From the Tech Team | Solar Panel Efficiency

Posted February 23, 2021

Today, our Sr. Product Manager, Chi Woodruff, takes a look at an 18.5V 160-watt solar panel and the effect that the amount of sunlight reaching the panel has on its output. Watch the full video to learn more.


Hi, my name is Chi, I'm a product manager with RELiON battery. In this week's tech team video, we're going to take a look at solar panel efficiency.

In previous articles, we've covered adding solar panels to your RV or camping setup and you can find links to those articles that cover sizing your battery bank and solar panels in the comments section below but this week we wanted to review panel performance in more detail.

Solar is commonly available in 100-300 watt panels and when you look at spec sheets they always show ratings at maximum efficiency in ideal conditions. Realistically the temperature, weather, and time of day all affect how much power solar panels can generate. Also because the sun rides lower in the sky during winter months solar panels generally produce 30-50% less energy December through March compared to warmer summer months. All of these are very important factors to understand not only when considering adding solar but also ensuring that your system is performing as it should.

You'll get about 30 amps of power for every 100 watts of solar panels you have and you can use this as a general guideline when shopping for panels. Today we're going to take a look at an 18.5V 160-watt panel and the effect that the amount of sunlight reaching the panel has on its output. Our 18.5V 160-watt panel generates 8.6 amps which over about six hours of usable sunlight equate to 51 amp-hours. This means in perfect conditions you would be able to replace about 70% of the capacity of our solar charge-enabled Outlaw portable power station. BUT there's a caveat to perfect conditions. To demonstrate we have two cameras set up to show a multimeter and the angle of our solar panel facing the sun.

We begin with the solar panel tilted away from the sun in indirect light and you can see the multimeter displays the panel is outputting just under 1 amp of current. As we tilt the panel to an angle slightly towards the sun the amperage increases to just under 6 amps. Now as we tilt the panel to directly face the sun the amperage increases to the full output of the panel. The ability to keep your solar panel in direct sunlight has a major effect on your ability to recharge your batteries.

In conclusion, when considering adding solar be sure to keep the factors we discussed in mind, they have a major effect on your system's ability to meet your power requirements. We hope this video has been informative and if you have any questions please don't hesitate to call, email, or reach out to us on social media. Thanks for watching!

Photo by Campendium