Whether you’re hiking, on the beach or at the campsite: there isn’t always an outlet within reach. A solar backpack is the ideal way to still supply smartphones & co. with electricity. TECHBOOK presents the best models and reveals what is important.
Anyone who spends a lot of time outdoors probably knows the problem: you’re about to check your location on your cell phone when the battery is suddenly empty. Or the digital camera says goodbye to the most beautiful photo motif. If you have a solar backpack with you, you’ll be lucky – you can recharge electronic devices using solar energy. Whether you’re walking on the beach or hiking through the mountains: Where there’s sun, there’s also electricity with a solar backpack. But what makes a good backpack with a solar panel? And which models meet the criteria? TECHBOOK shows you the best solar backpacks and panels.
How does a solar backpack work?
A solar backpack has a photovoltaic panel on the front, which, like a solar system, converts the sun’s energy into usable electricity. This can be used to charge electronic devices on the go – independent of sockets and cables.
However, most solar backpacks do not have built-in storage for electricity. This means that you either have to draw off the energy directly, for example by connecting a smartphone to the panel. Or you can alternatively connect an external storage device such as a power bank in order to be able to use the solar power later. With some backpacks, a suitable power bank is included in the scope of delivery.
The best solar backpacks in comparison
In the following, TECHBOOK presents three solar backpacks and reveals what they can do and what advantages and disadvantages there are.
Sunnybag Explorer+
Manufacturer Sunnybag has specialized in solar backpacks and components such as power banks and panels and is currently leading the DACH market. The Sunnybag Explorer+, for example, is a model with a volume of 15 liters and a weight of one kilogram. Inside there are numerous extra compartments, for example for pens, glasses, laptops and tablets. On the side there are two more compartments for drinking bottles, umbrellas and more.
Practical: The solar cell is attached to the backpack with buckles. It can be easily removed so that the bag and solar panel can be used separately. A transparent compartment is attached to the back of the panel, in which mobile phones or a power bank can be accommodated. The USB-A plug is also placed there. A small lamp shows in three colors the amperage at which the solar module is currently generating electrical energy:
- Blue: over 0.8 amps (A)
- Green: over 0.5A
- Red: less than 0.5A
| Sunnybag Explorer+ | |
|---|---|
| Performance | 6 watts |
| efficiency | 22.4 percent |
| volume | 15 liters |
| Weight | 1 kilogram |
| features | Removable panel, many compartments (including for laptop and drinking bottles) |
Advantages:
- Panel and backpack can be used separately
- many different subjects
Disadvantages:
- no integrated power bank
Sunslice Zenith
The Zenith Solar Backpack from Sunslice has dimensions of 45 x 35 x 25 centimeters and holds around 39 liters – you can fit a lot in there. In addition to a bottle compartment on the side, there are two large main compartments. In the front compartment is the USB port that connects to the solar charger. There is also a direct USB output on the outside, so you can continue using the devices while they are charging. There are hidden pockets for valuables such as a wallet, ID or cash on the back of the backpack and on one of the shoulder straps. Ideal for travel: An elastic band on the back is ideal for attaching the backpack to a suitcase handle.
The solar cell is firmly sewn into this backpack, so it cannot be removed and used separately. Although it converts only 15 percent of the light energy consumed into solar power, the output is comparatively high at eight watts.
| Sunslice Zenith | |
|---|---|
| Performance | 8 watts |
| efficiency | 15 percent |
| volume | 39 liters |
| Weight | 1.1 kilograms |
| features | Many compartments (including for laptop and drinking bottles), waterproof |
Advantages:
- many different and hidden compartments
- large solar panel with high performance
- Inside and outside USB port for panel
Disadvantages:
- quite low efficiency
- Panel not removable
- no integrated power bank
Also interesting: The 7 best solar chargers in comparison
Estink
Rather unknown, but equally useful, is the solar backpack from Estink. This is a model with a capacity of 40 liters and many different compartments. The panel was sewn into the case and, according to the manufacturer, should be scratch and layer resistant. The bag was made of polyester or PVC and is waterproof, wear-resistant and is said to have high durability.
Since the bag is not sold in Germany, it has to be imported from abroad. Therefore delivery may take a little longer than usual. In any case, the backpack is suitable for cycling, hiking or camping without any problems. It is particularly practical that a power bank with a battery capacity of 10,000 mAh is integrated. The backpack is available in the colors gray and red.
| Estink | |
|---|---|
| Performance | 6.5 watts |
| efficiency | 20 percent |
| volume | 40 liters |
| Weight | 957 grams |
| features | Many compartments, waterproof |
Advantages:
- quite cheap
- Integrated power bank
- many different subjects
- large solar panel
Disadvantages:
- must be delivered from abroad
What can you charge with a solar backpack?
A solar backpack is ideal for trips where there is no power outlet nearby for a long time. For example, on a hiking or cycling tour, on a visit to the beach or when camping. Most devices charge with an average of five to ten watts. This means that a conventional smartphone battery takes about two to three hours to be fully charged again. Although this does not come close to the charging capacity of sockets, it is sufficient to supply smaller devices with electricity independently on the go. These include:
- smartphones and smartwatches
- cameras
- power banks
- tablets
- headphones and speakers
- navigation devices
The output of the solar cells should not be less than five watts and the conversion energy efficiency should be at least 20 percent – otherwise the hike or the day at the beach will be over before the devices are even remotely recharged.
Important: The charging speed of a solar backpack is of course dependent on the weather. When the sun is shining brightly, the panel has more convertible energy available than on a cloudy or rainy day, so a connected device charges faster.
DIY: External solar panel for backpacks
If you don’t want to buy a new backpack or want to be a little more flexible in use, you can use a universal solar panel. These are not tied to a model or manufacturer and can also be used as power banks apart from the backpacks.
Anchor power port
For example, the solar charger from Anker. It can be unfolded so that all three solar cells absorb and convert energy. The result: 21 watts of charging power for smartphones, tablets and the like. The panel can be attached to backpacks, bags or other objects using the eyelets at the ends using snap hooks. With a little creativity you can make your own solar backpack.
The only drawback: the included micro-USB cable does not meet the standard of modern cell phones and tablets that have a USB-C port. However, the normal smartphone charging cable can be easily connected to the solar panel.
| Anchor power port | |
|---|---|
| Performance | 21 watts |
| efficiency | 21.5 to 23.5 percent |
| Dimensions | 28.2 x 16 centimeters (folded), 67.1 x 28.2 centimeters (unfolded) |
| Weight | 0.42 kilograms |
| features | Foldable, with inside pocket, 2 USB ports |
Advantages:
- three panels
- high performance
Disadvantages:
- The cable that comes with it is micro USB
- no internal energy storage
Also interesting: The best power banks for smartphones in comparison
Sunnybag Leaf Pro
The Solar Panel Leaf Pro from Sunnybag is also recommended. The integrated battery is charged within two hours and charges both smartphones and tablets, among other things. The power is 7.5 watts. The panel weighs less than 400 grams and, according to the manufacturer, should be scratch, water and shock resistant. In addition, an auto-restart for iOS devices is integrated.
It can be attached to the backpack using the supplied loops, carabiners or suction cups. In addition, Sunnybag offers a refund of the purchase price if you are not satisfied. The refund can be claimed within 60 days of purchase.
| Sunnybag Leaf Pro | |
|---|---|
| Performance | 7.5 watts |
| efficiency | 22.4 percent |
| Dimensions | 28.5 x 24.5 x 0.25 centimeters |
| Weight | 349 grams |
| features | Multiple mounting options, waterproof |
Advantages:
- great job
- Battery charged very quickly
- usable for many devices
- very easy
Disadvantages:
- a bit expensive
- only one panel
Big Blue 28W
Bigblue also offers a solar panel for backpacks. The solar cells can convert up to 24 percent of the sun’s energy into electricity. A Type-C cable is built right in to charge Android devices. For other devices, such as those from Apple, you have to purchase an additional cable. Thanks to the integrated USB ports, it is possible to charge two devices at the same time.
The panel is suitable for various outdoor activities. Among other things, you can use it for camping, climbing or fishing. Thanks to the PET polymer surface, it is waterproof and robust. The four panels should also ensure that the devices are charged quickly and safely.
| Big Blue 28W | |
|---|---|
| Performance | 28 watts |
| efficiency | 24 percent |
| Dimensions | 28.2 x 16 x 3.4 centimeters (folded), 84 x 28.2 x 0.5 centimeters (opened) |
| Weight | 671 grams |
| features | many compartments, 4 panels waterproof |
Advantages:
- 4 panels
- waterproof
- Multiple devices can be charged at the same time
- suitable for Android and iOS devices
Disadvantages:
- a bit expensive
- heavier than the other models
Conclusion: Solar backpacks and panels are ideal outdoor companions
Even if the concept of solar backpacks is still quite new and the selection is therefore not too extensive, there are strong models in the selection. The bags can be used flexibly – they are suitable both for the tour by bike and for the next hike. Of course, the small cells cannot compete with the power of a socket or a solar generator. However, they are ideal for charging your cell phone or tablet on the go. Thanks to hidden compartments and plenty of storage space, the backpacks are even impressive without the solar panel – or in the rain, when the energy yield is rather meager.