Thats great but i dont want to buy something i want to learn how to make it. I know that is always an option but how fun is it when you just buy something? I'm trying to learn here

Let's try a different approach.
Since you seem to know what you want to do with the wire just tell us the size of the wire (maybe a link) and the length you want for each wheel and I will give you a simple circuit.
The reason I ask for this is because we need to know the resistance of the wire to know how much power the circuit must supply. The resistance is determined by the diameter (AWG) and the length.

 

I think I'd start small and see how it goes with a prototype or series of them. In my experience very few blue-sky designs work great - or at all - on the first shot. But that's fine - that's how you learn what the important variables are. When you don't know what you don't know, you have to collect data. Some factor not yet identified may turn out to be the critical factor. The modern incandescent lightbulb came about after Langmuir's discovery that filling the bulb with inert gas was far superior to the vacuum used by Edison and others before him.

So I'd start with a 10-15A heater. Any car will probably have room to add a 10-15A load without concern for heavier wiring, adding relays and all that. You can just tap into existing circuitry. You'll only have ~150W, but that may be enough to learn if the idea has merit.

Consider upgrading from nichrome to René 41.

I think it's been said before but I'll reiterate: You don't need a temperature-controlled feedback loop to control your wire, you need to control the current through it. A given piece of wire will have some maximum current it can tolerate without getting too hot. Let's say that's 20A. You will operate well below that, say 10A. That amount of power will establish a ∆T between the wire and the environment, and heat will flow from hot to cold.

The temperature of the wire and the ∆T will vary with ambient conditions, but that's OK. You're not incubating eggs, you're melting ice. That requires heat flow, not a temperature. (Obviously you have to have a temperature above freezing.)

How do you control current? There are circuits to control current but you can likely achieve what you need by the clever choice of wire. You'll need a table of wire properties and to do the math to simulate a wire based on your inputs of length and gauge. You might choose a gauge and length of wire that will draw 10A from a 13V supply. Done. If you cannot make self-limiting work, and need to limit the current externally to the coil, we can guide you current-controller options. There are tons available because this is exactly what automotive LEDs need, so you can easily buy one. The circuits can be fairly simple if you'd prefer to build one.

Thanks most helpful response yet

 

Let's try a different approach.
Since you seem to know what you want to do with the wire just tell us the size of the wire (maybe a link) and the length you want for each wheel and I will give you a simple circuit.
The reason I ask for this is because we need to know the resistance of the wire to know how much power the circuit must supply. The resistance is determined by the diameter (AWG) and the length.

I currently have a 20awg spool and need 50 inches per wheel (only doing 2 wheels) so 100 inches total. I am completely open to purchasing a different size (awg) wire if it is more efficient in the circuitry.

 

Playing around with the calculator here (there are many others), it looks like a 50 inch piece of that wire will get too hot (610°F) if connected directly to 14V, causing it to draw 5A.

24 gauge gets it down to 310°F with a 2A draw.

 

Playing around with the calculator here (there are many others), it looks like a 50 inch piece of that wire will get too hot (610°F) if connected directly to 14V, causing it to draw 5A.

24 gauge gets it down to 310°F with a 2A draw.

So theoretically i can use the calculator and purchase the correct awg wire then put a simple switch in the circuit to turn it on and off?

My only obstacle would be testing it, if 310F is too hot or not hot enough i would have to redesign the entire circuit and get different size wire or change the length.

 

I currently have a 20awg spool and need 50 inches per wheel (only doing 2 wheels) so 100 inches total. I am completely open to purchasing a different size (awg) wire if it is more efficient in the circuitry.

Okay, here is the deal.. 50 feet of 20 AWG wire has a resistance of 32 ohms. So at 12 volts it would draw 0.375 amps and generate about 5 watts of heat. About the same as an old fashion 7 watt Christmas tree light. If that is enough you could probably just hook it to your battery with no controls.
Edit:
Sorry, I used feet instead of inches. Go with post above.

 

Okay, here is the deal.. 50 feet of 20 AWG wire has a resistance of 32 ohms. So at 12 volts it would draw 0.375 amps and generate about 5 watts of heat. About the same as an old fashion 7 watt Christmas tree light. If that is enough you could probably just hook it to your battery with no controls.
Edit:
Sorry, I used feet instead of inches. Go with post above.

So if i wanted to up the heat i would have to either get a different awg wire or up the power. My main question is how can I up the power efficiently and easily. Someone suggested early a PWM what would that do?

 

So if i wanted to up the heat i would have to either get a different awg wire or up the power. My main question is how can I up the power efficiently and easily. Someone suggested early a PWM what would that do?

Sorry, I used feet instead of inches so my calculation was way off. So like @wayneh suggested you will need smaller wire. Maybe 28 AWG.
It is still not much power. Maybe like a 10 watt light bulb. Is that enough?
PWM can be used to lower the power, but not increase it.

 

Sorry, I used feet instead of inches so my calculation was way off. So like @wayneh suggested you will need smaller wire. Maybe 28 AWG.
It is still not much power. Maybe like a 10 watt light bulb. Is that enough?
PWM can be used to lower the power, but not increase it.

So overkill it then regulate it down? Does the pwm overheat?

 

So overkill it then regulate it down? Does the pwm overheat?

It may be a little trickier than that. I think you need to strike a balance between total power and maximum wire temperature.
It is difficult to guess how much power would be needed for what you want to do. Maybe 100 watts or more??
PWM controllers are very efficient.

http://www.ebay.com/itm/like/131584257621?lpid=82&chn=ps&ul_noapp=true

 

20AWG -- 0.65Ω/ft -- ~5Ω/100" -- ~34W @13V (17W per wheel).
24AWG -- 1.65Ω/ft -- ~13Ω/100" -- ~13W @13V (6.5W per wheel).
Using either gauge is not going to upset your alternator and is most unlikely to overheat. On the contrary, I suspect those wattages will be inadequate for shifting any appreciable build-up of ice/snow.

 

So maybe this would work for 110 watts.
3 sets of 10 inches in series. Then 9 more just like it in parallel.
Using 30AWG wire.
From @wayneh handy calculator 11 watts per each set.
Do you think 110 watts is enough? If not we may need another way as the wires will now only be .2 inches from the next wire.

 

It may be a little trickier than that. I think you need to strike a balance between total power and maximum wire temperature.
It is difficult to guess how much power would be needed for what you want to do. Maybe 100 watts or more??
PWM controllers are very efficient.

http://www.ebay.com/itm/like/131584257621?lpid=82&chn=ps&ul_noapp=true

Ok i think i understand i should find my max wire temp and power design it around that then use the pwm to scale it down.

Do you have any recomendations for a reliable PWM i would like to purchase from amazon. Prime would be awesome!

Thanks

 

Ok i think i understand i should find my max wire temp and power design it around that then use the pwm to scale it down.

Do you have any recomendations for a reliable PWM i would like to purchase from amazon. Prime would be awesome!

Thanks

You got it.
http://www.amazon.com/uniquegoods-U...TF8&qid=1457553069&sr=8-4&keywords=pwm+driver

 

Those are around $5.00 on ebay, PP.
Max.

 

You got it.
http://www.amazon.com/uniquegoods-U...TF8&qid=1457553069&sr=8-4&keywords=pwm+driver

So as long as i dont exceed 20amps on that i should be fine?

Today just to test it out I created a parallel circuit out of the nichrome wire i had (spot welded together) and it seemed like the sections that werent spot welded heated up much more than the rest of the parallel why is this?

 

Draw the circuit.
Don't you have any idea how to work with electrical circuits?

 

Draw the circuit.
Don't you have any idea how to work with electrical circuits?

Not in the slightest, honestly thats why i am here for help.

Will post a picture when i'm home

 

i should find my max wire temp

That's going to be tricky. It will depend greatly on the type and thickness of the material it's embedded in, as well as wattage and ambient temperature.

 

Seems to me this is a solution looking for a problem. Drilling mounting holes and wire feed through holes will do much more damage to the vehicle than the built up ice and snow.