Why power banks with solar cells are total nonsense ...

Testing power banks is one of my favorite things to do when I look at the amount of posts about power banks on my blog. And yes, these small and large energy stores are fascinating and very practical in everyday life.

A special branch of these devices are so-called Solar power bankswhich usually have solar cells built into a surface and thus suggest independence from the power grid.

Test with Anker PowerCore Solar 10000

To see how well solar power banks are doing in the test, I took them from Anker PowerCore Solar 10000 can be sent. An outdoor power bank with a rubberized housing, flashlight function and two USB-A outputs. The model came out in autumn 2020 - at a time when there were still a few days of sunshine that I used for testing.

With 10.000 mAh, the power bank is not even one of the largest, because there are certainly models that offer more than twice the capacity with 26.800 mAh. The problem with this is that the high capacity also has to be filled. But more on that in a moment ...

Not enough solar cells per watt hour

There are no problems whatsoever when using the solar power banks, because the devices deliver just as much electricity as the power banks, which are only charged via a cable. Charging by cable is also unproblematic, because the Anker PowerCore 10000 is filled again in a few hours.

However, if you want to fill the empty power bank with solar energy, you will quickly notice that this type of power bank has a fault in the system: The solar cell delivers so little electricity that you would have to wait many days until the device is filled again, even with high levels of solar radiation.

The bottom line is that the solar power banks all have the problem that they have too small an area with solar cells in relation to the watt hours that have to be charged with them.

For this reason, there are often reviews like this:

As a power bank top, solar flop.

Anker typically good power bank but the solar function is useless. 1 week in the car (free parking space), 5 days in daylight and it hardly helped.

Charging for a month does not bring the battery level to 25 percent

I have had a very similar experience as the customer above. I can even top it, because I had forgotten the power bank in front of the window on the windowsill (south side) and only brought it back in after more than a month. The result: The power bank showed only one glowing LED out of 4 status LEDs. So it had a "fill level" of a maximum of 25%.

But you can definitely certify that the power bank is suitable for outdoor use, because it has been exposed to sun, rain and wind for a long time and has not suffered any damage.

Solar power bank models with 4 times the solar area

At Amazon you can now find solar power banks that have foldable solar cells. This gives you four times the area of ​​solar cells when you compare them with conventional solar power banks.

On offer here are these two models from GOODaaa and elzle:

• GOODaaa solar power bank with 25.000 mAh: 1x Micro-USB input, 1x Micro-USB output, 2x USB A output, flashlight function
• elzle solar power bank with 26.800 mAh: 1x Micro-USB input, 2x USB-C output, flashlight function

Is this the solution to the power bank charging problem? Not from my point of view. Because if I need a month to get a maximum of 25 percent charge, then I would still need at least a month to fully charge the power bank, even with a solar area four times as large.

And consider that I'm talking about a 10.000 mAh power bank. The models with over 25.000 mAh would charge significantly longer.

• Recommended reading: SunnyBAG solar backpack: on the go with 7 watts of solar power
• Recommended reading: Test: RAVPower RP-PB003 power bank with solar panel and flashlight

The better alternative: foldable solar panels

When researching practicable ways to generate solar power for iPad, iPhone and MacBook on the go, I'm on "Serious" solar panels encountered. On the one hand, these offer USB connections to draw power directly, but on the other hand they also have a DC voltage output to "mobile battery sockets" to supply.

One model that I liked here is this Eco-Worthy 120W solar panel. You can do this, for example, with the Poweroak power station with 500 Wh connect, which offers two socket outlets that output a real sine wave.

In terms of the area that is used to generate electricity, we are significantly larger here than with the solar power banks and are included with the EcoWorthy model, which I have selected about 1 square meter. In full sunlight and in perfect alignment, it is said to be able to deliver 120 watts, but under German conditions I would rather carefully calculate with half or a third.

With a third we still get 40 watts, which is easily enough to charge an M1 MacBook Pro. It is definitely enough for iPad and iPhone. As a rule, however, these panels are coupled with a battery, which also functions as a mobile socket. This gives you the best possible comfort when camping. However, due to its size and weight, the solution is likely to be unsuitable for hiking.

But the solar panel is also significantly more expensive (almost 150 EUR), weighs more (approx. 4 kg) and takes up more space when setting up and transporting it.

Need a smaller solution? Solar panels and power bank separated

If you need the same system in a smaller version, you can go to my subpage "Solar power bank" look. There I presented smaller solar panels, which you can also take with you on hikes. With these you get halfway the power with which you can charge a standard power bank. Still slow, but faster than with the power bank solar cells.

My conclusion: Instead of solar it is better to use a “pure” power bank

My tip is to do without the solar charging function on the power banks and instead use a good power bank without solar. If you are actually on the road for a longer period of time, the solar function does not help anyway and you have to rely on charging via cable.

It is better to get a larger power bank that can only be charged by cable and has more capacity for the same size.

If you are looking for a solar power bank as a solution for a caravan or mobile home, you should perhaps buy the larger solar panels with a decent converter and battery so that you have enough power for all devices.

Jen Kleinholz( Founder & Sir Apfelot )

Jens has been running the blog since 2012. He acts as Sir Apfelot for his readers and helps them with technical problems. In his spare time he rides electric unicycles, takes photos (preferably with the iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions to current bugs.