Which Solar Panels Perform Best? – We tested them in the Real World

Have you ever wondered what hard solar panel to buy and which panel performs best? In this video, after six months of rigorous testing, we show you the hard facts. In March of this year, we installed 32 panels on the roof of a garage. Since this is a test, we wanted the comparisons as accurate as possible and a similar power and voltage for each panel. The top row of eight panels closest to the house are Victron Energy 360 watt, 24 volt mono panels. The second row of eight panels are Victron Energy, 330 watts and 24 volt, poly panels. The third row of 8 non-Victron panels are 330 watts, 24 volts PERC. As you can see the panel is split in two, both with poly and mono panels, and they are said to have a higher shade tolerance and that the power is 24% higher. The last row in this test are non-Victron split cell panels. These 305 watt, 24 volt panels have a similar technology like the PERC but have split cells. The default cell is for a split-cell panel divided in two and by bus bars, thus the effectiveness would be increased, reduce hotspots and the voltage and temperature are reduced. Each set of panels is wired in its own two parallel sets of four panels in series.

Each series of panels goes back to its own MPPT 250 | 70 charge controller and we have made sure the cable length is the same so that the resistance remains the same. All panels face south with an angle of 25 degrees. They have been professionally installed by a Victron installer on a hard aluminum frame. There is no shadow on the panels and throughout the test the panels became regular washed and cleaned to maximum performance to obtain. All four control data is sent via the VE.CAN to a Cerbo GX and then online to VRM. The system was installed on top of a house with a family of four and an electric car. Three Multiplus of 48 volts, 5,000 VA, 70 amps are connected to create three-phase power in the house.

The temperature of a solar panel can significantly affect its effectiveness, so we also installed sensors for solar radiation, temperature and wind speed. There are four external modules. A solar radiation sensor, this measures the radiation from the sun at the test site. There is an ambient temperature sensor which must be placed in the shade. There is a cell temperature sensor on the other side of the solar radiation sensor. Finally, we have a wind speed sensor. Via an RS485 USB interface all weather data can be connected to the Cerbo GX and charged to VRM via the internet. Solar panels love the cold and you will often notice that they work best on cold winter mornings due to the low temperature.

All four types of panels were placed on an open frame to allow air to circulate around and behind so that they stay cool and thus work at their best. So the data. At the top of the victronenergy.com website you will find a new button "Field Test". If you click on it, it will show how the four types of panels perform. Despite the fact that some panels have a greater total wattage, so as to be accurate possible, the wattage tested is mathematical set to 2,500 watts and calculated accordingly. The data is charged every few seconds and within the left panel do you see the outside temperature, the temperature measured with the thermostat who is in the shade, the wind speed and solar radiation. You also see the GPS coordinates from the test site in Romania. At the time of the shooting the mono panels generate 1,320 watts of solar energy.

The split-cell panels are 1,286 watts. Poly generate 1,251 watts and PERC generate 1,308 watts. The structure of each panel type reacts differently to weather conditions, so the yield of the solar panel at the bottom each type of solar panel is the deciding factor. As you can see in our realistic test, currently all panels are quite similar in output on this installation site. This is likely to change significantly during the cold winter months, so keep an eye on the results. Our test did not include price or availability, but it does give you a realistic picture that you will hopefully find useful..

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