Can a Hamster Actually Charge Your Phone?

Here we go again. Energy prices are on the rise, and with them, the cost of everything else is going up as well. We can feel pretty helpless at times like these. After all, what can we do to alleviate the pain at the pump or the sting of our monthly utility bills? While we can’t control global energy markets, we aren't entirely powerless — at least not if we have hamsters.

What does a hamster have to do with any of this, you ask? In truth, not much. However, as YouTuber Flamethrower proved, we can turn their natural love for running around a spinning wheel into a phone charger. It’s not going to make a big dent in your bills, but why not reclaim that otherwise wasted energy?

The concept hinges on a straightforward bit of physics: electromagnetic induction. By spinning the shaft of a DC motor, the device effectively becomes a generator, converting mechanical motion into electrical energy. But translating a hamster’s modest sprint into something useful for modern electronics is far from simple. A typical small motor would require extremely high speeds — well beyond what a hamster can produce — to generate sufficient voltage for charging a smartphone.

To work around this, Flamethrower employed a higher-voltage, 20-volt DC motor salvaged from an old electric broom. This substitution allows usable voltage to be generated at much lower rotational speeds. Still, that only solves part of the problem. Hamsters don’t run at a constant pace, meaning the electrical output fluctuates wildly, which delicate electronics like smartphones cannot tolerate.

To solve this problem, Flamethrower decided to store energy as it is produced for later use. This was made possible using an ultra-low-power energy harvester module based on Texas Instruments’ BQ25570 chip. This component can start harvesting energy at just 330 millivolts and continue operating at even lower voltages. It also features Maximum Power Point Tracking (MPPT), dynamically adjusting to extract as much energy as possible from the hamster’s inconsistent pace.

The system stores this energy in a salvaged 18650 lithium-ion battery cell. This battery acts as a buffer, collecting small amounts of energy over time. A separate USB boost converter then steps the battery’s voltage up to a steady 5 volts, suitable for charging a phone.

A custom 3D-printed adapter connects the hamster wheel directly to the motor shaft, ensuring efficient energy transfer. Meanwhile, the battery connections are carefully constructed using spot-welded nickel strips — a safer alternative to soldering directly onto lithium-ion cells.

After assembling the system and letting the hamster run overnight, the device had enough stored energy to charge a phone. While the charging speed initially lagged, the issue turned out to be something simple — a worn-out USB cable causing excessive resistance. Swapping it for a better cable significantly improved performance.

Hamsters are certainly not the solution to our energy woes. But while your pet won’t replace the power grid anytime soon, it might just keep your phone alive in a pinch.