Let's Make Robots!

Viable Potato Batteries?

I'm sure many of us experimented as kids with turning a potato into a battery. I recently re-lived this experience with my seven year old son. It is a fun experiment, but the batteries produce limited voltage and current, so they are not terribly practical.

Now, researchers as Yissum Research and Development have come up with a way to increase the energy you can get from a potato battery by up to 10 times! They simply boiled it first. You can read the engadget story, or Yissum's orginal paper.

I'm thinking of issuing a challenge for building a robot powered exclusively by potato battery (other vegetables also acceptable). Any interest?

I'm out of town right now, but I'm going to try this out when I get home.

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The first telegraph systems used "Earth Batteries" ...... exactly..... diss-simular metal electrodes stuck into the ground at a suitable distance........

Believe or not i tried this 2weeks ago ...... and at 1 meter distance i generated a staggering 0.4Volts (knock me down with a feather)

So i suppose anything goes...

I've made a battery from a lemon and also from beer. Sound like much the same results.

I think boiling the potato makes it a bit pointless as you are putting about 10,000 time the energy in as heat compared to what you get out.

Still... what happens if you boil the lemon, will you get more out of it?

As for the beer, Drink it!

Lemons are nice and acidic, and they actually work better than potatos (at least, unboiled ones). I'm not sure what effect boiling a lemon will have. Maybe making lemon tea.

I've never tried using beer as the electrolyte for a battery. I guess I've always had a better use for the stuff. ; j

It is true if you are looking at overall energy expended that boiling uses a lot of energy. This is more about learning some basic science in a fun way than about building a practical robot.


This will be the first metalo-vegetarian robot on LMR (and probably the world).

Anybody know where I can get some zinc and copper foil?

How to get zinc from a lantern battery.

I think you can buy copper sheet from a hardware store. Copper flashing for roofs and such.

I know about zinc carbon cells, I used to do that as a kid, but I need more, and preferably thinner

Bad ass. A Mr. Potatohead robot dream can now be realized. Going to see how this works too when I get a chance. 10x more power. What exactly does that mean... I must find out.

I'm assuming more current for the same voltages, but I'm not sure. Experiments will be conducted.

.. but what I mean is are we talking from 1uA to 10uA or 1mA to 10mA? I know a potato cell built back in my childhood didn't make enough current to light a lamp so I was just wondering out loud. Yes, can't wait to play with my spud!

"I just boiled up a 2400mAH 3S 100P tuber pack. One question... how do I recharge it?" :)

Without boiling, it would take 2-3 potatoes to light a LED, as I recall. I think that was to get the voltage high enough, and the LED wouldn't typically glow very brightly (or require a current limiting resistor).

So maybe each potato is 0.5 to 0.8 volts and all together you probably got less than 10mA.

I believe you get better results if your anode and cathode have a lot of surface area. So a strip of metal would work better than a wire, for example. I've been thinking about using a series of alternating zinc and copper plates to get higher voltage out of one potato. I imagine multiple plates in one potato will not last as long overall, but I need to try it.