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Did you know that the first design for the solar backpack was patented way back in 2006? However, it’s only been in recent years that it became commercially available on a worldwide scale.
This is likely due to two factors. First, there is an ever growing need to stay connected, critical with the digital age, especially for the growing number of mobile workers. Second, the advancement of photovoltaic technology provides the ability to produce better solar backpacks that have a wide range of uses.
With so many options in the market, choosing the best solar backpack can be tough. That is why we put together this guide to help you buy the right one for your needs.
What is a solar backpack?
Also known as solar panel backpack, solar power backpack or, more correctly, solar powered backpack, it is literally a backpack integrated with a mini solar panel system. The photovoltaic panels are attached to the top or back of the backpack.
The purpose of integrating this solar generating power into the backpack is to allow the user to have access to a regular supply of electricity while he or she is on the go.
Whenever the PV panel is exposed to sufficient sunlight, it produces electricity to be used immediately for powering electrical devices, or to be stored in a power bank or solar battery. The largest device that can be charged using a solar backpack is a laptop.
Types of solar backpacks
Solar powered backpacks can be classified according to the uses they are intended for, as a:
- Laptop backpack
- Casual backpack
- Work backpack
- Athlete’s backpack
- Outdoor hiking backpack
Features of solar backpacks:
- Sewn-in solar panel
- Detachable solar panel
- Power bank, battery bank or solar battery
- Power banks that can be charged via AC wall outlet
- Charge controller
- Cable heads and leads
- Hydration bladder pack (built-in water storage area)
The size of a solar backpack varies too, from 15 liters to more than 40 liters. Similarly, the wattage capability of the solar panel also varies from as low as 6 Watts to the rare high of 18 Watts.
Some are made from monocrystalline and polycrystalline silicon, which are the most efficient. However, they are rigid, so they are easily breakable. Some are made from flexible thin films which are less likely to break but are not as efficient.
Detachable solar panel kits allow you to use them separately from the bag. This is convenient when you don’t need to carry them around, or when you need to place them in a stationary, sunny spot.
Some solar backpacks which are made for urban usage also come with anti-theft features. There are also those specifically for the outdoors that are waterproof.
How do solar backpacks work?
The PV cells in the solar panels on the backpack convert sunlight into electrical energy. This only works when there is exposure to a decent amount of sunlight.
The amount of electricity that can be generated is influenced by this as well as the wattage output capability of the solar panel. Most decent solar backpacks can produce 120 watts per day.
If the solar backpack doesn’t come with a charge controller or battery, the electricity has to be used immediately. You won’t have a supply of power at night or in dim places with this type of solar backpack.
Buying guide for the best solar backpack
What’s suitable for you may not be the same for another person. The ‘best’ solar backpack would fit your specific needs, which you know best. Therefore, when making your selection, take the following aspects into account.
What do you need the solar backpack for? You can’t expect one size to fit all. An outdoor hiking solar backpack may make you look macho but it will end up being cumbersome if you expect it to function like an athlete’s backpack. Cyclists and runners don’t need such a big bag.
What do you need the solar backpack to do for you? This leads us to the rest of the aspects to consider.
How much and what do you need to carry in this backpack? Plan ahead. The size of the solar backpack is measured by liters. This tells you roughly how much can be stored.
Bear in mind that the bigger the bag and solar panel system, the more weight you’ll be carrying. Some backpacks are lightweight but durability may be affected. Some better quality ones already bear some weight even without any contents.
A 15-liter solar backpack may be enough for your laptop, its accessories, a few other small gadgets and a day’s supply of necessities. The larger ones like the 40-liter backpack might suit hikers or professional photographers who have lots of gear.
The higher the watts of the solar panel, the faster the charge time. Anything less than 5W will take too long to charge your devices. Look at the wattage rating of the solar backpack before you buy it. Laptops need more power so a 10W solar panel can do the job better though it will still take at least a few hours.
Solar panels can and do break, even flexible solar cells. Once one of the PV cells in a panel is spoiled, the whole panel becomes useless. Most solar backpacks have a 1-year warranty while some have a lifetime warranty.
Pay peanuts and you’ll probably get monkeys. The price tag often correlates with the quality of the solar backpack – for both the backpack and the solar kit.
If you need something that’s reliable and durable, you might want to avoid the al-cheapo options. These won’t survive long for heavy duty use. The solar panels might also be easily damaged or be poorly made.
Do you need your devices to be charged quickly? Do you need panels that can charge your batteries quickly? If solar is your only source of power, fast charging time will be essential. The higher the wattage of the solar panels, the faster the charging time.
As a rough estimate, a higher end solar backpack can usually charge a smartphone fully in 2 to 3 hours of sunlight. Cheaper ones with lower quality panels may take double that time.
Wall outlet charging
When sunlight conditions are not great, the solar panel won’t be able to work properly. Even on a good day, it needs at least a few hours a day to fully charge the battery. Having a solar battery that can also be charged via a regular wall outlet is really handy.
Removable solar panels
Do you want to be able to use your backpack while the solar panels do their work somewhere else? Then you should opt for removable solar panels instead of the permanently sewn-in ones. Solar backpacks with removable solar panels have ready-made points for attaching the panel kit, holes and nooks for outlet cables.
Are you likely to be in situations where you’ll get wet? Not all backpacks are waterproof. Not all solar panels are waterproof either.
This may not be a great issue if you’re fine with slipping on a backpack cover. But then, this will affect solar power generation since the cover will block some or all of the sunlight.
This leads to the next question: do you need your panels to work all the time despite rain or shine? If the answer is yes, then go for a solar backpack that is weatherproofed and waterproofed.
How long do solar backpacks last?
Several factors affect how long it can last. The first is, of course, how you use it. If you treat it with care and don’t overload it, the backpack is less likely to tear. If you treat it roughly, of course, it will wear out faster and the solar panels will be damaged sooner than they should be.
The second is quality. High quality solar backpacks will have a longer lifespan than cheap, low quality ones. On their own, solar panels can last 25 to 30 years.
You’ll need to check the fine print of warranties offered by solar backpack companies. Warranties for the backpack itself averages at 1 year.
How to make a solar powered backpack?
It is possible to turn a regular backpack into a solar charger. Solar panel kits are now sold separately just for this purpose. You’ll need to customise your backpack to fit the kit including all the necessary cables.
There have been suggestions to use heavy-duty double-sided adhesive tape but if you want the panels to be detachable as and when you wish, you’ll need to think of a better idea. Besides, there is a risk of the panels dropping off your backpack if the tape becomes wet or damp.
Do I need to purchase a battery bank or charging cords?
Yes, if the solar kit doesn’t already have these. Not all ready-made solar backpacks have them though. Depending on what you plan to charge, you may need an external battery bank with the matching cords and cable heads for your devices.
Before buying a solar backpack, take into account all your needs first. From there, you can work out the features that best serve them. There is no point in spending less or more on something that doesn’t serve its purposefully.
The second most important aspect to keep in mind is the solar panel output. The higher the wattage rating, the faster and more electricity it can produce. The bigger your electrical consumption, the more watts you should be looking at.