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Anker Solar Charger

Anker Solar Charger

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While power banks have already become the norm when it comes to extending the life of portable devices, power banks with solar panels are still beginning to boom.  However, many users are unfamiliar with the many benefits linked to solar chargers, as well as limitations, and hesitate to choose them over conventional power banks.  For this reason,  here at Power Bank Expert, we’ll break down the pros and cons of the Anker 21W 2-Port USB Solar Charger so that you can determine if it’s the right fit for you.

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Capacity & Charging speed

The first thing you need to know about the Anker 21W 2-Port USB Solar Charger is that it does not have a battery pack. Therefore, it cannot be considered a power bank because what it does is to transfer the power coming from sunlight to the devices plugged into the unit. For these reasons, you won’t see the advertised capacity expressed in mAh as in proper power banks.

Moreover, there is a bit of controversy as to exactly how much efficiency you can expect from solar devices like this one. A product that claims 21W can do close to this under near-perfect conditions, but the reality is, even with Anker’s 21.5-23.5% efficiency rating on their cells, you can’t expect more than 13-14W output at any point.

Additionally, sunlight is required to charge the solar panels and the devices, and in case you’re wondering, there is no input port given that it doesn’t have a battery pack. This can be a double-edged sword because the charging speed is entirely reliant on the sun, which means that on cloudy days, the performance of the charger will decrease. On the other hand, you won’t need to wait for a long time for the unit “to recharge”; it’ll be ready to charge your devices by leaving it under the sunlight.

With 2 USB ports of 5V/2.4A, the Anker 21W 2-Port USB Solar Charger can offer a maximum of 3 amps output at any one time. To their credit, they offer PowerIQ technology, and pretty fast charge speeds to your device of choice. It is fast enough to charge a 6000 mAh battery from 0 to 100% in less than 4 hours. Besides, we found that the Anker 21W 2-Port USB Solar Charger works well under hot, humid conditions and can simultaneously charge 2 smartphones at once splitting the total output of 3A.

Do be careful though; the Anker 21W 2-Port USB Solar Charger will not charge the following devices: iPod nano, iPod Classic, iPod Shuffle, HP TouchPad, and Asus tablets. Lastly, in some cases, it isn’t reliably compatible with some higher-capacity power banks and portable chargers.

Look and feel

The Anker 21W 2-Port USB Solar Charger has a very simple and functional design. It consists of three solar panels encased and separated by a meshy canvas, which allows them to be folded into themselves nicely. There are two stainless steel eye holes on each corner-end of the product and two more on the third panel down. These are great for hanging the charger from a tent, a tree, a backpack – anywhere really, be creative!

Because it is not a power bank, it doesn’t come with functional components such as a power button, LED indicator, or any other bonus features. It comes, however, with a USB port hub where you plug the devices you wish to charge. This is covered by a protective pouch and contains a red light that indicates when the sunlight is charging the solar panels.

On the other hand, straight out of the box, the Anker Solar Charger Power Bank comes with an Anker 3ft Micro USB cable, a welcome guide, and an 18-month warranty.

Durability & Construction

A product like this is begging to be taken camping, so it needs to be durable. Just as important, it needs to work and be consistent. In some cases, the Anker 21W 2-Port USB Solar Charger does not work so well because a shadow or a passing cloud seriously affects the output of the device, and it would take a while for it to get going again.

On the plus side, when exposed to enough sunlight, it works great. This is because the solar panels are high-quality and protected by industrial-strength PET polymer. Additionally, the polyester canvas is rugged, durable, and water-resistant, which protects the USB Port Hub and is indispensable for outdoor conditions. Stainless steel was used to make the eye hole rings, so they are really durable.

Regarding electronic protection, it also comes with Anker’s standard short circuit and surge protection technology to prevent your devices from damaging. Like any solar charger, however, we recommend not leaving it out in the rain. Not only chances are you aren’t getting much charge with such weather, but there’s also a likelihood of damaging its electronic components. If this is the case, you won’t be backed by its 18-month warranty or its 30-day return policy.


We love the design of the Anker 21W 2-Port USB Solar Charger, which can be described best as functional. At 11.1 x 6.3 x 1.1 inches, it’s a little bigger than you might imagine from the pictures, but it folds away beautifully and is quite thin too.

With a total weight of 14.7 ounces, it is certainly not the heaviest nor the lightest of its kind. The truth is that it is not intended to be handheld, but it’s still very easy to carry around with you and is worth the extra bulk in your backpack or bag. The fact that it’s flexible and extremely compact makes it a great addition to any outdoor activity.



Excellent charging technology

2 USB output ports

Fast speed

Highly portable and flexible



Always need a source of light to work

Poor performance on cloudy days

Samll pouch to store accsessories

Final Thoughts

Portable solar chargers are becoming as popular as they are inconsistent. The Anker 21W 2-Port USB Solar Charger does a good job of squashing many concerns that other manufacturers may be responsible for spreading. All in all,  high-quality cells that offer a fast speed coupled with clever design choices make this one of the best portable solar chargers on the market.

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