DIY Salt Water, Earth and Sand Batteries in Taiwan

I’ve been researching Salt Water Batteries for the past week or so. Im rained in now, so might as well learn how to build a prototype today.

I have a one month plan to:

  • Light an LED
  • Run a small motor
  • Charge a mobile.
  • Charge a laptop.
  • Run a medium sized fan.
  • Run a 10 watt Marshall amplifier.

Using a salt water battery setup.

I made a scrappy research document here:

I will make the first electrodes out of aluminium and copper, but hope to graduate to graphite and magnesium.

If anyone has any ideas, please let me know.

NOTE: 1) I understand that Salt Water batteries are not as efficient as lithium, and may end up ten times the size of a regular battery. However, there are many, many benefits. They’re being produced by many companies now.

Tons of good videos on youtube, from DIY set ups, to commercial rigs.


Good luck. I like to watch this channel for new ideas.

Cheers. At first I felt embarrassed, having to look up junior school physics and chemistry experiments that I’ve forgotten about.

Then I decided to take it slow, and enjoy the journey.

I came across his channel in a search. There’s some amazing stuff on youtube if you make the effort.

Baghdad batteries are pretty cool…

My question is how are you going to charge it, solar panel?

I will look at homemade solar later.

Regarding charging; From what I’ve seen, salt water batteries seem to get a small voltage from the materials themselves.

You can get 0.5 volts from most materials. Graphite plus magnesium (the best combination) gets you nearly 2 volts. Easily enough to run a light or (closer to 5 volts) charge a mobile phone. There are many videos on youtube.

Charging a phone is just a cool gimmick. I’d like to make something bigger.

Once you link a few cells together in series, you can get higher voltages, and charge a laptop, or a small fan. Yes, the batteries are 10x bigger, but they are environmentally friendly, and liberating on many practical levels.

People are powering their farms from huge, commercial units. There are many vids in the doc I linked.

Your Shovel Guitar is the talk of the town, BTW. People are almost queuing up to see it. I have many stories. Looking forward to making an upgrade next time I have some spare cash.

If you talk me through the practicalities of making a salt water battery display, the HHC roadshow will get even better. I hope to power lights and a fan within a month.

Check these videos.

Do you know where I could buy magnesium or graphite rods/electrodes?

I know I can get graphite from pencils.

This guy has a fairly solid design. He’s using dirt, not salt. And just nails and copper as Cathode/Anode pairs. You couldn’t charge more than an LCD device with a battery his size… but what he built can be scaled. Multiple racks of ice-trays hooked in series could be good.

There are people getting well over 100 volts in some videos.

Having thought about it, his design is one of the best out there. It also dispenses with the issues of sloshing water, and other salt water issues.

Imagine powering a small marshall amp from something like this.

I guess check hardware stores and see if they have graphite rods for welding… No pencil is useless.

As for magnesium I don’t know. Do you mean magnaese dioxide?

Lots of good info from the comments:

Electricity is induced when two dissimilar alloys are in the presence of an electrolyte. You would improve upon this model by having a copper rod, your zinc coated bolts (galvanized) in each of the cells (cubes) then connecting them in series until the desired voltage is reached (may have to increase the number of cells under a load) then connect the same about in parallel to increase the amp hour rating of each earth battery so that is can power useful things (chargers ect.) You might also introduce a bit of salt water (an electrolyte) to improve conductivity and the electrolysis process.

So metal blends touching something that has electrolytes (or heat)?

You may consider looking up “the Seebeck effect”. Fascinating stuff

What is the Seebeck effect?.

Graphite rods for welding, good idea.

Interestingly, Aquion (a commercial salt battery firm) use manganese in their design IIRC. It’s in the first videos I linked.

But the Indian Genius kid is using Magnesium, not Manganese. I’d happily use either, if I knew where to source them in Taipei.

Im open to any easy to obtain materials.

Anode/Cathode composition is key. You can get much higher voltages if you choose the right combination.

Employee of the month, an inanimate carbon rod…

Yes you create electricity when you stick electrodes into some solution. The solution can be lemon, potatoes, or whatever.

The key though is the reaction wont last forever. You gotta put electricity into it to charge it. Otherwise it gets extremely expensive replacing chemicals.

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I have some magnesium. Have to buy it from taobao. It’s really expensive.

Ha, yes. Graphite seems to be best. Is that on Taobao or something? I’d prefer to source everything from a local suidian, or Guanghua, in Zhongxiao Xinsheng.

You’re right that the reaction eventually ends, and that is a minor hassle. People have come up with various hacks.

  • Im patient enough to change the dirt every couple of days, if I managed to run a small amp. That would be damn useful, cos it’d mean I could play on a proper amp outside.

From the ice-cube tray video, he says this in the description:

TO RECHARGE THE BATTERY; just add 1 or 2 teaspoons of water to each “cell” and the battery will be “recharged”. for increased voltage make more than one battery and hook them together.

I might just stick with nails and copper then. I’ve spent a week watching various vids. He seems to have the best design.

The more I think about it, Earth batteries might be better than salt water.

Reason I post taobao link is because a lot of these specialized stuff are harder to source. Sometimes you get a blank stare when you ask for it.

and I know magnesium is expensive as hell.

I get blank stares 3 times a week. Foreigners are used to it.

This guy is powering a radio from soil/ice cube trays and wire/nail pairs. Seems like a solid design.

Oh wait, the radio consumes the power pretty quickly. maybe salt is better.

Either way, with salt or dirt, ice cube trays make good cells.