Lemon and salt water batteries

Our lemon tree, two of our munchkin cats who love the lemon tree and 5 lemons.

A 5 cell lemon battery was built and tested running a blue LED.
You need lots of lemons to make it a success.
I used 5 lemons in series but to really make it go well, you need at least 20 or 30 lemons in series parrallel strings of 5 at a time, to get a current of about 15 mA.
Each lemon supplies about 0.9 volts between a copper electrode (positive) and a plated steel screw (negative). Total 4.5 Volts.
It drops rapidly to the zenervoltage of the blue LED at around 2.5 Volts and a current of below 1 mA.
For a red LED 4 lemons in series will suffice.

The saltwater test has a better current and with 4 cells in series gave 3 Volts open circuit and 1 to 2 mA for the LED.
Open circuit Voltage 3 Volts, loaded 2.4 Volts.

It definitly proves the fact that a large surface area is needed for the electrodes to be in contact with the acid or salt to give a reasonable current.
The internal resistance of the path of the electrons through the conducting medium is relatively high.

Compare for example a 12 Volt car battery in size with a 12 Volt truck battery. Same voltage but for the truck battery a very large current compared with that for a car required for starting the engine.

LED data:
Red led 1.7 Volts 15 mA for good brightness
Blue led 3.1 Volts 15 mA for good brightness
( most led's are rated for 20mA continuous )

The reason I put this experiment up on YouTube is that my 10 y.o. daughter wanted to know it for a school project, that if you could get power out of a lemon.

Category:

Howto & Style

Tags:

• lemon
• battery
• salt
• water
• experiment
• LED
• blue
• munchkin
• cat
• tree
• cell

[crazyJ1678]

what can this charge?

[RODALCO2007]

@crazyJ1678 It was used as a battery experiment for school.

The power output is very low.

[winner1215]

Do you feel the current when you adjusted the screws?

[RODALCO2007]

@winner1215 No. the voltage is less than 4 Volts and the current only a few mA's

[yoshi713467713]

im doing a project at school, this really helped THANKS A LOT : D

[RODALCO2007]

@yoshi713467713 Thanks for your comment. Glad it helped.

You need a lot of lemons or large electrodes to get any reasonable current to get a couple of led's going.

[TheAFlyer]

Thumbs up if CX brought you here

[RODALCO2007]

The led runs for about 5 to 8 hours in this set up, main problem is minor corrosion at the terminals in the lemon which reduces the current flow and less power to the led.

With a red led it will last longer. try it out

[winner1215]

@DJMC5ive Thank you :) But I already learned this a few years back, but thanks for the warning!! Good man, have a blessed day (thinking you are a Christian lol)

[DJMC5ive]

@winner1215 before you get to crazy with that back thing, learn how it would effect you, as in how electricity could disrupt your heart's rhythm. Large amounts flowing through your foot might not, but even little amounts across your upper torso, could.

[winner1215]

@RODALCO2007 Well what volts can you feel without harming your heart?

Cause my friend has a back problem and uses one of these volts therapy thing and it helps a lot. Sooo, lol I wanna know :3

[ms63129]

For an experiment like this, you can also use brighter LEDs for more brightness; I have had LEDs that light up pretty well with well under 1 mA of current, also a good trick if you use an LED in a battery powered circuit; no use wasting 10-20 mA for a "on" indicator, I recently used such an LED at 100 microamps (the circuit itself draws 2 mA from a 9 v battery) with high visibility (HB LEDs tend to be clear/directional but this one was diffused, so you don't have to directly look at it).

[TheAntTony96]

I wonder if you stick some wires in luke...how much energy will it have?

[doom53104]

You should try putting the two together.