The Perfect 4WD Power System
Every 4WD owner has different power needs — from weekend campers with a fridge and lights, to full-time overlanders running induction cooktops and satellite internet. The good news is that a well-designed 12V lithium system scales to any requirement.
Here's how to spec the perfect setup for your rig.
Step 1: Calculate Your Daily Draw
Start with a load audit. For each electrical item, estimate:
- Current draw in amps (A)
- Hours of use per day (hr)
- Daily amp-hours = A × hr
Typical 4WD daily loads:
| Item | Current | Hours/Day | Daily Ah | |---|---|---|---| | 60L compressor fridge | ~4A avg | 24 | 40Ah | | LED interior lights | ~2A | 4 | 8Ah | | Water pump | ~5A | 0.5 | 2.5Ah | | Phone charging | ~1A | 4 | 4Ah | | 12V tyre inflator | ~15A | 0.3 | 4.5Ah | | Total | | | ~59Ah/day |
A good rule: add 30% to your calculated total for inefficiencies, cable losses, and unexpected loads. So ~77Ah/day for this example.
Step 2: Size Your Battery Bank
For weekend camping (2 nights away): Multiply daily draw by nights of autonomy (without solar): 77Ah × 2 = 154Ah. A Revolution Power 12V 200Ah gives comfortable headroom.
For extended touring: Add solar to the equation. A 200W panel in good sun generates ~50–80Ah/day in Queensland and WA. With 300W solar, a single 12V 200Ah battery covers most overlanding scenarios indefinitely.
For full-time travellers: Consider 2× 200Ah in parallel (400Ah total) with 400W solar for maximum autonomy and resilience.
Step 3: Choose Your Charging Sources
Solar (Primary Charge Source for Touring)
Victron SmartSolar MPPT controllers are our recommendation for lithium. They:
- Correctly handle LiFePO4 charge profiles
- Connect to VictronConnect app via Bluetooth
- Maximise harvest in partial shade via true MPPT algorithm
Minimum for most setups: 200W panel + MPPT 75/15. Better for touring: 200–300W + MPPT 100/30.
DC-DC Charger (Alternator Charging)
Never connect lithium directly to your alternator. Always use a battery-to-battery (DC-DC) charger.
Victron Orion-Tr Smart 12/12/30A is the go-to — 30A charge rate, Bluetooth monitoring, automatic engine-detection start/stop.
Mains Charger (When Shore Power is Available)
A Victron Blue Smart IP65 12V/25A handles camp power and home garage charging. LiFePO4 profile built in.
Step 4: The Ideal Component List
For a typical serious touring 4WD:
| Component | Recommended | Notes | |---|---|---| | House battery | RP 12V 200Ah LiFePO4 | Most popular touring size | | Solar panel | 200–300W rigid | Roof mount for reliability | | MPPT controller | Victron MPPT 100/30 | Handles up to 400W | | DC-DC charger | Victron Orion-Tr 30A | Must-have for lithium | | Battery monitor | Victron BMV-712 | Real SoC via shunt | | AC charger | Victron Blue Smart 25A | Shore power |
Total System Cost vs AGM
Initial cost is higher for lithium — typically 2–3× the battery cost. But over a 10-year touring life:
- AGM replacement every 2–3 years = 3–4 replacements = $1,200–$2,400
- LiFePO4 replacement after 10–15 years = $700–$900
Lithium is cheaper over time. And you get better performance the entire time.
Ready to spec your system? Get a custom quote from our team — we'll design the right setup for your vehicle and budget.