Why your solar-powered power bank isn't as reliable as you think (and what to use instead)

Solar-powered power banks seem like a fantastic idea; attach some solar panels to a power bank, and you have a free power source whenever the sun is shining.

However, the reality is different from this idyllic vision of limitless energy.

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I’ve tested nearly two dozen solar-powered power banks, ranging from devices purchased online to ones bought from camping and outdoor supply stores. Unfortunately, every single device has been disappointingly ineffective — and some have even been potentially dangerous.

Using such a device means placing a power bank, a box filled with lithium-ion batteries, in direct sunlight. And that’s a big problem. I’ve found that a power bank left in the sun on a modestly hot day can hit temperatures as high as 80°C/176°F, which is incredibly hot for lithium batteries. 

Not only do those temperatures push the devices to a dangerous area, but those heat levels mean the charge controller is likely to prevent the batteries from charging, which defeats the purpose of leaving the power bank out in the sun.

Another big problem is that I haven’t found a power bank that will charge to any serious level using the sun. I’ve left solar-powered power banks in the sun for days, which never charge fully. Most of them fail to hit the halfway point.

The bottom line is that I can’t recommend a single solar-powered power bank. They’re all at various tiers of garbage. I’m not saying there aren’t good chargers out ther,e but I’ve yet to find one.

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So, what do I recommend?

There are great power banks designed to use small solar panels, such as the Jackery Explorer Plus 100 and SolarSaga 40W. Alternatively, you can always use a solar power station, or go old school and charge things from your vehicle, if there’s one handy.

None of these options is as conveniently packaged as a small solar panel slapped on a power bank. However, since that arrangement doesn’t work very well, it’s better to go with something reliable and safe.