8 ms·
A potato battery can light up a room for over a month (2013)
- maxerickson 6y agohttps://www.youtube.com/watch?v=36hzlFVgVa8 https://www.youtube.com/watch?v=36hzlFVgVa8 seems to be the video (didn't play for me at the link). It's really a zinc and copper plate battery. Apparently boiling the potatoes can improve the power output.
- foobar33333 6y agoYou'd have to factor in the resource usage of producing zinc and copper plates before even considering using this as a real solution.
- deleted 6y ago[deleted]
- seltzered_ 6y ago2010. (posted article from 2013). https://www.researchgate.net/profile/Boris-Rubinsky/publication/239391768_ZnCu-vegetative_batteries_bioelectrical_characterizations_and_primary_cost_analyses/links/0a85e53041fb515776000000/Zn-Cu-vegetative-batteries-bioelectrical-characterizations-and-primary-cost-analyses.pdf https://www.researchgate.net/profile/Boris-Rubinsky/publicat...
- dnhz 6y ago> To be clear, the potato is not, in and of itself, an energy source. What the potato does is simply help conduct electricity by acting as what’s called a salt-bridge between the the two metals, allowing the electron current to move freely across the wire to create electricity. Numerous fruits rich in electrolytes like bananas and strawberries can also form this chemical reaction. They're basically nature’s version of battery acid. That doesn't sound so exciting to me.
- young_unixer 6y agoIsn't that a bit like saying "The sun is not a light source, it's just very hot, which causes hydrogen to go into nuclear fusion, which releases energy in form of electromagnetic radiation"? Or is my comparison flawed?
- cma 6y agoNo, the potato is basically acting as a salt bath here. It would be more like thinking the empty space the sun's light travels through is the light source, not the sun.
- edrxty 6y agoThe energy is coming from metals rather than the potato. The potato simply links them allowing their ions to react and create an electric potential.
- soarfourmore 6y agoIwish the article described the cost, size, and rarity of the two metals, but instead it focused only on the potato
- edrxty 6y agoIf you want a deeper dive, the chemistry here is actually really simple and (IMO) very cool. I'm drawing on some really dusty knowledge here but TL;DR the cells can be modeled as two reactions, oxidation and reduction. One is gaining an ion and the other is shedding one. This is typically shown in the equation as some number of "e-". Because there are two reactions, each one is described as a half cell and there are tables[1] of all the voltages that these half cells create. Therefore you can mix and match to create batteries of arbitrary voltages, though whether they're practical is another issue. If you look at the table, you'll notice that some common battery chemistries stand out, like: Li+ + e− ⇌ Li(s) −3.0401 for lithium Ion batteries (the other reaction adding the last ~.7v to reach the nominal 3.7 cell voltage you're used to). Similarly you can find the half cells that make up a 1.5v alkaline battery[2]. [1] https://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page) https://en.wikipedia.org/wiki/Standard_electrode_potential_(... [2] https://en.wikipedia.org/wiki/Alkaline_battery https://en.wikipedia.org/wiki/Alkaline_battery
- deleted 6y ago[deleted]
- bmurray7jhu 6y agoWould the potato be safe to eat afterwards? If widely deployed, I would imagine that a non-negligible number of potatoes would be eaten after being exhausted as a battery.
- BenjiWiebe 6y agoThe potato doesn't provide the energy; the two metals do.
- mikewarot 6y agoMany copper compounds are toxic, I wouldn't even think about it.
- 0_____0 6y agozinc ain't no cakewalk either
- wolfretcrap 6y agoThen why is it used to carry drinking water
- mikewarot 6y agoDrinking water isn't a corrosive / reactive media the same way a battery is.
- ekianjo 6y agoYou dont want metal salts in your potatoes
- waspight 6y agoYou dont want to want to eat a cooked potato that is 40 days old either.
- benbenolson 6y agoDoesn't this require the degradation of the zinc and copper plates that are required for it to work?
- ddingus 6y agoYes, but the plates could be cleaned and used multiple times. For plates of reasonable size, simple abrasion would be enough.
- analog31 6y agoYes, conversion of the metallic copper and zinc into ionic salts is where the energy comes from.
- amluto 6y agoRead the paper: https://www.researchgate.net/publication/239391768_ZnCu-vegetative_batteries_bioelectrical_characterizations_and_primary_cost_analyses https://www.researchgate.net/publication/239391768_ZnCu-vege... The zinc is consumed. The copper is not.
- jacknews 6y agoJust use salt water? It's even cheaper and more shelf-stable than potato, and there's quite a lot of it on the planet.
- foobar33333 6y agoOr just use a solar panel. I'm sure with a battery, a single panel could light up my room perpetually.
- kseistrup 6y agoA solar panel may not be economically possible for many people in say Africa.
- foobar33333 6y agoA single solar panel should last you at least 10 years. How much does a 10 year supply of copper and zinc plates cost? I think you would have to stretch to insane lengths to find any case where this kind of power source is economical, sustainable or logical.
- kseistrup 6y agoI have friends who live in shanty towns in Zambia. I can guarantee you that they will be unable to shell out for a solar panel — even if it lasts for 10 years. I don't know about zinc, but copper is plentiful (in fact, they both live in the Copperbelt Province) and they don't have to pay for all 10 years of copper and zinc in one instalment.
- aaron695 6y agoThis is wrong on so many levels it's hard to know where to begin. Poor people don't need small LED lights and it obviously won't charge a phone. Not sure what the whole "the potato is not, in and of itself, an energy source" is rambling on about. Boiling a potato takes a lot of energy, obviously way more than a battery/potato can deliver. Here's the rat attractant battery - https://www.researchgate.net/figure/Potato-battery-basic-composition-and-performance-Potato-Zn-Cu-galvanic-cell-battery_fig1_239391768 https://www.researchgate.net/figure/Potato-battery-basic-com... But jumping to the mathematics I simply don't believe it would be cheaper than a battery I do believe a potato has a lot of energy, I'd assume much much more than a D Cell, but to turn that to usable electrical energy cheaper than a battery I'd be very surprised. I doubt this, but are unsure. [edit] Here's someone who ran their clock for 6 months on a potato (Still not proving either way which is cheaper) - https://www.amazon.com/ask/questions/Tx3AUA83YPS7DMP/ https://www.amazon.com/ask/questions/Tx3AUA83YPS7DMP/
- panchayoooot 6y ago>Poor people don't need small LED lights Huh? Reliable light is one of the best things to provide impoverished areas with, after clean water/food/medicine/sewage. It's one of those things that we really take for granted, but if someone dropped you in the middle of the woods, I bet a headlamp and power source would be one of the first conveniences that you'd ask for. Anyways, like others have pointed out, the energy comes from charge carriers moving between the metals stuck in the potato, not the potato itself. That particular misconception comes up surprisingly often, to the point that it's kind of a running joke in its own right. Portal 2 had a pretty tongue-in-cheek take on the gag.
- aaron695 6y agoYou'll find in practice they can afford a cheap led light and battery what they need is a charger for their phone (And clean water/micro-nutrients/medicine/sewage~=clean water) And wow, potato batteries are a scam. Fool I am. So boiling them won't release more energy to electricity... I guess... I'll need to sit down and work it out. I don't get why a cheaper fluid that doesn't rot won't work ok then. Why is there no web page explaining this Sci Fair scam. Why a potato over salty water? Or a steak. Or a lump of dirt. What's the relationship between a potato having energy and the fact it's used in potato batteries.
- yongjik 6y agoSorry for being glib, but I'm reminded of this comic: https://www.smbc-comics.com/comic/energy https://www.smbc-comics.com/comic/energy
- sedachv 6y agoSee also this bit of Internet history: https://web.archive.org/web/20000815202656/http://world.std.com/~fwhite/spud/ https://web.archive.org/web/20000815202656/http://world.std....
- dang 6y agoDiscussed a little bit here: Potato-powered web server - https://news.ycombinator.com/item?id=3346741 https://news.ycombinator.com/item?id=3346741 - Dec 2011 (10 comments) Spud, potato powered web server - https://news.ycombinator.com/item?id=887160 https://news.ycombinator.com/item?id=887160 - Oct 2009 (6 comments)
- thisiswater 6y agoArticle is complete faff. The potato is not the battery, it is not an energy source, and the article says nothing about the economics of the two plates which are the actual energy source. Don't waste your time.
- nardi 6y agoIf you’d read the article, you’d know that it explains that the potato is just acting as the electrolyte, and it does mention that replacing the zinc electrode is cheap.
- thisiswater 6y agoYes, but the headline says it's a potato battery. It's not. It's a battery with a potato in it.
- overboard2 6y agoBut that's what all potato batteries are.
- leephillips 6y agoThat’s what they want you to think.
- birdyrooster 6y agoLmao (if I delete this it’s bc I don’t like getting downvotes)
- birdyrooster 6y agoNooo I can’t delete!!!!
- leephillips 6y ago
- kumarharsh 6y agoI can't believe the level of disconnect some people on HN have with the "other" worlds. Poor people don't need LEDs? LEDs are the cheapest light source in the long run. The electricity/batteries to run it might be expensive or impossible to get in some places. Check out this gravity-run light source which is "essentially free" and being used in many places. https://youtu.be/Jsc-pQIMxt8 https://youtu.be/Jsc-pQIMxt8
- flatline 6y agoI first heard about it here! Glad it’s still a thing, it’s neat. https://news.ycombinator.com/item?id=9981745 https://news.ycombinator.com/item?id=9981745
- newsbinator 6y agoThey now sell “NowLight”, which you pull on for a minute and it generates enough electricity for 15 minutes of talk time on a mobile phone (or 2 hours of light) https://deciwatt.global/nowlight https://deciwatt.global/nowlight
- hedora 6y agoThat gizmo doesn’t exist any more. Even if it did, the physics don’t really work. A high end bright LED light draws a few watts. Let’s say the LED uses 1 watt, and the gears are perfectly efficient. One watt-hour is 2655 foot-pounds. Assume the weight is 265 pounds with a 10:1 pulley to lift it. You’d have to pull the rope attached to the pulley 100 feet to charge the light to run for one hour, and the device would need to be 10 foot tall. Figure in mechanical losses, and a more realisitic LED, and you end up multiplying the weight, and pully ratio by ten. Now, the weight is similar to a small car, and you pull the rope 0.2 miles for a one hour charge. Make it 5 foot tall, and the weight and rope double again.
- deleted 6y ago[deleted]
- danmur 6y agoI assume I'm just being dense, but if you have to boil the potato, surely that takes a bunch of energy? Or do you burn wood to do that in this scenario
- seltzered_ 6y agoYes. The question to ask in these approaches, from an appropriate technology standpoint, is the locality around creating energy storage and what it would take to maintain the storage device, not just conversion efficiency. For example, one may argue in a given situation one should use an induction cooktop from an efficiency standpoint (and also particulates reduction). Another may argue in a given situation one should use a woodstove if they can source the wood in a sustainable manner and can create maintain the woodstove itself locally. Not asserting a right answer here, just outlining some tradeoffs.
- dwheeler 6y agoObligatory portal 2 snippet: https://m.youtube.com/watch?v=0S3_YJC6OFs https://m.youtube.com/watch?v=0S3_YJC6OFs
- m463 6y agoI think this because an enormous amount of energy was use to smelt the metal from ore. Oxidizing it slowly for electricity is possibly just a weak and inefficient battery.
- wolfretcrap 6y agoIs it viable? We know industrials get power at cheaper rate in some counties, is there any arbitrage possible by making huge batteries like this for residential and commercial use?
- zeristor 6y agoMight I suggest the name: Spud-U-Light?
- getlawgdon 6y agoThe implicit development is the improvement of LED efficiency.