Balance Of Power


Camping technology has evolved radically over the years, but nothing has revolutionised our outdoor way of life quite like the portable fridge / freezer. The ability to keep food cold for an indefinite period has not only changed our camping experience, but also given us the option of travelling further, for longer.

However, with the introduction of the portable fridge / freezer came the need for additional battery power. This opened the door to another form of camping technology − dual-battery systems.

Generally speaking, dual-battery systems come in two forms: on-board units, (typically mounted within a vehicle’s engine bay), and those packaged in a portable-power pack. The problem lies in deciding which solution is best.

To be clear, there’s no right or wrong answer, as both systems have their strengths and weaknesses (as can be seen in the table below). The trick is to figure out which auxiliary battery system best suits your needs. Although the table below may seem to favour the portable-power pack, you need only run out of boot space to realise the true value of an onboard dual-battery system.

That said, the two most significant features of these two systems are space and mobility. What you need, is to decide which aspect is more important to you.

There are various dual-battery systems available on the market, but in National Luna’s case, we’ve opted for the tried-and-trusted durability of an intelligent solenoid system. In fact, 18 years ago, we were one of the first companies to develop such a setup. This unit is designed to be a compact, fully-automated split-isolator system that piggy-backs off your vehicle’s main battery. In other words, the dual-battery isolator runs parallel to your vehicle’s OE wiring and features zero interference.

What’s more, the isolator is designed as a low-loss, high-current system that places particular emphasis on simplicity, rate of recharge, and long-term reliability.

Some competing, more electronic-savvy dual-battery systems (such as an intelligent DC to DC charger), are often three times the price. Even more important is that while these so-called intelligent chargers are great at prolonging battery life (due to their trickle-charge feature), in a real-life scenario, they often recharge your battery at a much slower rate, in some cases requiring up to 48 hours to replenish a deep-cycle battery. In comparison, a high-current solenoid system (when paired with the right battery type), can restore full battery power within 6 hours or less.

In terms of price, you can expect to pay approximately R2 945 for a National Luna Portable Power Pack, while the National Luna On-Board System typically retails for R1 999 (excluding the battery itself). Both products can be found at all major outdoor and 4×4 stores.

Visit for more overland solutions, or call (011) 452 5438. Boasting the largest range of 12V fridge / freezers in the world, National Luna is the only commercial manufacturer of off-road fridges in SA, and the preferred supplier to all major off-road trailer and caravan manufacturers.