By Aimii | 26 November 2021 | 0 Comments
How Much Power Does A Solar Panel Produce In A Day?
How much power can be generated in a day for RV solar panels? This is one of the most concerning issues for many RV camping enthusiasts. Before that, let's first understand the main factors that affect the power efficiency of solar panels.
What affects the power efficiency of RV solar panels?
First, the illumination angle. We know that the sun rises in the east and sets in the west, so the different illumination angles generate different solar power efficiency. And different latitudes and longitude, and seasons will produce corresponding different illumination angles.
Second, the light intensity. One RV solar panel can generate different output power under different light intensities. For example, the max output power of a solar panel is about 101 watts under the light intensity of 1200 lux, while the max output power under a light intensity of 200 lux is only about 17 watts, a difference of more than 5 times. The greater the light intensity, the greater the working current of the RV solar panels.
Thirdly, the shadow occlusion. If the solar panels were blocked by some devices like the air conditioners' external units and satellite TVs, its power efficiency will definitely be reduced. So it must be avoided during the RV solar panels installation. We made a test that shaded a portable 100w solar panel in 1/2 horizontal and 1/2 vertical parts and found that the horizontal shading has a more serious impact than vertical shading. Under the 1/2 horizontal shading, the measured output current of the solar panel was 0.01A, almost no current output.
In addition, dust and debris on the solar panel will also affect its power efficiency.
How much power can a solar panel generate in a day?
Based on the above factors, it is actually difficult to give an absolutely definite number. But we can make a theoretical calculation: a 100-watt solar panel can theoretically emit 100W*6H=600WH under standard lighting conditions (light intensity of 1000W per square meter) and an average sunshine duration of 6 hours. 600WH is equal to 0.6KWH. That means theoretically it can generate 0.6KWH power.
After all, there is a gap between theory and reality. This figure must be discounted in real scenarios. If we calculate various losses such as line loss, light angle, light intensity, etc., we calculate it at a conversion rate of 70%, a 100-watt solar panel can generate about 0.6*70% = 0.42 KWh per day. This hypothesis is under this ideal condition: the duration of light can be up to 4-5 hours, the outdoor temperature is 25°C, the sunlight is shining on the solar panel vertically at 90°, and the MPPT controller is used on the vans.
Solar panels of different brands may output different solar efficiency. You can also find the solar panel reviews on Youtube to learn about the real test and use experience. For example, XTAR SP100 is rated as a 100w portable solar panel, but some Youtubers found it output 110w in real tests, much higher than you thought. Here is an infographic about the real output solar power comparison of solar panels from XTAR, Renogy, and Rockpals.
You may also be concerned about whether you can use the device when it is under the charging of a solar panel. There is no problem in theory, but you need to pay attention that the power of the load and loss should be matched. For example, the load power is 100 watts, the solar power is 200 watts, plus the 40 - 50% loss, it can basically ensure normal operation. But if the load power is 100 watts, while the solar power is also 100 watts, and plus the normal loss, then the normal operation cannot be guaranteed. You may need a power station or power battery to balance it.
Solar panels also work on cloudy days, even though it is not as effective as on a sunny day. They can generate about 10 - 25% of their normal power output on a cloudy day. For a 100 watt solar panel, that is 6 amp-hours per day in cloudy conditions.
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