In this day, age and social context it is blindingly obvious just how necessary electricity is. It has become apparent that people are prone to disappointment should their electrical devices run out of charge when they are away from traditional sources of power, without a charger.
As you may or may not recall however from primary school science experiments, it is possible to create a basic battery out of citrus, or most other fruit and vegetables. (Because of the high acidity, citrus works best though.)
It is, however, not the most efficient battery available, with a standard lemon producing about 0.9 Volts and 0.0003 Amps when connected via readily available zinc and copper electrodes (a bit of metal that you stick into the fruit.) Thus, four or five lemons connected in sync are sufficient to run a small LED (Light Emitting Diode), lasting around five hours or so. Apparently two lemons can run a small digital clock.
Sadly, this seems to be as far as people/scientists go, with a few theoretical observations being such that to run a flashlight bulb would require some 5000 lemons. A halogen bulb requires 37000.
In this, a brief and inaccurate exploration into the more practical and impractical uses of the humble lemon battery et al, we shall explore and theorise at a more exciting level.
Firstly, to charge your phone. Well if you happen to be stranded in an orchard and need to charge your phone, you’ll need to produce about 2 Watts (Voltage times Amps) and each lemon will give you about 0.00027 Watts. Therefore you’ll need 7400 lemons in sync operating for around three hours to fully recharge your phone. Oh, and you may want to add a resistor too, as 6660 Volts would be flung unintentionally at your phone otherwise all at once. Moral: make it last.
On the high power side of things, you’d need about 500 mA of direct current to electrocute someone. That’s about 1 666.7 lemons. But you’d need a voltage of 2000 Volts ideally, so 2300 lemons to be ‘safe.’ But if you wanted to merely feel an electric shock , 500 lemons should do. However, this would create quite a large and painful Amp value (150mA).
Ironically, to operate all the magnets in the CERN’S Large Hadron Collider, you’ll only need 16 240 lemons. This is because each magnet is cooled to superconducting temperatures, resulting in a massive current. Also it costs about $100 000 to electrically run the darn thing each day, and if you estimate that there are about 7 moderately large lemons in a kilogram, you’d need 2320 kilograms. At around $4 per kilo that equals $9280 for a five hour stint. $46400 for a 25 hour lemon-induced atomic collision spree. I detect value.
In summary, you’d need almost four times as many lemons to charge your phone than to kill someone, and if you wanted to charge three phones, you could run the world’s largest particle accelerator on a shoestring budget instead.
Now. It is possible to make a HUMAN battery through similar processes. So let’s consider a practical situation. There is a point in the underwhelming movie Dead Snow where two characters, stuck in the middle of nowhere without electricity suddenly ‘remember’ they have a mobile phone but it soon goes flat. The cottage they are in is surrounded by hordes of up to 300 Nazi Zombies. The problem: can you recharge the phone using a human/zombie battery system?
Let’s be optimistic and assume each zombie can produce .5 of a Volt (when the people at the end of the chain touch copper and zinc electrodes (and that they can still sweat – as the salt is what makes the human/zombie battery work). Holding hands, and being insulated from the ground by their boots, they would form a chain and produce about 150 Volts. Let’s also assume they had been eating/bathing in citrus, or something, and had an Amp flow of 0.0003 each. This would produce 0.0045 Watts of power! Nowhere near enough to charge it in the usual three hours. (But a lot of quality standing-around time holding-hands and if you persisted – I estimate it would take 55.5 days.) Three Germanic cheers for those involved!!
It seems, like those at CERN, I have too much time on my hands.
P.S. Electrocuting someone would cost around $1300 in lemon batteries. Don’t try this at home. It’s too expensive.