Lemon Battery Experiment confusion

Discussion in 'The Projects Forum' started by Lacspac, Feb 7, 2010.

  1. Lacspac

    Thread Starter New Member

    Feb 7, 2010
    My son & I are attempting the Lemon "battery" experiment (6 lemons connected in a series hoping to light a bulb) and we are baffled by the conclusion. After linking 6 lemons (using gator clip electrodes; 14 gauge copperwire & galvanized nails in each lemon) we were able to detect 4.5V! Great, but why won't our bulb light? We tested each bulb with a 1.5V battery and they work fine. We have tried a variety of tiny bulbs (ie. small bulb in science kit & diodes). We are stumped and if anyone can shed some "light" on the situation that would be greatly appreciated. It would make his science fair project that much more exciting for him.

    Thank you,
  2. bertus


    Apr 5, 2008

    What kind of lightbulb are you using?
    What voltage and what current does it need?
    The lemon batteries can not deliver much current.

  3. Audioguru

    New Member

    Dec 20, 2007
    There are many Lemon Battery experiments on the internet. They all say, "The two lemon batteries combine to produce a voltage of 1.788 volts. This combination still does not create enough current to light a small light bulb."
    They show the battery dimly lighting an LED.

    An incandescent light bulb uses 90% of its input power to make heat and only 10% of the power to make light.

    Maybe you can connect many (10 to 100) lemon batteries in series-parralel to make enough current to light a bulb.
  4. retched

    AAC Fanatic!

    Dec 5, 2009
    Instead of lighting a bulb, why not use a multimeter and show the audience how the voltage goes up with each connected lemon?
  5. Wendy


    Mar 24, 2008
    Instead of a light bulb, how about an LED? You will still need a lot of lemon batteries, but a fraction of what a light bulb would need.

    The color red is the most efficient, 2 batteries in series will cause some light. Every 2 after that put in parallel, and the LED will get a little brighter.

    The problem you are fighting is the current from each is just too low to be useful. You could use larger area of metal disks (I'm assuming you're using coins), the extra surface area would increase the current. This is the same as using multiple batteries.

    You might also think of using a clock, since they are low current devices too.

    Another alternative is to charge a capacitor, which will flash a light bulb when connected to it. This would demonstrate storing energy for use in a high energy application later.
    Last edited: Feb 8, 2010
  6. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    I'd guess the current available is at least partly proportional to the battery 'plate' areas - can you use strip metal rather than wire in the lemon, or lots of separate strands connected together to give more surface & reactive area?

    You may still not light a filament bulb, but the LED will be brighter.
  7. KL7AJ

    Senior Member

    Nov 4, 2008
    I had a lemon clock that ran for about 6 months on a pair of lemons.