Conclusions: A solar mobile phone’s performance is affected by lifestyle

After four months, our solar charging project has come to an end. In that time we’ve collected huge amounts of invaluable data from places as far apart as the Arctic and Kenya. We already knew that for solar charging to be useful it needed to be able to power a phone or at least increase its operational time. Fortunately, the newest phones have such low stand by power consumption, solar power has a better chance than ever to do just that. But, how did things pan out in reality?

Sailing the Baltic with Petteri

Sailing the Baltic, Petteri had little time to use his phone. Consequently, he was able to fully power his phone from the sun during the entire voyage. In fact, he even ended topping up his battery.

One key reason for this was that Petteri never moved his solar powered mobile prototype Lokki, from the deck of the boat. This meant it was almost constantly facing the sun.

Listening to Kenyan radio with Amos

Based in Kenya, Amos, managed to collect more solar energy than anybody else. However, he was also the most hardcore user and often used all his harvested energy to listen to the radio or to make calls.

Amos success harvesting was not just a result of the Kenyan climate, but because his job as a security guard meant he was often stationary. As he reported on June 30th “I put my phone out, placing it on a pillar next to the gate where I was working ”.

Camping in Sweden with Aino

When Aino went to her scout Jamboree in Sweden, she gained about 15% battery life during the ten-day camp. If she was lucky, that might be just enough to keep the phone powered up for the entire event, which as Aino said, was bonus.


Being part of a scout camp meant that Aino was on the move most of the day, which made exposing Lokki to sunlight a lot more challenging.  However, Aino wasn’t willing to wear her phone around her neck as she was concerned it made her look unstylish.

Living in the Arctic with Ilkka

Starting from the 26th June, Ilkka only charged his Lokki using only solar energy until the phone eventually ran out of power on July 18th. How did he do so well? For a start, Ilkka was able to keep Lokki outdoors while building his house, which harvested a great deal of power during the long Arctic summer days, which have a potential daily harvesting window of 19 hours.

What’s more, Ilkka was one of two testers, along with Esa, who carried Lokki on their body, strapped to a backpack or around their neck while on move. Ilkka even took his Lokki with him to “inspect the success of birds nesting in covered woodland”. During these days, Ilkka was able to harvest 15mAh, about 10% of the energy compared to the times Lokki was hanging from his house. This suggests that to stay connected while treking, you need to harvest energy for much longer, in Ilkka’s case ten times longer, than when stationary.

Treking in the Arctic with Esa

As an expedition leader, Esa was the most energetic of our testers. When hiking Esa was able to get some sunlight for long hours, but the very fragmentary, northern sun shines low, which means there are countless shadows. Consequently, it was no surprise then that Esa’s battery ran out.

Nor was it a big surprise when the phone was exposed to the weather, it sometimes got wet from rain. Both Ilkka and Esa found a waterproof and durable carry solution to be essential. As Esa pointed out, harvesting solar energy while carrying the phone is also challenging because we rather find a shadow and at least turn our face out of the sun while trekking. No wonder then the best harvests were when Lokki was stationary in one place in the sun.

Our test users proved beyond doubt that a low power mobile phone can stay functioning for long periods of time on solar energy. However, they also proved that your lifestyle and how you use a solar powered phone is as important as the environment, the weather and the time of year. Does this discovery surprise you? Or any of the other findings? If so, we’d love to hear your thoughts below.

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3 Responses to Conclusions: A solar mobile phone’s performance is affected by lifestyle

  1. Paul says:

    Fantastic article and probably the most in depth we have found.

    As suppliers of solar chargers (mobile and fixed) it is great to see a real, varied field trial that supports what we know, they really work so people wake up and meet you own energy needs.

    The lifespan on these products is also very good (longer than you will keep your phone by far) so the costs should be considered over few years.

    Thanks for a comprehensive study.

    • Joel says:

      Thanks for sharing your thoughts, Paul. Glad to hear you’ve found the field trial and blog useful. We hope this has enlightened people to the possibilities and restrictions of solar charging.

      We’ll post one article discussing our finding. We hope you find that useful, too.

  2. A cell phone’s performance is definitely affected by a person’s lifestyle. Someone who listens to Pandora all day, for example, is definitely going to have a shorter battery life than someone who only uses it for infrequent phone calls.

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