Portable solar panels can charge the device anywhere the sun shines. They can also be used to charge portable power stations, which are often packaged as solar generators-clean and quiet alternatives to portable generators that do not rely on natural gas.

Before you buy portable solar panels for camping, define your needs and the situations in which you are most likely to use them. How much power do you actually need? How portable does it need to be? Will you hike with it? Throw it in the back of your car? Use it only at home? How fast do you need to charge your devices or batteries?

Whether you've already determined the answers to these questions or not, check out our picks for the best portable solar panels. I chose what I thought were the best options based on size, charging needs, and application. In addition to highlighting our favorites, I'll let you know what other models I considered and how I made my decision. That way, you can carefully consider which option is best for you.

What is a watt when it comes to the size of a solar panel?
If you've only ever encountered the measurement of watts in one place, it's probably a light bulb. With light bulbs, it measures the amount of energy it takes to light the bulb. A 60-watt bulb requires 60 watts to turn on. Since solar panels produce energy, rather than consume it, the measurement here is how much energy they produce. A 100-watt solar panel can produce 100 watts of electricity at a time when it is running at full capacity.

If you use a 100-watt solar panel to charge a 300-watt hour battery, you might think it would take 3 hours to fully charge it. 100 watts of power generation times 3 hours equals 300 watt-hours. It's actually a bit more complicated because charging the last part of the battery usually takes longer than the first part for a number of complicated reasons.

Why isn't my solar panel charging as expected?
You buy a 100-watt solar panel, plug it into a power station, and it tells you how much power is coming in. Instead of 100 watts, your power station shows 80 watts or 50 watts or whatever. Is your panel broken?

While I can't rule out that your panels are bad, there are many reasons why solar charging increases and decreases that shouldn't make you send your panels back to the manufacturer.

Since solar panels convert sunlight into electricity, the amount of sunlight hitting the panels has a direct impact on their output. Aside from the obvious factors like cloud cover or shadows, the angle of the sun or the angle of the panels to the sun can also have an effect. You can try tilting the panel so that it faces the sun more directly.

Solar panels don't work as efficiently in high temperatures. If it's hot, you may see a decrease in power generation. If you're using solar panels in a dusty area, such as a campground, washing the dust off of them will also increase their output.

How fast will a portable solar panel charge my device?
The answer to this question relies on factors on both sides of the equation: the solar panel and the device.

How much energy your solar panel produces depends directly on the sun available. A solar panel will charge a device more slowly on partly cloudy days than on clear ones. A dirty solar panel will charge devices more slowly for the same reason. Anything that gets between the panel and the sun means less power for your phone.

A larger solar panel that can collect more sunlight could charge devices more quickly: A 200-watt solar panel can generate twice the power of a 100-watt solar panel. It's not all up to the panel, though.

Charging speed can also be limited by your device. Solar generators, for example, have a maximum solar input allowable. Under the same conditions, a solar generator limited to a single 100-watt solar panel won't charge as fast as one that can connect to four 100-watt solar panels. Further, if your device supports fast charging it will outpace one that doesn't.