AC or DC Heating of a wire

Using Arduino Project Guidance
#1

Hi,

I am working on a project that the goal is to heat a piece of 20cm wire to 100 degrees C as fast as possible (100ms) and the power source being a 12V lead acid battery. The 20cm wire has a resistance of ~1 ohm. My question is: - What heating method would be more effective? AC or DC? DC would be like shorting the battery with a MOSFET switch. AC would be like using an inverter. (note: the accompanying electronics should be small size) - What do you think of a step up converter and shorting the wire with a higher voltage?

Please share your ideas of what would work best and more effective (fastest)... Thanks

#2

Shouldn't matter if you use 12V DC or 12V RMS AC.

The higher the voltage the more current you can shove through a given resistor. The more current, the more wattage and the faster it will heat.

#3

Even a small 12V VRLA battery will deliver above 125W into a 1R load, at least for a minute or so. I think your wire, in air, would reach 100C faster than 100ms. How are you going to measure its temperature so quickly?

#4

Why 125 and not 144 watts?

…R

#5

A fully charged 12V battery has an open circuit voltage around 12.5V. If you put a load on it, the voltage will drop. You don't say the capacity of your battery, but to a 7AH alarm battery, 12-ish amps is a large load. Its fully charged voltage might drop to the 11V range to deliver that current. If the battery isn't fully charged, then the voltage will sag more.

A pair of fully charged 400AH L16 batteries would not even notice a 12-ish amp load and would deliver 12.5A at 12.5V no problem.

#6