In round numbers, 150 potatoes will light a normal red or green LED bright enough to see. Not blink or flash, no multi-color, just glow dimly.

ak

@Aris Santas: Please ignore the criticism. You've shown that you're willing to scale this project down.

I think AK's suggestion is a good idea. I wanted to mention that using a joule thief circuit might make the LED brighter and/or allow you to use fewer potatoes. Just my two cents.

 

Surely, a 120VAC potato would be classed as a transformerless power-supply and cannot be discussed here.

 

Here's an interesting article with some lofty claims about potato potential:
http://www.bbc.com/future/story/20131112-potato-power-to-light-the-world

Let me say up front that I've forgotten what I once knew of chemistry in general, and know even less about battery chemistry in particular, but...

Could the limited power available from a potato battery be further increased by mashing the potatoes and adding enough water to make a soupy liquid? You could also use much larger electrodes. Imagine something like a car battery, but with a potato slurry instead of the usual acids. I realize that the energy comes from changes to the metal more so than from the potatoes themselves and that the electrodes would have to be replaced as they were depleted. I'm not suggesting this as a viable replacement for anything. I'm just wondering if the limiting factor in a regular potato battery is:
1) Chemical makeup of potato
2) Size of electrodes
3) Mobility of ions
4) Other stuff not listed above

Depending on the answer, there might be a way to make a more powerful (although less recognizable) potato battery.

 

Let me just say that this thread is making me howl.

The OP has to be a wind-up.

 

The OP has to be a wind-up.

You justify my Anglophilia.

 

http://www.slideshare.net/mobile/engpjk/three-kilowatt-earth-battery