Build Your Solar Set Up

The amount of solar you need depends on what you're powering, how much electricity you use each day and how long you plan to camp without driving or connecting to external power.

For a typical 4WD setup running a 12V fridge, LED lighting and charging a few devices, around 200W to 300W of solar can be a useful starting point. However, your actual requirements could be considerably higher, especially if you're running an inverter, Starlink or additional appliances.

The easiest way to estimate your needs is to work out your daily energy consumption in watt-hours (Wh). For example, a fridge averaging 45W while its compressor runs for 10 hours throughout the day would consume approximately 450Wh. Add lighting and device charging, and you might be using around 600Wh daily.

Now consider solar production. A 200W panel receiving four equivalent peak sun hours could theoretically produce 800Wh. Allowing for an illustrative 25% reduction from real-world losses brings that estimate to approximately 600Wh. A 300W array under the same conditions could produce around 900Wh.

These estimates aren't guaranteed. Shade, heat, weather and panel positioning can all affect output. It's worth allowing extra capacity for cloudy days, particularly if you're staying in one place for several nights.

Our calculator above can help you compare different panel sizes, and our Solar Panel Buying Guide explains the differences between available panel technologies.

Your MPPT regulator controls how power from your solar panels is converted into a suitable charging output for your battery. Choosing the right one means checking more than just the total wattage of your panels.

Regulators have limits for solar input voltage, solar short-circuit current and battery charging current. For example, a Victron SmartSolar MPPT 100/30 accepts a maximum solar open-circuit voltage of 100V and can supply up to 30A of battery charging current. It supports 12V and 24V battery systems, but not 48V batteries.

How your panels are connected also matters. When panels are connected in series, their voltages add together while the string current remains approximately the same. When connected in parallel, their currents add together while voltage remains approximately the same. Both arrangements have advantages, depending on the panels, cabling, regulator and expected shading conditions.

Series connections can reduce cable current, but the combined open-circuit voltage must remain within the regulator's limit, including during cold weather. Parallel arrangements increase current and may require additional wiring and circuit protection.

Some low-voltage panels, including certain 9V models, also need to be connected in series with compatible panels to provide sufficient charging voltage.

Always check the panel specifications, regulator limits and battery charging requirements before connecting components. Different panels aren't automatically compatible just because they use the same connectors.

Explore our Victron SmartSolar MPPT regulators for options suited to different solar setups.

Your battery stores the energy generated by your solar panels so you can continue running appliances overnight, during cloudy weather or whenever solar production is insufficient.

The right battery capacity depends on your daily electricity consumption, how many days you want to camp without charging and the battery chemistry you're using. Battery capacity is commonly expressed in amp-hours (Ah), but watt-hours (Wh) give a clearer picture of the energy available.

For example, a typical 12V class LiFePO4 battery has a nominal voltage of approximately 12.8V. A 100Ah battery therefore stores around 1,280Wh of energy, while a 200Ah battery stores approximately 2,560Wh.

For conservative planning, let's assume you use 80% of that nominal capacity, leaving some energy in reserve. A 100Ah lithium battery would provide approximately 1,024Wh of planned usable energy. If your appliances consume 700Wh per day, that's around 1.5 days of operation without additional charging. A 200Ah battery under the same conditions could provide approximately 2.9 days.

These are estimates. Actual usable capacity depends on your battery's specifications, condition, temperature and operating limits. Remember, a larger battery doesn't produce additional electricity. If you're using more energy each day than your solar panels can replace, even a large battery will eventually run down. The goal is to balance battery storage with daily solar production and your expected power consumption.

One of the biggest mistakes is choosing solar panels based purely on wattage without considering the rest of the electrical system. Your panels, regulator, battery, wiring and circuit protection all need to work together.

Undersized cabling is particularly common. Cables that are too small for the current and cable length can create excessive voltage drop, reduce charging performance and potentially overheat. The wiring between your regulator and battery is just as important as the wiring from your solar panels.

Incorrect regulator selection is another issue. An MPPT regulator must be compatible with your battery voltage and the complete solar array. Exceeding maximum solar input voltage or current limits can damage equipment.

Mixing incompatible panels can also cause problems. Panels with different operating voltages or currents may perform poorly together, particularly when connected in series.

Other mistakes include inadequate circuit protection, incorrect lithium battery charging settings, poorly protected cable connections and mounting panels where they're regularly shaded or exposed to excessive heat. Don't forget that panels can generate electricity whenever they're exposed to sunlight, even when other parts of the system are switched off. Solar installations require correctly rated DC equipment and appropriate electrical protection.

Before installing or upgrading a system, check all component specifications and follow the manufacturer's requirements. Seek professional advice where needed. For more practical advice, read our Flexible Solar Panel Installation Guide, which covers mounting methods, cable routing and common installation mistakes.