Why Get Solar Right From the Start
Solar is the single most important system in a self-sufficient van build. Get it right and you run your fridge, charge your devices, power your lights, and never pay for a powered campsite again. Get it wrong and you're either constantly running out of power or you've spent A$3,000 on a system that's twice what you needed.
This guide walks through exactly how to size and build a solar system for an Australian van, using components available in Australia at AUD prices.
Step 1: Calculate Your Daily Power Consumption
Every solar system starts with understanding how much power you actually use. Here's a realistic daily consumption for a typical Australian van build:
- 12V compressor fridge (Engel MT45): 25–35Ah/day
- LED lighting (4 hours/day): 4–8Ah/day
- Phone charging (2 phones): 2–4Ah/day
- Laptop (4 hours): 20–40Ah/day (if applicable)
- USB fan (8 hours overnight): 8–16Ah/day
- Diesel heater controller: 2–5Ah/day (winter)
Total typical consumption: 60–100Ah per day
Round up by 20% for inefficiency losses. Target: 80–120Ah usable power per day.
Step 2: Size Your Battery Bank
For lithium batteries (recommended for van life): you can use 80% of rated capacity. For a 200Ah lithium battery, that's 160Ah usable.
Recommended for most builds: 200Ah lithium (LiFePO4)
This gives you 1.5–2 days of autonomy without solar input — enough to handle cloudy days and rest days. The Battle Born 100Ah or Victron 200Ah LiFePO4 batteries are the most commonly recommended in Australian van builds.
Step 3: Size Your Solar Panels
In Australia, a solar panel rated at 200W will realistically produce 80–120Ah of charge per day in good sun (4–6 peak sun hours depending on location and season).
Recommended: 200–300W of solar for a typical build
- 200W: Sufficient for fridge + lights + phone. Marginal in cloudy conditions.
- 300W: Comfortable for most van life needs including laptop use.
- 400W+: Recommended if you work remotely or use high-draw appliances.
Two 200W rigid panels fit on most HiAce, Transit, and Sprinter roofs when mounted flat. For maximum output, use a tilting system or flexible panels on a curved roof.
Step 4: The Charge Controller
An MPPT charge controller is essential — PWM controllers waste 20–30% of your panel output.
For a 200–300W system with a 12V battery: a 20–30A MPPT controller is sufficient. The Victron SmartSolar 100/30 is the most recommended option in Australian builds — Bluetooth monitoring, lithium battery profiles, and Victron's excellent Australian support network.
If you want a dual-input controller that handles both solar and alternator charging in one unit, the REDARC Manager30 is an excellent Australian-made alternative.
Step 5: DC-DC Charger (Alternator Charging)
Solar alone won't keep your battery full on driving days with limited sun. A DC-DC charger (also called a B2B charger) charges your auxiliary battery from your vehicle's alternator while driving.
The REDARC BCDC1225D (25A, dual input) is the most popular choice for Australian builds. It handles smart alternators (post-2014 vehicles), accepts a solar panel input alongside the alternator, and is made in South Australia with direct Australian warranty support.
The Complete Component List for a Standard AU Build
- 2x 200W rigid solar panels
- Victron SmartSolar MPPT 100/30 charge controller
- 200Ah LiFePO4 battery (Battle Born or Victron)
- REDARC BCDC1225D DC-DC charger
- Victron SmartShunt 500A battery monitor
- 40A ANL fuse (between battery and fuse block)
- Blade fuse block (for individual circuits)
- 6B&S wire (main runs), 8B&S (lighter circuits)
This system will run a quality 12V fridge, LED lighting, device charging, and a diesel heater controller indefinitely in most Australian conditions.