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In a power outage, having a back-up source of light is important, and while there are lots of battery-powered as well as solar-charging options, sometimes the power will be out in a situation where batteries and sunlight are scarce. Having a light source that doesn’t need anything to charge besides water and salt can be a good alternative in a pinch.
Why you need a salt-water light in your emergency kit
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In some cases, batteries and solar-powered cells will only get you so far. Keeping batteries in a vehicle, for instance, can cause them to corrode, leading to flashlight failure in a critical moment. If it’s dark outside and your power is out, a solar-charging light won’t work. Sometimes, candles are dangerous to use, or circumstances are too wet outdoors to use a candle reliably. In these circumstances, having a salt-water-powered light source can be a big help. You can keep table salt indefinitely as long as it stays dry, so it’s a practical emergency resource to have on hand. Having a few different options for light sources will make your emergency kit more adaptable for a variety of circumstances.
How a salt-water light works
Using salt water to generate electricity works by causing a chemical reaction using oxygen and magnesium. The salt water is conductive, and completes the circuit between the magnesium, which acts as the positive electrode, and oxygen, which acts as the negative electrode, thus producing electricity through the process of ionization. In an emergency, you can also use urine to power a salt-water light if you don’t have access to salt or water.
Where to get a salt-water light
While reusable salt water lamps like the Waterlight or the Maxell SaltWater LED Lantern aren’t widely available in the U.S., there are some limited-use alternatives that will come in handy in a pinch. The WATTerLight will produce 50 lumens of light for up to 140 hours with just salt and water. You can use the WATTerlight more than once if it is stored correctly. The HydraLight flashlight is a compact version that only needs water to activate, will provide 72 hours of light, and will fit in your pocket. If you really want a reusable salt-water-powered lamp, you can comb sites like eBay or European and Asian suppliers for sources.
How to store a salt-water light
Make sure to store your light in a dry place, and if you have a reusable version, dry it out thoroughly before storing it between uses. This will prevent the magnesium from releasing a charge in between uses. To clean the outside of the light, you should use a damp but not wet cloth, and make sure the outside is dry before packing it away. If it’s possible that the lamp will get damp, use a Ziploc bag to keep moisture from getting to it.