How to Set Up a Solar Power System for Your Overland Vehicle
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Solar power is the backbone of any serious overland build. Here's how to design and set up a system that actually works off-grid.
Nothing kills an overland trip faster than a flat battery. Whether you're running a fridge, charging devices, powering lights, or keeping communication gear alive — a properly designed solar power system means you never have to worry about power again. The good news: setting one up is more straightforward than most people think, as long as you follow the right steps.
At Advanced 4x4, we stock the full Victron Energy range — the most trusted name in off-grid power management — and our team can help you design and fit a system that suits your vehicle and your adventures.
☀️ Step 1: Calculate Your Daily Power Consumption
Before buying any equipment, you need to know how much power you actually use. List every electrical device you run off-grid and estimate daily usage:
- 12V fridge (e.g. 50L) — approximately 30–50Ah per day
- LED lighting — approximately 5–10Ah per day
- Phone/device charging — approximately 5Ah per day
- Communication gear (radio, satellite) — varies widely
- Laptop / camera charging — approximately 10–20Ah per day
Add it all up. That's your minimum daily consumption in amp-hours (Ah). Your battery bank needs to store at least 2x your daily consumption to avoid deep discharge, and your solar input needs to replenish it within a reasonable number of daylight hours.
🔋 Step 2: Choose Your Auxiliary Battery
Your solar system charges an auxiliary (secondary) battery — completely separate from your starter battery. Two main options:
- AGM (Absorbent Glass Mat) — reliable, affordable, handles partial state of charge well. Good entry-level choice. Usable capacity is approximately 50% of rated capacity.
- LiFePO4 (Lithium Iron Phosphate) — lighter, more efficient, 80–90% usable capacity, longer cycle life. Higher upfront cost but better long-term value for serious overlanders.
Rule of thumb: Size your battery bank at 2x your daily consumption. For 60Ah daily use, aim for a 120Ah AGM or 80Ah lithium bank minimum.
☀️ Step 3: Size Your Solar Panels
Solar panels are rated in watts (W). In South Africa, you can typically expect 4–5 peak sun hours per day in good conditions. To calculate the panel size you need:
Daily consumption (Ah) ÷ peak sun hours × system voltage = panel wattage required
Example: 60Ah daily ÷ 5 hours × 12V = 144W minimum. Add 20–30% buffer for inefficiency and cloudy days — so a 200W panel is a practical starting point for moderate consumption.
For roof-mounted setups, rigid monocrystalline panels offer the best efficiency. Flexible panels are lighter but degrade faster under SA heat.
🔌 Step 4: Install a Victron MPPT Solar Charge Controller
Your solar panels connect to your battery via an MPPT (Maximum Power Point Tracking) charge controller. This is the brain of your solar system — it extracts maximum power from your panels and charges your battery safely and efficiently.
The Victron SmartSolar MPPT range is our top recommendation:
- Bluetooth connectivity — monitor and configure via the VictronConnect app
- Available in sizes from 75/10 (small setups) to 150/70 (large arrays)
- Compatible with AGM, gel, and lithium batteries
- Built-in load output for direct 12V device connection
Match your controller to your panel wattage and battery voltage — our team can help you select the right model.
🚗 Step 5: Add a DC-DC Charger for Driving Charge
Solar alone won't always keep up — especially on multi-day drives through overcast conditions. A DC-DC charger (also called a battery-to-battery charger) charges your auxiliary battery from your alternator while you drive, without risking damage to your starter battery or modern smart alternator.
Victron's Orion-Tr Smart DC-DC chargers are isolated, Bluetooth-enabled, and compatible with smart alternators — essential for modern Euro 6 vehicles like the Ford Ranger Next Gen and Toyota Hilux GR Sport.
📊 Step 6: Monitor Everything with a Victron BMV
A battery monitor tells you exactly how much charge is left in your auxiliary battery — in real time. The Victron BMV-712 is the gold standard: accurate state-of-charge display, Bluetooth connectivity, and historical data logging via VictronConnect.
Without a battery monitor, you're guessing. With one, you know exactly how many hours of power you have left at your current consumption rate.
📞 Let Us Design Your System
Every overland build is different. Our team at Advanced 4x4 can help you design a Victron-based power system that matches your vehicle, your consumption, and your budget — and fit it professionally at our Strand fitment centre.
📞 021 569 7238 | 📧 sales@advanced4x4.co.za