HarveyH42

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.

Super_voip

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

HarveyH42

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.

Hero999

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.

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mneary

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

rjvh

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

Hero999

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.

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Oznog

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.

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I thought what I'd do was I'd pretend I was one of those deaf-mutes.

HarveyH42

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.

mneary

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.

rjvh

That's cheating

you can also use chrismas lights and burry the cable

Robert-Jan

HarveyH42

It was suppose to be a small, cheap, and highly portable device that I could quickly install anywhere in town with a citrus tree. A fully charged battery will run down in about a week, three days with a fading RGB. Anyway, the rainy season is here, so expect some rapid growth from the oranges. My dog knock off a small pineapple yesterday (the best one, of course). It's at least 2 months premature, so going to experiment on it. Hope the other two make it to the end of summer.

mneary

Before getting your hopes up, it would be a good idea to clock the amount of energy that you'd expect from a couple of electrodes in a citrus fruit. I haven't tried, but my guess is a AAA battery will be at least 10x better.

HarveyH42

That's pretty much the challenge. The Joule Thief will light an LED, with as little as 0.3 volts. The AA and AAA batteries have a very limited life. The citrus fruit battery should produce until the electrodes are covered in oxidation crud. How long will they last? Have to wait and see.

Hero999

A single 20A SLA cell shoud keep an LED going for over a month but you'll need to make some sort of low voltage disconnect to cut the power when it drops below 1.75V or your cell will die.

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