External battery packs come in all shapes and sizes, but there's something about a solar panel that makes me want one more. I conjure up images of a battery that never dies and never needs to be charged, that can get me through a power outage after a summer hurricane with an overabundance of energy.In reality, ZeroLemon's Solar Juice power banks might reach a full charge after several days of optimal sunlight. Fortunately, they're good external batteries in other ways. They're water, dust, and shock resistant. They come with two USB ports. They also offer a flashlight. Then there is the generous capacity.ZeroLemon makes many sizes, but today you can get the company's 20,000mAh battery for $19.98 on Amazon. You just have to enter the coupon code Z36GZOGN at checkout to drop the price down from $47.88.

This discount is more than half off and a great price to pay for such a solid battery. It's also $10 less than the price we saw last month. The seller is only offering 800 units at this price, so grab one while you can. You won't get fast charging, but you do get to power your phone several times and have a back up plan if you find yourself stranded from an outlet when your external battery dies.

Source: Amazon