How big is the battery of outdoor mobile power bank

There's a 12,000mAh capacity power bank and a separate folding solar panel of clamshell design that delivers a max output of 5W. The power bank has a 2.0A USB output as well as a USB-C port and, uniquely among the power banks in this test, a 12V DC outlet.

Fortunately, there's an easy equation to figure out the size you need. Let's say that your power bank has 5,000 mAh. You need to multiply the capacity by the volt rating to get the mWh: the megawatt-hour rating. Then, divide that by the voltage rating of your phone– 5V.

Power banks are available in a wide range of capacities, from as little as 1000 mAh to as much as 50,000 mAh or more. However, it's worth noting that as the mAh capacity of a power bank increases, so does its physical size and weight– which can be a serious detriment in the backcountry or while traveling. Bigger is not always better!

At less than 4 inches long and shorter than 3 inches high, and weighing a mere 7 ounces, this power bank is a great fit for an ultralight backpacker or somebody who doesn't want to be weighed down with a bigger bank. This beefy bank can charge up to six devices at once, making it almost feel like a lighter power station.

Generally, capacity is measured in milliamps per hour, or mAh. This unit indicates how many milliamps of electric current a given power bank can deliver per hour. Power bank capacities can get down below 3,0000 mAh, but generally, that's as low as you should consider going.

For this range of power banks, you can pay anywhere from $20 to $160. Power banks with a capacity rating of 20,000 mAh or larger are the most versatile of the group. They offer the greatest array of inputs and outputs as they are designed to charge multiple devices at once or charge a single device multiple times.