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Environment

LED lantern runs on saltwater

By David Szondy
September 07, 2012
LED lantern runs on saltwater
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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Japanese directions for using the lantern
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Japanese directions for using the lantern
Details of the GH-LED10WBW
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Details of the GH-LED10WBW
The GH-LED10WBW is intended for use in emergencies, and for recreation
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The GH-LED10WBW is intended for use in emergencies, and for recreation
Japanese directions for using the lantern
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Japanese directions for using the lantern
Details of the GH-LED10WBW
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Details of the GH-LED10WBW
The GH-LED10WBW is intended for use in emergencies, and for recreation
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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

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EnvironmentLEDBatteryLightElectrolyteMagnesium
8 comments
David Szondy
David Szondy
David Szondy is a playwright, author and journalist based in Seattle, Washington. A retired field archaeologist and university lecturer, he has a background in the history of science, technology, and medicine with a particular emphasis on aerospace, military, and cybernetic subjects. In addition, he is the author of four award-winning plays, a novel, reviews, and a plethora of scholarly works ranging from industrial archaeology to law. David has worked as a feature writer for many international magazines and has been a feature writer for New Atlas since 2011.

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8 comments
Tony Smale
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).
piperTom
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.
Dan Marsh
Seems totally pointless given that the rods only last 120 hours. Another one for the landfill!
Terry Penrose
Good points there Tony S, at this stage it's little better than a curiosity
Bruce H. Anderson
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.
J.D. Ray
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.
oldbilbo
I was recently required to use 'emergency lanterns' on a small offshore sailboat, as my safety-essential 12v navigation lights ( port, starboard, stern ) failed through corrosion. These are truly needed for one to be seen by shipping, so they can avoid you! I fitted small battery-powered lights with conventional incandescent bulbs and AA cells, but they were weak and didn't last long. I also hung a 24-LED camping lantern on the backstay, which helped as a stern light, but this wouldn't survive long in a corrosive salt-spray environment.
This is one guy who encourages the development of these salt-water 'luminaires'....
unklmurray
Solar panels are NOT as readily available as salt water,magnesium rods are easier to store and are 'Greener' than your AA,and AAA batteries, solar panels are bulky ,the 12v batteries are heavy and are much harder to get and maintain than salt water.