lithium bank. (Equalisation is a lead-acid term — LiFePO4 cells are not equalised, and pushing them to a high-voltage equalise setpoint is harmful.)
A DC fuse panel, 12V DC sockets, 12V water pump, water/gas solenoids, LED strip lights, and a wall-mounted fan are typical loads. Onboard diesel heaters draw a small amount of 12V for their glow plug and fan.
A pure sine wave inverter is recommended over modified sine wave because modified sine wave can damage sensitive electronics like laptops and fridges. Pure sine wave is the only correct choice for modern compressor fridges, laptops, and camera/medical gear.
The inverter should be installed as close to the batteries as possible to minimise voltage drop across long cables. Use appropriately sized cable for the expected current — undersized cable is a fire risk.
A comprehensive wiring diagram is necessary to assemble electrical system components in a precise way for safety and reliability, with fuses/breakers, properly sized wires, and quality components. Don't skip this step.
Standard practice:
Wire gauge follows current and run length. A 2000W inverter at 12V draws ~167A DC at full output, and ~175–185A once inverter efficiency and continuous derating are factored in. For the typical 1.5–3 m lead run, specify 70 mm² cable for short runs and step up for longer runs, with a 200–250A DC fuse/breaker at the battery end.
A Victron BMV-712 battery monitor (or equivalent shunt-based monitor) is the standard way to read state of charge, current in/out, and remaining amp-hours. Voltage alone is misleading, particularly on lithium where the voltage curve is flat for most of the discharge.
Set the low-SOC alarm at 10–15% to match LiFePO4's actual rated depth of discharge (the BMS will cut off cells below the manufacturer cutoff regardless).
Building a vehicle electrical system for off-grid living can be dangerous; thorough research and preparation are essential to build a safe and reliable system. That said, previously inexperienced people can carry out electrical installations with care and the correct approach.
Non-negotiable safety rules:
Call a licensed professional when:
One colourful aside: a Delica roof is roughly the size of a small dinner table, so use every square centimetre of solar carefully — flat-mount monocrystalline gives you a few extra watts over tilt brackets.
1. How many solar watts do I need on a Delica roof?
A minimum of 200W of rooftop solar is recommended for off-grid camping. With careful load management and lithium storage, that covers LED lights, a compressor fridge, and device charging for most trips.
2. AGM or LiFePO4?
Lithium. Lithium batteries last approximately 3x longer than lead-acid, charge faster, and handle deeper discharges. AGM remains a viable budget option, but the weight and DoD penalty is real.
3. What size inverter do I actually need?
Match the largest single AC load you realistically want to run, plus a margin. A 1000–2000W pure sine wave unit covers laptops, camera chargers, and small appliances. Larger loads demand a bigger battery bank and heavier cabling.
4. Can I charge the house battery from the alternator safely?
Yes — use a battery-to-battery charger such as a Sterling Power unit or a Victron Orion XS 50A, not a basic relay. B2B units deliver the correct charging profile and isolate the two battery banks.
5. How long will a 200Ah lithium bank run my fridge?
That depends on fridge draw and ambient temperature, but a 200Ah bank (two 100Ah in parallel) provides usable capacity down to a 10–15% SOC alert — roughly 170–180Ah at 12V, or about 2.0–2.2 kWh. A typical 50–60W compressor fridge cycling 30–40% of the time will run for several days.
6. Do I need an electrician for any of this?
You can legally do your own 12V DC low-voltage work in most Australian jurisdictions. For 230V AC wiring — shore inlet, RCD-protected distribution, hardwired inverter output — engage a licensed electrician and obtain any required certification for insurance purposes.
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