How PowerTrekk Works

With fuel cells, the beach itself can fuel your phone.
Image courtesy PowerTrekk

The great outdoors are awesome. There's no denying it. But many a modern hiker just needs a quick Twitter or Angry Birds break from time to time. Unfortunately, those pesky smartphone batteries inevitably run dry, and most portable chargers take up precious Clif Bar space in the old backpack.

Tech companies are well aware of this conundrum -- along with the spending practices of gadget-savvy outdoor adventurers -- so everyone from Apple to your local neighborhood startup has tried to develop portable, dependable battery-recharging technology. The latest innovation comes to us via the Swedish manufacturer myFC and the U.S.-based SiGNa Chemistry. It's called the PowerTrekk, and it's marketed as the world's first portable fuel-cell charger that runs on ordinary water.


That's right: water.

Normally the warranty-voiding bane of all smartphones, water actually enables the PowerTrekk to charge your dying device via the wonders of hydrogen fuel-cell technology. The water reacts with sodium silicide inside the PowerTrekk's puck-shaped fuel source to release hydrogen gas, which feeds into the gadget's fuel cell to produce electricity.

The water doesn't even have to be clean! You can use salt water, rain water, skunky beer, urine or even the tears of a heartbroken teen. And since the PowerTrekk is roughly the size of two smartphones stacked atop each other, there's still plenty of room inside your backpack for sustenance or any other supplies you might require.

To fully grasp how the device operates, we first have to run through the details of hydrogen fuel-cell technology.


Water Your Smartphone

Slap in a PowerTrekk puck and all you need is a little water.
Image courtesy PowerTrekk

What's a hydrogen fuel cell? It's a battery that depends on oxygen and pure hydrogen gas to convert chemical energy into electrical energy. It's portable and energy efficient, and produces only water and heat as waste products -- all qualities that make it one of the future's brightest alternative energy options.

Sounds great, right? But why isn't there a hydrogen fuel cell inside every home, car and laptop on the planet? The answer lies in the technology's key shortfall: It depends on pure hydrogen gas, and there's virtually none of that on planet Earth. All the hydrogen at our fingertips is already oxidized or tied up in fossil fuel hydrocarbons, so the challenge becomes unlocking that hydrogen gas without depending on oil or spending excessive energy in the process.


The buzz around hydrogen fuel-cell technology often relates to automobiles -- and, indeed, the notion of a pocket-sized fuel cell used to seem a bit silly. Hydrogen gas has been notoriously difficult to store, requiring a pressurized steel tank. But myFC and SiGNa Chemistry took a different approach, choosing to harvest the gas via chemical reaction. So instead of having to store volatile hydrogen gas in sealed tools, a PowerTrekk user can just collect it from where nature stores it: good old H20.

The top half of the PowerTrekk contains the system's fuel cell, interface and USB hookups. It also features a separate battery that can work independently of the fuel cell or in unison as an energy storage buffer. The bottom half features two compartments: one for water and one for an inserted fuel puck containing sodium silicide, produced from sand and table salt [source: Sorensen].

When the sodium silicide (NaSi) comes in contact with water (H2O), the resulting chemical reaction releases aqueous sodium silicate (Na2Si2O5), hydrogen gas (H2) and energy (kilojoules per mole). It all breaks down like this [source: Sorensen]:

2NaSi + 5H2O -> Na2Si2O5 + 5H2 + 350 kJ/mol

But I know what you're wondering: How much does it cost? Can I bring it on an airplane? If I drop it in the sea will it convert the world's oceans to hydrogen gas?

Let's find out.


The Fuel Cell in the Woods

Don't be afraid to use the last of your drinking water.
Image courtesy PowerTrekk

Load a single PowerTrekk fuel puck, pour a little bit of water into the corresponding reservoir and you've got yourself 5 watts of power -- enough juice to fully recharge the average smartphone in the space of an hour and a half. It also works on other USB and mini-USB gadgets such as GPS devices and digital cameras.

Sure, the PowerTrekk isn't the only gadget on the market capable of filling your power meter back up. It's not the smallest or the cheapest. But fuel-cell technology brings with it a few key advantages. For starters, it's fairly light at 8.6 ounces (244 grams), so a little emergency power for your gadgets won't weigh you down. Another advantage it holds over competing charging systems is that it doesn't discharge power or degrade over time.


The PowerTrekk is slated for commercial release in fall of 2012, with an estimated price tag of $229.99. The single-use fuel pucks will run three for $11.99 [source: Industrial Revolution]. In the meantime, the product already has International Electrotechnical Commission (IEC) approval, so you'll have no problem bringing it on an airplane.

What does the future hold for this technology? MyFC and SiGNa hope to incorporate the technology into additional gadgets (SiGnA actually employed its sodium silicide fuel cell back in 2010 in an electric bicycle design). In time, they hope to help revitalize the fuel-cell industry itself, which lost serious steam in the early 2000s.

If successful, you can count on seeing similar fuel-cell systems integrated into a whole host of future mobile devices. In fact, Apple filed two patents back in 2010 related to very similar gadget-charging fuel-cell systems [source: Woyke].

In time, we may actually reach the point where a fuel puck and a little aqua in the tank is all it takes to embark on a cross-country road trip. Until then, at least we'll be able to recharge the phone.


Author's Note

Senior Staff Writer Robert Lamb
HowStuffWorks 2009

There's a lot of fun to be had ridiculing nature-loving hikers for their high-tech gadget addictions, but ultimately devices like the PowerTrekk are an absolute good. In the short term, they enable an easy way to recharge life-saving navigation and communication technology in the wild. In the long term, they might just push the technology along to the point where hydrogen fuel cells provide the world with a truly clean alternative power source.

Plus, how awesome is it that any watery liquid will do. Beer, urine, drinking water, scummy water -- it's all good inside the PowerTrekk. I'm not so sure about blood, however. I suppose that's going too far, even for one more round of Words With Friends.


Related Articles


  • (July 9, 2012)
  • "Powertrekk." Industrial Revolution. (July 9, 2012)
  • Sorell, Charlie. "PowerTrekk Fuel Cell Charger for Hikers, Bikers." Wired. Jan 16, 2012. (July 9, 2012)
  • Sorensen, Bent. "Hydrogen and Fuel Cells: Emerging Technologies and Applications." Academic Press. Nov. 15, 2011. (July 9, 2012)
  • Woyke, Elizabeth. "CES Preview: Fuel Cells Coming To Gadgets, Finally." Forbes. Dec. 30, 2011. (July 9, 2012)