The power goes out and you need a flashlight, but then you realize you don’t have any batteries, or maybe they’re dead.
The Hydralight may be a solution. It’s a flashlight that’s supposed to run on water.
But will it work?
It's powered by a water-activated fuel cell and it seems simple: twist off the bottom and remove the fuel cell. Then immerse it in water for about ten seconds to generate power, shake out the water, then put the fuel cell back into the Hydralight.
It worked on our first try, but it's very dim compared to several flashlights we tried.
On to the next test! The Hydralight is more than just a flashlight. By extending the barrel, it becomes a hands-free lantern. And that works too!
Now for the real test!
The claim is it can run for days on one water dip, as long as you don't turn it off. If you turn it off and the water dries out, the light doesn't turn on. You simply have to re-dip the fuel cell.
Each cell is supposed to get up to 300 hours, so we left the flashlight on until it turned off on its own...
After about 36 hours, it's much dimmer, but it's still on.
After about 50 hours, the flashlight was more like a night light.
And at 60 hours, there was no shine at all.
Still, it turned right back on when we dipped the fuel cell in water again.
The Hydralight sells for $29.95 plus free shipping and a two-pack of fuel cells will cost you about 30 bucks.
So how does it rank on our bull/no bull meter? I'm a little torn.
It did run on water, but I wasn't impressed with the brightness at all.
It also did not last 100 hours on one water dip.
So you decide if it's worth the cash!
If you’re really looking for an emergency light, hand-cranked flashlights might be the better option.