Build Your Own Hand-Cranked Powerbank to Charge Your Phone in Emergencies




Like most people, you probably rely very heavily on your smart phone. And we’ve all experienced the inconvenience of a dead phone battery, which is a hassle even when you’re just out running errands. However, that inconvenience can easily turn into a legitimately dangerous situation if your phone dies during an emergency. In this Instructables tutorial, GreatScottLab will walk you through how to build an emergency hand-cranked powerbank generator to charge your phone in a situation like that.

In the YouTube video below, GreatScott! spends a lot of time thoroughly explaining how this hand-cranked generator works, and why his initial designs failed. Originally he was planning on using a BLDC (brushless direct current) motor like you’d use for a drone. But those are designed to run at a high RPM, which means they have to be turned at a high RPM to produce a sufficient amount of power to charge a powerbank. He was able to improve the low RPM performance a bit by rewinding the motor, but ultimately it just wasn’t enough.

Switching to a geared DC motor dramatically improved the performance. Geared motors take the high RPM output of a DC motor and gear it down, reducing the speed and increasing the torque. The opposite is also true: turning the output shaft at a hand-crank speed spins the motor itself quickly and generates enough power to charge the powerbank’s battery. With that in mind, it’s a simple matter of connecting the motor leads to the battery. A 3D-printed case holds everything together, and a printed hand crank is used to turn the shaft. It would take several hours to fully charge your phone with this, but a few minutes should be enough to place a call in an emergency.


Build Your Own Hand-Cranked Powerbank to Charge Your Phone in Emergencies was originally published in Hackster Blog on Medium, where people are continuing the conversation by highlighting and responding to this story.

Original article: Build Your Own Hand-Cranked Powerbank to Charge Your Phone in Emergencies
Author: Cameron Coward