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LED lantern runs on saltwater


September 7, 2012

The GH-LED10WBW is intended for use in emergencies, and for recreation

The GH-LED10WBW is intended for use in emergencies, and for recreation

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Every now and again, a rumor crops up that someone has invented a motor car that runs on water. Sadly, that still remains a rumor, but Green House Co Ltd of Japan will soon be marketing an LED lantern that runs on saltwater.

Given the catchy name of GH-LED10WBW, it’s presented as a saltwater lantern, but a magnesium/carbon lantern is more accurate and the design is simple compared to other saltwater batteries. The 680-gram (23.98-oz) lantern uses 16 grams (0.56 oz) of salt dissolved with 350 cc (11.83 oz) of water in a proprietary measuring bag and then poured into the lantern. The salt acts like an electrolyte in a simple wet battery, that uses a magnesium rod as an anode and a carbon rod as a cathode. The magnesium rod is replaceable because it is slowly destroyed by electrolysis as the magnesium ions travel to the carbon rod, generating electricity.

The 1.5 volts of DC power produced by the lantern is enough to run its ten-LED white light, which puts out 55 lumens of light. The lantern also includes a USB port to charge devices at 4.5 volts. The GH-LED10WBW runs for eight hours before the saltwater needs replacing, and the magnesium rod lasts 120 hours.

Marketed as an emergency lantern or for use aboard boats, it’s scheduled to go on sale in mid-September. No price has been announced.

Source: Green House Co Ltd

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

I'll echo Tony's remarks. The problem here is the misleading headline: "...runs on saltwater." The article body clearly shows the gizmo runs on refined magnesium. No sale.


Seems totally pointless given that the rods only last 120 hours. Another one for the landfill!

Dan Marsh

I'll just whip down to the local for a packet of AA Magnesium rods...

A quick use of a famous search engine provided several LED torches around 55 lumens, all rated at around 155hours from 3xAAA batteries.

Compared to $8 (Educated Guess) worth of magnesium electrode, I cannot see very many uses for this particular device when Rechargeable NiMH batteries cost the same as 120 hours worth of Magnesium, and last 20% longer...and can be reused many many times.

I can see the storage of magnesium rod as being easier than keeping charged NiMH batteries around (But you can purchase 40 non rechargeable alkaline's for $8), but having to fill the lantern with salt water every 8 hours doesn't sound like a good return on investment to me.

A quick look at a notable booksellers website shows several Solar powered lanterns for less than $30, including rechargeable batteries.

I honestly cannot think of a use where this device is a more practical choice than existing products...except maybe in an extraterrestrial ocean-side magnesium mine. (Mg is not found in free metallic form on this planet, so energy has to be used to purify it in the first place, and that energy would be more efficient at lighting).

Tony Smale

Good points there Tony S, at this stage it's little better than a curiosity

Terry Penrose

My first impression is that it might run on seawater, which could work with those sailig the briny sea. Just dip that puppy overboard and you have a fresh charge! But it is salt water, which is different. Not only might you need to store magnesium rods, but also packets of salt. The hope is that mixing the salt and water when it is dark is a simple/spillproof process. And does the water need to be something other than plain tap/bottled water? One more vote for Mr. Smale.

Bruce H. Anderson

I agree with Bruce; if it ran on seawater, and the shelf life of the dry unit was measured in decades, then it would be a good emergency lantern for sea-going boats. Otherwise, it's one more gadget no one needs.

J.D. Ray
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