PORTABLE POWER PACKS
When you can't fit an under-bonnet second battery.
Very few of today’s 4WDs have under-bonnet space for a full-sized deep cycle battery to power a fridge and other camping equipment. The solution is a power pack.
Our own OTA 75 Series LandCruiser bush vehicle is set up with a 100 amp-hour deep cycle battery under the bonnet and our Tray-Tek slide-on camper has its own 100Ah battery. We have a Projecta 120-watt folding solar panel and the camper has a fixed 120-watt roof-top solar panel. Our charging back-up for the solar panels, should the sun not come out to play, is a Honda 10i petrol-powered generator.
We have all the amps we need.
However, we’re often testing other people’s vehicles - press-test 4WDs that aren’t set up for camping - so we have additional kit that we employ.
The key component is a power pack – our main one is an eight-year-old Thumper 75Ah model – that can easily run the fridge and camp lights at night, and is also a jump-starter should the main vehicle battery go flat. We also have a second, 36Ah Thumper power pack.
When driving during the day we charge the power packs by plugging them into cigarette lighter sockets. This isn’t the ideal charging regime, because current flow isn’t regulated in the same way that a dedicated charger does it, but it works well enough in the short term. If we owned the vehicle, we’d hard wire the power pack chargers to the battery.
When driving, we run the fridge off a vehicle power outlet and when we camp we plug it into a power pack that runs it overnight. When we set off next day, we plug the power pack into the vehicle supply to recharge it and connect the fridge to the vehicle power outlet.
One some test trips we’re not driving a vehicle every day: we may be camped somewhere, exploring on foot, or checking out and videoing camping equipment. That’s when our second power pack comes into play.
We use one power pack overnight and recharge it using the portable solar panels next day. In the meantime the second, charged power pack runs the fridge during the day. At night we swap the charged and partially discharged power packs, running the fridge overnight and next day off the charged one and recharging the other one with the solar panels.
It’s possible to do all this with one power pack, because the inbuilt charger allows the fridge motor to interrupt the solar charging regime when required,
but we prefer the inherent back-up nature of having two power packs.
What power pack for you
If you want reliable camp power availability, don’t take the cheap route. You won’t get 24-hr fridge operation and diesel-engine jump-start capability from anything costing less than around $400. The best units are around twice that much.
We’ve tested cheaper units and they just won’t do the job. You don’t want to risk losing a fridge full of food, or worse, eating food (or beer) that hasn’t been kept cold enough.
Power packs can be semi- or fully-portable. The battery box type is designed to be mounted in the back of a wagon or ute, close to the fridge. The fully-portable type has carry handles, allowing it be moved more easily from vehicle to vehicle – especially handy if it’s to be used as a jump-starter.
The basic system involves buying a purpose-designed battery box and a deep cycle battery to go inside it. As you’ll see from our accompanying battery story, 75-100Ah is the benchmark for camping power.
The best battery boxes incorporate a smart charger and several 12V outlets. Pricing for the box, without battery, is $90-$170. Add a top-quality AGM battery and inbuilt 240V inverter and you won’t get much change out of $700-$800.
Portable power packs are priced according to Amp-hour ratings and range in price from around $500 up to $2200.
If you want to employ the solar-charging swap system we use you can buy two medium-sized units rather than one big one: say, two 60Ah units, instead of one 105Ah one.
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