Solar panel comparison

Solar panel comparison

Australia really is the lucky country when it comes to sunshine – we have it by the bucketload.

With that in mind, it makes sense to capture this free energy and use it to power our campsite. 12-volt batteries which, in turn, run our appliances – lights, fridges, radios and all the other mod cons that campers pile into their vehicles these days – are powered via the photovoltaic process, which is a fancy way of saying solar power. Rather than delve too deeply into this highly technical process, we’ll set up our panels and let the results speak for themselves.

Solar isn’t exactly a new process; although, given the latest advances in technology, there are a few new products being used to capture the sun’s power. 4X4 Australia has been provided with the latest and greatest offerings from two of Australia’s major hitters in camping solar technology, – Redarc and Projecta – for testing and comparison.

Multiple weather scenarios were tested – full sun, partial shade, half sun, indirect sun, cloudy conditions – as well as the differences between various crystals with similar-sized wattage output, including polycrystalline, monocrystalline and amorphous panels.

Each company was asked to provide 120-watt panels to allow us to directly compare technologies and differing crystal types. There were small differences between wattage to take into account, but we’ve busted out the old calculator and done the maths in order to compare apples with apples and show the amps per watt each panel produces, as well as the raw results.

THE PANELS

Projecta has two 120-watt panel types: a folding monocrystalline kit (RRP: $699.00) and a bi-fold (RRP: $499.00) that has recently been changed from poly to monocrystalline technology.

Project multi-fold 120 wattStability is a concern with Projecta’s multi-fold panels.

Projecta's bi foldProjecta’s bi-fold panels are the cheapest options.

Redarc provided a 112-watt amorphous cell solar blanket (RRP: $2295.00), a 115-watt SunPower (monocrystalline) solar blanket (RRP: $1199.00), a pair of 20-amp solar regulators (sold separately at RRP: $145.00), plus a pair of 10-metre Anderson to Anderson cables (sold separately at RRP: $135.00). Despite being slightly smaller in rated wattage, it’s the closest we could get to compare with the 120-watt panels in order for a fair comparison test.

Redarc red blanket 112 wattRedarc’s red blanket puts quite a dent into the hip pocket. 

Redarc black blanket -115-wattRedarc’s black blanket was inefficient when it was half-covered.

Redarc solar regulator

To get a polycrystalline panel into the show, we’ve sourced an 80-watt Projecta unit (RRP: $399.00). This will help show the differences in physical size and power outputs. Again, our calculations will help even out the different panel sizes for a fair comparison.

Projecta bi-fold 80 wattThe Projecta 80-watt was the only polycrystalline panel. 

PANEL STATS

In order to test how each panel performed when not pointed directly at the sun or in partial shade, we placed cardboard over half its surface (which simulated dappled light with a 50 per cent coverage) and recorded the output.

The Redarc panel was the stand out for all the wrong reasons when the 115-watt SunPower black blanket (monocrystalline) recorded an almost total loss of amps when half covered by the cardboard – down to 0.24. We tested it by covering one panel (6.14 amps), two panels (5.38 amps) and three panels (1.85 amps). Other panels lost half the amps generated as predicted, which was acceptable (from approximately 7.0 amps down to 3.5 amps).

  MODEL CELL TYPE  AMPS PANEL
POINTING DIRECT
AT SUN (AMPS PER WATT)
AMPS PANEL HALF
COVERED AND DIRECT AT SUN
(AMPS PER WATT) 
AMPS PANEL LYING
FLAT ON GROUND,
INDIRECT SUNLIGHT (AMPS PER WATT)
1 Projecta 120-watt Bi-fold Monocrystalline 6.85 (0.057) 3.41 (0.028) 5.18 (0.043)
2 Projecta 120-watt multi-fold Monocrystalline 7.77 (0.065) 3.85 (0.032) 5.95 (0.050)
3 Redarc 115-watt sunpower black blanket Monocrystalline 6.20 (0.054) 0.24 (0.002) 4.71 (0.041)
4 Redarc 112-watt red blanket Monocrystalline 6.74 (0.060) 3.4 (0.030) 5.85 (0.052)
5 Projecta 80 watt  bi-fold Monocrystalline 4.96 (0.062) 2.49 (0.031) 4.27 (0.053)

Solar panels

PROS AND CONS

Each panel type and configuration has its positives and negatives (if you’ll pardon the pun). We initially had difficulty with the blanket panels as there was no way to prop them, so they faced the sun on their own. Luckily, through a combination of ingenuity and luck, we came up with our own rig with a few saw horses and lengths of timber – not exactly what you’d take camping but good enough for our comparison test. Draping the blankets over the roof of a tent or hanging them from your 4x4 with some pegs at the bottom is the proper way to use them, and they pack away nicely, saving space and weight in crowded vehicles.

Within the blanket range you’ve also got the option of monocrystalline or amorphous technology. The monocrystalline material is much smaller in area, however it produces similar amperage as the amorphous. The Redarc wiring and solar regulator kits (purchased separately) are top class in quality and ensure maximum potential power delivery via the long, thick, durable wiring that is connected via 50-amp Anderson plugs.

Whilst being the cheapest option, the hard-framed, bi-fold solar panels offer the least travel-friendly design. They’re larger and heavier than the other types but at least come in a padded bag which saves on wear and tear for both the panels and your pride and joy. They are convenient, however, with flip-down legs to enable direct placement towards the sun. The panels also have the wiring and solar regulator built in, which results in them typically being the most common type on the market.

The multi-folding Projecta panel system, while not quite as compact as the Redarc blankets, still pack away to a very useable and convenient travelling size with soft edges to prevent them from damaging your 4x4. They come complete with metal stands to prop them up towards the sun, or can be laid over the bonnet or roof of a 4x4 or tent which makes them more user-friendly. An improved leg design that doesn’t sink into soft surfaces (like sand) would be a bonus, though. The solar controller and wiring is all part of the initial outlay and built into a pocket in the panel’s cover.

Solar panels against log

SIZE MATTERS

While it’s always nice to have the biggest and best, knowing what size of panel you need may save you storage space and a few bucks.

Let’s assume our 120-watt panels are filling up the battery at about 5.0 amps per hour. Most fridges use (roughly) 2.5 amps per hour from a 12-volt battery. Whilst this leaves a lot of amps, factor in cloudy days, short days and long nights, dirty panels, other appliances and inherent losses of amperage and you’ll have a rough guide as to which size panel to choose for your needs.

Our advice would be to choose the next size up to make sure it all works as planned – too much power is never enough, especially when you start adding more and more gear!

Catching rays

DAY TEST

WE set up all five solar panels at the same time, and all charged a single battery which was powering four fridges.

Why four fridges? Initially, we tried this test with one fridge, then three, but the input power of the five solar panels was far higher than the outgoing power drawn from the fridge, and each solar panel took turns powering off. This proved that the solar regulators were preventing the battery from being overcharged, which could have potentially damaged it.

This is why it’s important to use a solar regulator, and ensure that panels charge a battery and not an appliance directly. So, combined with all those regulators, we managed to prevent our 120-amp Century deep-cycle battery from cooking itself.

The thermostat in each of the fridges was set to ‘freeze’ in order to use as much battery power as possible, ensuring a constant drain on the battery and allowing us to measure total input amps over a set period of time.

Each panel was propped up, however, instead of following the sun’s path. We left the panels in place throughout the day.

The first three hours and 45 minutes were pure sunlight, followed by a couple of hours of partial and full cloud. While not ideal for maximum charging, it did show the differences in power generation and proved that solar panels work in cloudy conditions, albeit at a much reduced rate.

The panels produced approximately 20 to 25 amps each. A camping fridge would draw an average of approximately 2.5 amps per hour. Add in camp lighting and whatever other electronics you have and suddenly that 25 amp figure isn’t so impressive!

Project bi-fold products

THE VERICT

The larger the wattage panel, the more power you’ll produce. However, our testing found that no solar panel stood out from the pack.

With regards to amps per watt, the panels are all pretty similar in their power production: about 0.6 amps per watt, give or take a bit. Of course, out on the road there are countless variables that will affect this output including shade, pointing directly at the sun, dirty panels, hours of sunlight, heat build-up... the list goes on, so our figures should be used as a guide only.

If it was left to us, however, we’d swing more towards the Projecta kits (there are 80-, 120- and 150-watt versions available), but we’d also spend a little time doing some DIY work on the panel’s legs to improve their stability and performance on soft surfaces.

MODEL CELL TYPE  Time
(full sun)
Total amp hours
(avg amps per hour)
Cumulative time
(study) 
Total amp hours
(avg amps per hour)
Projecta 120-watt Bi-fold  Monocrystalline 3 H 45 min

23.95
(6.39)

5 H 15 min

25.84
(4.92)

Projecta 120-watt multi-fold Monocrystalline 3 H 45 min

23.95
(6.29)

5 H 15 min

25.29
(4.82)

Redarc 115-watt sunpower black blanket Monocrystalline 3 H 45 min 19.94
(5.32) 
5 H 15 min 21.33
(4.06)
Redarc 112-watt red blanket Monocrystalline 3 H 45 min 19.52
(5.21) 
5 H 15 min 20.93
(3.99) 
Projecta 80-watt  bi-fold Monocrystalline 3 H 45 min 15.90
(4.24) 
5 H 15 min 18.22
(3.47) 

Want to know more? We filmed the test to see which panel was the best. Watch the full solar panel comparison video review.

Get the latest info on all things 4X4 Australia by signing up to our newsletter.