Thread: How does the concentration and amount of ions in the electrolyte affect voltage? How does pH of the electrolyte affect the battery?

[someguy543]

I accidentally posted this in general discussion, I'm reposting here because I'll probably get more response here.

How does the concentration and amount of ions in the electrolyte affect voltage?

How does pH of the electrolyte affect the battery?

Does the pH level affect battery life?

Does pH affect generated voltage?

If not, what factors affect battery life?

Why are fruits with higher acidity preferred when making fruit batteries?

This is for our homework on batteries.

[Flick Montana]

First, the way the electrolyte dissociates in water determines how strong it will be. The best electrolytes (strongest) will dissociate completely. This allows their charges to be carried more efficiently.

The relationship between pH and conductivity should be relatively weak. What is important is the composition of the electrodes and the relative ion concentration in the fruit itself. As for pH relation to better batteries, we know certain basic solutions make for strong electrolytes as well. The big difference is that the acid in citrus fruit makes for a good electrolyte, is cheap and easy to obtain, and isn't dangerous.

Lemons are great battery with copper and zinc electrodes. If I remember my middle school experiments properly, just a couple of them can power an alarm clock.

[someguy543]

What is important is the composition of the electrodes and the relative ion concentration in the fruit itself.

Thanks for the response I was getting pretty hopeless.
So more ion concentration would equate to better conductivity?

So am I getting this right:

More ion concentration = better conductivity = less resistance = more current?

[Flick Montana]

Think of it more as a stronger electrolyte will be a better medium. You have to consider the acids in the fruit.

Basically, the acid reacts with the metal cathode and anode. The electrons that travel through the solution in the fruit can be better carried by strong electrolyte solutions that completely dissociate into ions. It is the interaction of the electrons moving between the cathode and anode that creates the electrical current. The more efficiently the electrons are carried, the stronger the current.

[Zwolver]

How many lemons would you need to produce lethal voltage and current?

[Harold14370]

How many lemons would you need to produce lethal voltage and current?

This is not an easy question to answer, since the body's resistance varies, and lethal shock current depends on the organ being affected.
According to this site, a lemon produces .00027 watts at 0.9 volts.
Lemon battery - Wikipedia, the free encyclopedia
According to this site, currents between 100 and 200 mA are lethal.
Electrical Safety: The Fatal Current
According to this site, the human body's resistance is typically about 1875 ohms at about 100 volts.
Electric shock - Wikipedia, the free encyclopedia

Taking this information together we get
Power (I^2*R) of a lethal shock is about (100/1000) amps*(100/1000) amps *1875 ohms = .01*1875 = 18.75 watts.
18.75 watts/.00027 watts per lemon =69,444 lemons.

[Flick Montana]

Death by 70,000 lemons. Now THERE'S a science project!

[Zwolver]

Death by 70,000 lemons. Now THERE'S a science project!

I'd say, dropping them on someone would cause death much easier and quicker. Or juice them, and make someone drown in them. Or make someone eat 50 lemons, that would be a cause of death probably..

Hehe, still good to know.. So with enough time, and lemons, you can make lemonade..

I don't know if it's illegal to touch someone with lemons... is it?