Thread: alligator clips.

won't work

G'day rgum,
What you're dealing with here is an infallible principle called Ohm's law (Where an Ohm is where a Volt is Currently Living)
Ohm's law states that Power (watts) = Current (amps) x Voltage(Volts)

Say its a 1000 Watt Toaster
at 240 Volts 1000 = Current x 240
therefore the current required is 1000/240 which = 4 amps roughly

at 12 volts
1000 = Current x 12
the current required to produce a 1000 watts is 1000/12 which = 83 amps roughly.
You're battery is not going to like it.
sorry

Hi rgum,
Even if your car battery will handle 83 amps, as watson pointed out, it still won't work. Since a toaster is a resistive load then another part of ohms law prevails. That is:
I=V/R, where I is current (amps), V is volts and R is resistance (ohms). Since you will be trying to connect the toaster to 12V (and DC I might add) instead of 240VAC then all you will be doing is dropping the current, and therefore the power (P=VI).
In a nutshell, it won't work (thanks echnidna).
To use a 240VAC toaster on a car battery you will need an 12VDC to 240VAC inverter.
Cheers,
Peter

Sorry guys, there is only one Ohms Law, and it tells us that the current (I Amps) flowing in a circuit is equal to the voltage (V Volts) divided by the resistance (R Ohms)

so I =V/R
It can be transposed by multiplying both sides by R so IxR = Vx R/R or IxR = V or V = IxR.
It also can be transposed by dividing both sides by V so that I/V = (V/R)/V so I/V = 1/R so by inverting R=V/I.

So the three ways that Ohms Law can be expressed are:

a, I=V/R
b, V=IR
c, R=V/I

Also by definition the power disipated in a component (P Watts) = the voltage accross the component times the current flowing through the component.

So P = VxI
substituting a, P = VxI = VxV/R = Vsquared/R
substituting b, P = VxI = IRxI = Isquared x R

Unfortunately, this is only a correction of mislabled facts, and the result is still the same. Your household toaster (say rated at 2400W) does a nice job of singeing your toast, and draws 2400/240 = 10 Amps from the socket.

To replicate that effect exactly from 12V you would still need an element disipating 2400W, but it would draw 2400/12 = 200 Amps from the battery, almost as much as a starter motor cranking the engine. Plus it has to have that level of current for 3 to 5 minutes to cook the toast just right.

You are slightly luckier with lights. While the same laws apply, most classes of 240V lights have 12V variants, e.g. normal incandescant, flouro, halogen are all available in 12 or 240 Volt varieties, but for equivalent power output, the 12V variety will draw 10 times the current that the 240 V would.

Yep!...True stuff....I never should try to simplify an explaination.
Same effect.....as Echidna said......."won't work"

rgum, this'll teach you to go to sleep during double periods of physics on Friday afternoons! There was also v = u + at but you don't need it just for now

Mate, don't be discouraged. Just lay your bread on the exhaust manifold 5 minutes a side while the engine is running. naturally greasy, so you won't need butter.

A single burner gas stove (the ones with the cartridge) and a mesh toast cooker does a great job. Quick and easy and very portable.

Do not modify the toaster. Buy a cheap 240v petrol genny

Welll?....I'm all up to date on my electrical maths. Sheeeessh!

Is it soo hard to make toast these days, on the an open tailgate?

Ahhh.....but! My manifold is clean and I will need to butter the toast.

An inverter you say. Ok I'll look it up on ebay.

Lets keep it simple lads. NO MATHS PLEASE!!!!! Sais a little about me huh?

A car batt wont supply enough power to a little modern electrical toster....right?
So get an inverter with a pwr point on it .....right?

Oh yeah..... Has anyone got a caravan stove they wanna get rid of?

Bloody hell......all those formulas and theories. "Shocking "I say, ha he
But I have to be " positive" about this , not " negative ", ha he ha.
Oh stop.... paaaalease.
Now I'm being a punny bugger, ha he.

Can I also aligator clip a spot light off a battery...car batt? A batterey in the back of my ute.

Cheers Tony.

An average "2 slice" toaster uses about 700W to 1100W of power. If you are thinking of using an inverter, try this website to give yourself an idea of the prices. A 1kW inverter will cost about $500.

http://www.invertech.com.au/home.htm

Dont forget rgum that even if you get an inverter you will still be needing to usse the same amnount of battery power to give you the required result.
Sadly in electrical terms you get nuthin for nuthin.


I have a house we run on battery power charged from a wind turbine and SWMBO is banned from using the toaster. I bought her 2 of those mesh thingys for 50c ea at a garage sale.

One of my pet hates is using 240volts perfectly produced for a crappy resistive load when we have a lpg cooktop to provide the energy. Similarly the electric kettle / jug is out.


The best move is for the wire thingy on the gas flame.

Peter

Originally Posted by rgum

Oh yeah..... Has anyone got a caravan stove they wanna get rid of?

if olny I had read this thread a few days ago, yes, I did have a caravan stove that I just got rid of, $2,200, it came with a gas bottle and a caravan )