Tree power?

ka1mwp said:

https://www.electro-tech-online.com/custompdfs/2008/04/press_release-1.pdf

Maybe a repeat in here, but interesting.

Chuck

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Sorry, but it's a complete load of utter rubbish!.

It's just the dissimilar metals in a lemon all over again!.

lemons?

it didn't have anything to do with lemons...just trees in general..
I never ended up following this, I use the company for thier HV tx's.
They got a grant and farmed it out to I think MIT or someplace last I heard..

ka1mwp said:

it didn't have anything to do with lemons...just trees in general..

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It's usually done with lemons, you place two dissimilar metals in a lemon and the chemical reaction generates a small amount of electricity and destroys the electrodes - the tree sap works in the same way, it's the metal being consumed that generates the small amount of electricity.

Ken has the right idea.
With some of these big trees you could put a pole to the top and use the wind to pump water or compress air. There would be energy in that, maybe even a few watts.

Exactly Nigel, I've been trying to explain this all along. The energy comes from the metals, not the tree. You always get less energy out than what was required to extract the metals from their ores.

Not many oranges this year, maybe 30 on the whole tree. These are about as big around as my thumb. Couple of months, and I should be able to try a joule thief. Figure four electrodes, thick copper wire and zinc plated screws.

... Tree Power?
1. Cut down the trees
2. Burn the trees
3. Use the heat to boil water to drive turbines.

Hahaa... how un-environmentally friendly, greenpeace is after me now...

That would be better, at least it's carbon neutral.

I remember seeing some supposidly water powered digital clocks in a camping shop claiming they are environmentally friendly. I wonder how long they would have lasted until the electrodes totally corroded away. It's of course rubbish, the energy to power the clock was still comming from fossil fuels used to separate the electrode metals from their ores.

Try one potato instead of lemon, properly cut in small cubes, (each one in an appropriate recipient) allows for easier series/parallel combination testing.

It works.

I don't think the message got to you.

The electrode metals provide the energy, and are fundamentally consumed in the reaction, because you can't get energy for free. The lemon or potato acts as an electrolyte and is just a carrier medium. Salt water works some too. Acids/bases work better than salt water, whether you need an acid or base depends on the plate material.

When the battery is run down, washing out the electrolyte (lemon juice) and replacing it with a fresh lemon will not restore power. To restore the batt would mean replacing the consumable plates.

So unless you can come up with a tree which refines copper/zinc/lead/etc into a higher energy state, it won't be the basis for a battery.

Oznog said:

I don't think the message got to you.

The electrode metals provide the energy, and are fundamentally consumed in the reaction, because you can't get energy for free. The lemon or potato acts as an electrolyte and is just a carrier medium. Salt water works some too. Acids/bases work better than salt water, whether you need an acid or base depends on the plate material.

When the battery is run down, washing out the electrolyte (lemon juice) and replacing it with a fresh lemon will not restore power. To restore the batt would mean replacing the consumable plates.

So unless you can come up with a tree which refines copper/zinc/lead/etc into a higher energy state, it won't be the basis for a battery.

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I do understand that the metal is the consumable, but the electrolyte does need to be replaced or refreshed as well, long before the metal is all used up.
The idea was to use the fruit on the tree. The acid is pretty weak, and the voltage/current low, figure the metal should last at least one growing season.

Toxic Copper

Beware of sticking anything copper into the living tree as it will kill the tree.

Super_voip said:

Beware of sticking anything copper into the living tree as it will kill the tree.

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Thought about removing the tree many times, bad location, not the best oranges... Anyway, I'm not thinking about inserting anything into the wood, just the fruit. Going to be a couple of months before any are big enough.

Funny thing though, I was going to buy a few oranges last time I was at the store. The price was outrageous, and I noticed the little sticker said California on it! They shipped them clear across America, to the state that grows the most citrus fruit. Maybe they have a longer or later growing season on the west coast. Couldn't see spending 75 cents each, just to play with. I can wait.

California is further north so I doubt they have a longer growing season. My guess is that the oranges come in to season at s different time than they do in Florida.

For example, here in the UK, we can get cherries come in to season in July. If we want them in June we import them from southern France and if we want them in September we get them from Norway.

We don't grow much fruit here anymore, most of it comes from France, Holland, Spain, etc.

But here in California, it seems that all the orange juice comes from Florida.

mneary said:

But here in California, it seems that all the orange juice comes from Florida.

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The orange is always better from the other side of the hill

it's funny here in cambodia they call it oranges but actualy they are sweet limes. no kidding

they look green with yelow flesh and are sweet

Robert-Jan

They're probably oranges.

If you grow oranges in a very warm climate where the temperature never drops below, about 15°C, then they'll never turn orange, they'll stay green but still tase sweet.

HarveyH42 said:

I do understand that the metal is the consumable, but the electrolyte does need to be replaced or refreshed as well, long before the metal is all used up.
The idea was to use the fruit on the tree. The acid is pretty weak, and the voltage/current low, figure the metal should last at least one growing season.

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Not exactly. Some chemistries like NiCd don't consume the electrolyte at all in the reaction! Batteries aren't designed to need electrolyte replacement before consuming the plates. Lemons dry out and the complicated chemistry of what's in the juice makes a load of chemical crud out of it, so replacement is helpful, but there's no economic value to using this free-growing yet crummy form of electrolyte.

The electrolyte is probably affected- consumed- in the cu-zn lemon battery, but it's beside the point. One could buy a half gallon of sulfuric acid drain cleaner for $4 or so that would fill dozens and dozens of these. Copper and zinc, however, cost quite a lot, largely because of the energy required to refine them into a pure metal state (which you will be draining back out when consuming them into another state). The electrolyte is not the cost here.

Potato/lemon clocks and batteries are cute science fair projects, but quite misleading. Plants store energy as sugars/carbohydrates, but none of this stored energy is used in this battery. The energy comes from the plates and salt water works ok at being the electrolyte too. Thus it cannot be used to "grow" a battery, not in this concept anyways. It is misleading. There ARE living battery systems, certainly. The electric eel being a remarkable example. There is heavy research into making a bio-battery for pacemakers and such that is actually a fuel cell which indeed uses the carbohydrates in the bloodstream as fuel. However, it's a real complicated field. I don't know if there's anything an amateur could put together to make a current that works on the fuel cell principle apparently promised (but not delivered) in the lemon battery.

Citrus trees are just very common here in town. I was just hoping to throw together something small, simple, and most importantly cheap. That I could just shove into a fruit hanging on mine (or any of the many I pass while walking the dog), and light an LED, maybe flash or something.

Unfortunately, seems like I need a large surface area on the plates to generate even enough power for a joule thief. Pretty sure zinc plated screws and thick copper wire won't be enough. The plates will likely get coated with crude and fail within a few days. Will probably still give it a shot though.

Slightly less cute, but much more practical, is to use a small single cell and drive an led with a joule thief. Hollow out an orange and hide it in there. Much longer life.