Andrew and Peta Murray from Top Wire Traveller took one of our Dometic 120W portable solar panels out to far Western New South Wales in summer for an extreme test. How well did it handle the conditions? Let’s find out!

If you’re a keen camper, then a portable solar panel is pretty much an essential item. Even basic camping is so much easier if you have a second battery.

Clearly, you’ll need something to charge your battery. While you can charge the second battery from your vehicle, you’ll also need a backup for when you’re set up at a campsite.

A solar panel is perfect for this task.

The Dometic folding solar panel.

Portable solar panels are convenient. They pack up into a compact size and will fit in any vehicle. And you can easily move them around to catch full sunlight.

A portable panel is ideal for camping, especially if you’re planning to go off the grid.

Recently we tested a Dometic 120W portable solar panel in an extreme climate. After all, if you’re going to review something, then why not throw a few obstacles in its way? And that’s what we did.

We caretake out near Cameron Corner in far western New South Wales every January. No, we don’t camp… we’re not that crazy! Instead, the luxury of an air-conditioned cabin keeps us from expiring.

Daytime temperatures regularly hit 40-45°C or higher. The efficiency of solar cells drops as temperatures rise past 25°C. Despite popular belief, solar panels don’t like heat at all… which seems a bit strange, given they spend their lives in the sun.

I won’t bore you with the details of why this is so. Suffice to say, it’s all to do with the internal components of each cell and the effects of heat on them.

A hot climate is the ideal place to see how Dometic’s 120W portable panel performs. We had the heat and we had a panel… so it was time to try it out.

What’s in The Box?

The Dometic 120W portable solar panel is officially called a PS 120A. It comes in a thick cardboard box. Once you break into this box, you’ll find the fun bits neatly packed in a carry bag.

The panel comes supplied with:

• Folding portable solar panel with solar controller fully wired.
• Grey 50A Anderson plug pre-wired to the controller output.
• 5m cable with Anderson plugs both ends.
• Anderson plug to alligator clamps adaptor cable.
• Carry bag.
• Battery temperature sensor.
• Installation and Operating Manual.

Dometic’s portable panel comprises two 60W monocrystalline panels, joined with a hinge and wired in parallel. The stand swings out and support arms hold the legs in place. It has four positions, from 45° to around 15° from horizontal.

The solar panel can be set at four different angles.

The panel folds into a neat rectangular unit, with two sturdy clips and a spring-loaded carry handle. There’s space inside to store the cables. A soft carry case with zipper, handle, and shoulder strap completes the picture.

 
All cables are 4.0mm² (or roughly 12AWG), which are sized correctly for the rated output current.
Let’s take a closer look at the solar controller.

Dometic Solar Controller

The Dometic Portable Solar Panel Kit is rated at 6.63A and 18.1V at maximum power (at 25°C ambient temperature), giving a total of 120W of power.
A solar controller’s mounted to the back of the panels. It takes the power from the panels and converts it into useful 12V power.

 
The controller has 25%, 50%, 75%, and 100% LED battery charge indicators, plus power and error LEDs. The terminals consist of a pair each (+ve and -ve) for:

1. Solar panel input,
2. Battery output,
3. Load output.

The Load output allows you to connect 12V devices directly to the solar controller. The obvious downside is you only have power when the sun’s shining.

Still, it’s a handy feature. For example, you could connect a USB charging point for phones. In this case, it doesn’t matter whether the power goes on and off intermittently.

Emerging from the left side of the solar controller is a temperature sensor. You can tape this to the side of the battery you’re charging. This helps the controller to regulate the charge to the battery, depending on temperature.
Unfortunately, the temperature sensor’s cable is very short. You’d need to have the portable panel right at the battery. The idea is good, however the cable’s too short to be much use.

Okay… now we’ve seen what’s in the kit, let’s see how it performs in the real world.

Our Tests

We did two different tests to see what the Dometic portable solar panel is capable of. Real-world testing is the only way to get useful results… and it tells you whether the manufacturer has exaggerated their claims.

Test #1. Charging A Flat Battery

The first test was a simple one…
If our deep cycle battery is flat, how long does the portable panel take to charge it?
The outback station we were looking after has work vehicles. One had a 105Ah AGM deep cycle battery, removed from the ute 18 months prior to our test. The battery was fine when it was removed. It was taken out because the battery bracket and supports disintegrated on the rough roads out here!

 
We knew the battery had been sitting for way too long without being charged. So it was ideal for our test.
And it was definitely flat… a quick check with a multimeter showed 6.1V.
We connected the Dometic portable solar panel using the supplied cabling and alligator clamps. I checked the battery voltage every hour. Here are the results. And note the ambient temperature readings… it was a hot day!

A few notes about the test:

• At 2pm when it was 40.3°C in the shade at the battery, we measured 46.8°C near the panel in full sun.
• The battery wasn’t connected to any loads.
• It was December 31, New Year’s Eve. At this time of year at this latitude, the sun is directly overhead for much of the day. So, we laid the panel as flat as the stands allow – around 15° from horizontal. Then every hour, I rotated the panel to optimise the angle of the sun.
• When I checked the voltage every hour, I disconnected the alligator clamps and allowed the voltage to settle before taking a reading.

The outcome?

As you can see above, the portable solar panel charged the battery within the first hour. From then on, it maintained a constant voltage of 12.2V.

It’s important to understand the solar controller on the panels isn’t a battery charger. It simply supplies 12V (nominal). A battery charger would run the battery through various charging cycles, charge it to 14.4V, then maintain 13.6V.

But the solar panel isn’t intended to be used as a battery charger. So the 12.2V final charge is fine… and exactly what we’d expect any solar panel with a controller to do.

In this test, the portable solar panel did a great job. In fact, it caught me out with how quickly it charged the battery.

A definite pass for this test.

Test #2. Maintaining Charge to A Battery

The second test is designed to test the portable solar panel in a more typical camping situation…
Does the solar panel generate enough power to keep a deep cycle battery charged indefinitely?
To complete this test, we needed to do a few minor modifications. Allow me to explain.

We have a truck camper with a dual battery system in the truck. It has a 100Ah deep cycle Lithium battery, charged via a Battery Management System (BMS). The BMS takes input voltage and current, then optimises the charge to the battery. It’s a full-blown battery charger.

The BMS needs raw input power from the solar panels. Any solar controller (regulator) will interfere with the BMS. So, I bypassed the Dometic solar controller… a simple wiring change. Just disconnect both the input cables from the solar panel and the output cable, then join them together.

In this mode, our on-board BMS gets full current and voltage from the portable solar panel. The BMS then supplies power to the Lithium deep cycle battery as needed.

To provide a load, we connected our 85 litre portable fridge to the dual battery system. We partly filled it with empty water bottles, to help the fridge maintain its setpoint temperature of 3°C.
Using the truck’s dual battery system allowed us to monitor input current and voltage from the Dometic solar panels, and whether it was keeping up with the system demands. Here’s the results.

A few notes about the test:

We laid the panels as flat as the stands allow – around 15° from horizontal. I faced the panels towards the sun, but only moved them a few times each day. This simulates what you’d typically do when camping. The fridge drew 6-7A and was running for about 20 minutes every hour.
The panels easily kept the battery charged.

The outcome?

The solar panel easily kept up with the demands of our 85 litre fridge on a very hot day. As with any monocrystalline panel, output decreased dramatically when it was in partial or dappled shade.
What’s impressive is the final reading shown above. The solar panel was pumping out 121W, bang on its rated output of 120W @ 25°C. And the panel wasn’t facing perpendicular to the sun. It was angled both horizontally and vertically.
Thankfully, Dometic’s claim of 120W is actually achievable in real-world testing.
We left the test running for four days. By the end of every day, the Lithium battery was fully charged.

Any Downsides?

We’ve already mentioned the battery temperature sensor cable… it’s too short to be of much use. However you’re unlikely to use it anyway, given it needs to be taped to the side of the battery. Even with a longer sensor cable, it would be a pain when moving the panel to chase the sun.One other comment… the portable panel stands can be fiddly. They have support arms which slip into slots on the legs. But when you lift the panel, the feet drop away, dis-engaging the support arms.

Once you know about it, this is easily fixed by folding the legs away before moving the panel. It’s only a minor thing and something we’d happily work around, given how well the Dometic portable solar panel performs.
While we’re talking about support legs. This panel copped continual severe winds from the side and rear… well over 50km/h and gusting much higher. However, the panel never looked like blowing over. It’s a solid unit.

An All-Around Performer

Dometic has created a practical and convenient portable solar panel. It’s easy to set up, folds away into a small footprint, and can be easily transported in its carry bag.

And most importantly, it delivers on its promised output.
The PS120A is a quality bit of gear… one we’ll be using for a long time to come.  If you’d like to get your hands on a Dometic PS120A portable solar panel for camping, then go here. P.S. You can follow Andrew and Peta’s outback travel adventures via their website and on Facebook, YouTube and Pinterest.