Is your solar panel lying to you?

Most people know what a solar panel is and what it does. And while they might not understand the
inner workings of how a panel produces electrical energy, they know that the higher the power
output, generally the better it is for their 4WD or campervan. This is especially true when paired
with reliable 4WD batteries or campervan batteries, ensuring consistent power supply for off-grid
adventures.

Unfortunately, many unscrupulous vendors are well aware that customers are looking for high-power solar panel, but they also know that only a very small percentage of buyers will actually test the power output themselves. Because of this, some of these vendors take advantage of the situation by listing panels that don’t meet their advertised specifications. If you take a look on eBay, you’ll find dozens of listings for these kinds of panels. It’s a bit of a wild west out there, and it’s important to be cautious and do your homework to avoid falling for misleading claims.”

The Reality of Solar Panel Efficiency

Apparently, this panel has a size of 975*560mm and can be had for less than $120 including shipping.
Bargain, right?

Well, perhaps not quite. According to Clean Energy Reviews, the highest efficiency panel is the
SunPower Maxeon 6 440W with an efficiency of 22.8% (measured at an output of 1000W/m² ).
Taking the non-descript eBay solar panel’s claimed power output at face value, we can calculate the
efficiency using the following formula.

Electrical power out is easy, that’s 300W. We know that solar radiation is 1000W/m² but to convert
it to a power, we’ve got to get rid of the area term by multiplying it by its area.
So we get 52.2% efficiency! This is close to two and a half times the efficiency of the most efficient panel, so obviously something is not right.

The issue is of course that the 300W is just false advertising. They will be an actual 100W panels at
most.

It’s very difficult for the average user to discern what panel rating is real and what panel rating is
made up, so we have created an easy tool that will tell you if your panel rating is likely correct or just
completely made up:

There is fortunately one practical thing you can do (other than using the calculator above), and that’s to buy a high-quality residential solar panel. Click here to choose.

Residential solar panel have to be accredited by the CEC (Clean Energy Council) in order to be
eligible for RECs (Renewable Energy Certificates). Because of this, vendors can’t just make up the
power ratings like they can for unregulated panels. So if you buy a 300W residential panel, it will be
a lot bigger and heavier than the falsely advertised panel, but it will also be capable of outputting
300W of power under the right circumstances!