Can I make my iPhone solar powered?

Solar chargers for smartphones in the CHIP test

Sun power for your cell phone

Viviane Osswald

What helps if the cell phone battery runs out on the go? Power banks. But they will also be empty at some point. The everlasting alternative are solar chargers. We tested various solar panels and solar power banks. Our test shows: If you want to get a reasonable amount of electricity on your excursion in nature, you prefer to use a solar panel. Unlike solar power banks, panels do not store electricity themselves, but they are significantly larger and charge USB devices more quickly. The most powerful solar panel took around three hours to fully charge a mid-range cell phone in the test. In addition, power banks heat up noticeably in the sun - this certainly does not have a positive effect on the durability of the battery.

advantages
Compact and portable
disadvantage
Extremely dependent on the weather

Battery empty in the countryside - what now?

Summer, the ideal time of year for all outdoor leisure activities. Whether on the festival site, the campsite or in the mountains: the nearest power socket is often a long way off. If the smartphone threatens to give up on the go, a portion of Sunpower-to-Go is a helpful method of supplying the cell phone with juice - especially in an emergency. But what are the real benefits of different solar chargers? We tested some interesting models. But one thing is certain: Not much is possible without direct sunlight.

Solar chargers in the test

We have tested all solar chargers in various test scenarios. We connect an empty RAV power bank with a capacity of 22,000 mAh to the USB port of the respective charger and use a USB tester to measure how much power (in watts) the charger can generate.
  • Test scenario one: The sun is shining, there is hardly a cloud in the sky. All solar chargers lie flat on the floor.
  • Test scenario two: Small clouds move in front of the sun. All solar chargers lie flat on the floor.
  • Test scenario three: The sun is shining, there is hardly a cloud in the sky. We aim the solar chargers towards the sun.
  • Test scenario four: The sun is shining, there is hardly a cloud in the sky. We're turning the solar chargers away from the sun.
In a second test run between 10:40 a.m. and 3 p.m. on the roof terrace of the CHIP editorial team, we connect a Huawei P8 Lite to a USB port each and check how long it takes for a few small ones in the blazing midday sun Cloud is fully charged.
Direct charging of smartphones is possible with all of the solar chargers we have tested. However, it makes sense to first charge a power bank as an intermediate buffer. This is because - unlike smartphones - they are satisfied with even small currents and do not interrupt the charging process when the radiation intensity is lower.

Test device number one: Anker PowerPort Solar 21W

With 21 watts, the Anker PowerPort Solar is the "largest" solar charger in our test. It consists of four elements, three of which each comprise a solar panel. The fourth acts as a pocket in which the two USB ports are housed. There is also space for your cell phone (or other devices) so that it does not have to lie in the blazing sun while it is being charged.
The workmanship is impeccable. According to the manufacturer, the panels are coated with PET polymer and sewn into polyester fabric. This allows the entire panel to be folded from 282 mm to a size of 160 mm. Since it only weighs about half a kilo, it can be easily stowed away and does not cause much additional effort on the excursion into nature. In addition, the material should be weatherproof. Nevertheless, Anker recommends not to expose the charger to too much moisture in order to protect the electronic components. With the help of the stainless steel eyelets, the Anker Power Port can be attached to the backpack or other objects.
Further technical data:
  • 21 watts
  • 670 x 282 x 5 mm unfolded
  • 282 x 160 x 28 mm folded
  • Compatible with Apple and Android smartphones, tablets, other USB charging devices (except iPod nano, iPod Calssic, HP TouchPad and Asus tablets)
  • 2 USB ports with up to 2.4 A per port, 3 A total
  • Available from around 60 euros

Anker PowerPort Solar 21W: measurement

With a flat orientation and bright sunshine around noon, we measured a maximum value of 10 W power. In the case of clouds, the Anker PowerPort generates only 1.5 W. If the solar charger is directed towards the sun, the power increases to just over 10 W. When directed towards the sun, it comes to 1 W.
In our test, the Anker PowerPort took about three hours from 10:40 a.m. to fully charge the Huawei P8 Lite with a 3,000 mAh battery. If the power was 4.4 W at the start of charging, it had dropped to 1.8 W at the end of charging.
Our measurements did not reach the maximum value of 21 W stated by Anker. Even with the best weather conditions and direct alignment, these 21 W are not made available to the devices to be charged. This is due to the loss in the voltage converter, which, depending on the intensity of the sun's radiation, regulates the voltage at the charging sockets in accordance with the USB specification. Anker offers a charging speed of up to 2.4 A per USB port or 3 A in total. At 5 V output voltage (standard for telephone devices) this corresponds to a maximum system power of 15 W.
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Test device number two: RAVPower 16W

On paper, the RAVPower cannot keep up with the Anker PowerPort with a maximum output of 16 watts, but how does it look in practice?
The solar charger also consists of four elements, one of which does not contain a solar panel, but serves as a bag for the devices to be charged. It is slightly smaller and lighter than the Anker PowerPort 21 W. The solar panel with hardened PET plastic surface is woven into a polyester housing and should also be weather-resistant. Here, too, there are eyelets to be able to attach it.
Further technical data:
  • 16 watts
  • 645 x 239 x 5 mm folded out
  • 239 x 160 x 20 mm folded
  • Compatible with Apple and Android smartphones, tablets, other USB charging devices (except iPod nano, iPod Calssic, HP TouchPad, LG G2 and Asus tablets)
  • 2 USB ports with up to 1 and 2 A per port, 3 A total
  • Available from around 50 euros

RAVPower 16W: measurement

In bright sunshine we measure a maximum power of 7.2 W, with clouds it is 0.7 W. When facing the sun, the power of the RAVPower of 7.7 W differs by 2.3 W from the Anker PowerPort. When facing the sun, the RAVPower does not have 1 W like the anchor, but only 0.6 W.
The Huawei P8 Lite was 90 percent charged after three hours on the roof terrace, the RAVPower generated an output of 4.2 W at the start of charging, which later fell to 3.6 W. An hour later, the phone was fully charged.

Test device number three: SunnyBAG Explorer +

The Austrian company SunnyBAG offers a combination of backpack and solar panel with the Explorer + (view on Amazon). A solar panel with six watts of power is attached to the front of the polyester backpack with a click fastener - you can remove it if you want. The device to be charged can be stored in a small pocket on the front. According to the manufacturer, the material should be weatherproof. The power backpack offers 15 liters of space and a 15.6-inch laptop compartment is integrated. The backpack is comfortable to carry thanks to the padded, approximately seven centimeter wide shoulder straps.
Further technical data:
  • 290 x 370 x 140 mm (panel)
  • Compatible with Apple and Android smartphones, MP3 players, navigation systems, outdoor & action cams, tablets, iPod, Kindle, game consoles
  • 1 USB port with 2.4 A
  • Available from 79 euros

SunnyBAG Explorer +: Measurement

In the test with bright sunshine and a flat orientation, the 6-watt solar cell managed to start charging at 3.8 W; in clouds, it was a bit poor at 0.5 W. Aligned to the sun, the backpack panel comes to 4.1 W. When facing the opposite way, it generates only 0.4 W.
Of course, it is also interesting how much the SunnyBAG Explorer + can do when you wear it. We did the practical test and measured the following values:
Position to the sun: 2 W
Position in the (tree) shade but to the sun: 0.2 W.
Position against the sun: 0.5 W.
Position rotated 90 ° away from the sun: 1 W

Revolt solar power banks with 20,000 and 11,000 mAh

And what about solar power banks? The practical thing is that they store the electricity generated directly. But are they really a reliable power source for on the go? We tested two Revolt solar power banks with capacities of 20,000 and 11,000 mAh.
The workmanship of both solar panels is good. An LED flashlight is integrated into the larger power bank; the smaller one comes with a camping light with 20 LEDs and bright 240 lumens.
Further technical data:
  • 20,000 and 11,000 mAh
  • 86 x 26 x 162 mm and 78 x 25 x 120 mm
  • Compatible with Apple and Android smartphones, tablets, other USB charging devices
  • 2 USB ports with up to 1 A per port, 2 A total
  • Micro-USB port for charging via power supply
  • 20,000 mAh power bank available from 50 euros
  • 11,000 mAh power bank available from 27 euros
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Revolt solar power banks with 20,000 and 11,000 mAh: measurement

The two solar power banks disappointed us in the test. We put both empty models in the blazing sun for a whole day. In the evening they were just 10 percent charged. The big problem with solar power banks is simply the size of the solar cell. It is simply too small to recharge the battery in a reasonable period of time. Also noticeable: the battery packs got very hot in the sun - that certainly does not have a positive effect on the durability. It pays to spend a little more money and grab a fold-out panel right away. Alternatively, you could charge the power bank in advance using the power supply so that it doesn't have to be completely empty from the sun. Together with additional solar energy, it still has the potential to become a handy power supplier in nature.
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Biolite Campstove: Camping stove with battery charging function

What can we actually do if it rains cats and dogs all day or if we run out of juice at night? There is another solution for these cases: The Biolite Campstove. It doesn't charge the cell phone with the sun, but with fire. In the test, the power output is low, but better than nothing in the middle of nowhere in bad weather.
A second version of the Biolite Campstove is already on the market. You will find the best offer in our price comparison.
Shop recommendation for Biolite CampStove 2 BL-CSFL2
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Solar chargers: All measurements (possibly more columns in desktop view)

-Anker PowerPort 21WRAVPower 16WSunnyBAG Explorer +

Flat - sun

10 W.

7.2 W

3.8 W.

Flat - clouds

1.5 W

0.7 W

0.5 W

Aligned to the sun - sun

10 W.

7.7 W

4.1 W

Away from sun - sun

1 w

0.6 W

0.4 W