People who like to explore hard-to-reach or remote places need a power source for the gadgets they carry with them (phone, GPS, flashlight, etc.) The first things that come to mind are external batteries or mini wind turbines. There’s another option, which takes up less space in a backpack: a hand-cranked generator.
We chose, as an example, the most popular product of its kind available on Amazon, the Portable Hand Crank Generator from HUABAN. It is made of metal and is classified as “rugged”.
The device measures 106 x 64 x 39 mm, weighs 480 grams, and has a maximum output of 30 W. Depending on the speed at which the crank is turned, as well as the device being charged, the voltage can vary in the range 0 – 28 V, and the maximum current can reach 3 A (current normally varies in the range 1.5 – 2 A, according to the manufacturer).
The kit also includes a regulator. The manufacturer recommends setting it to 5 V when charging small electronics such as mobile phones or tablets to prevent their batteries from degrading over time.
For stable charging of a phone, the user should turn the crank about 2 times per second. Theoretically, if the user manages to get 5 W of power, they can charge an 1,800 mAh battery in about 2.5 hours of cranking.
But in practice, the current each device accepts from such a generator varies from model to model, depending on how the manufacturer has programmed it, so it’s hard to make an accurate calculation. One user claims that his Samsung Galaxy S9+ phone only accepted a current of 0.28 A, while an external battery received 1.0 A. He also says that a Pixel 3a received a current of only 0.04 A! Many users claim that Apple devices refuse to be charged using the hand crank generator.
Certainly the generator works and can be used to charge electronics (apparently only non-Apple), but more as an emergency or backup option that deserves a place in your luggage. More simply, cranking for a few minutes can get you a few minutes of phone use.
The device described in this article costs $139 on Amazon and has a 4.1 out of 5 star rating (highest in its category), received from 147 customers.
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