# Resistance based heater

Discussion in 'The Projects Forum' started by ricky diaz, Mar 28, 2015.

1. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
Hi guys, this time i´m working on a small fan heater for an incubator (chicken incubator), i´ve found many ways based on NiCr wire, but thinking allways find other ways is always good help, so in my case i have no acces to NiCr wire unless some of my musician friend give me some of theyr guitar strings, which i probbably will not have since this is important for them, so i was thinking on a heater based on resistance, i´ve found some basic ideas on the web, but asking the right people always come handy, so in my case i need about 80 watts heater (same as a standar 110v bulb light), and i´m thinking to conect this to a 12 to 17 volts supply, so wich calculation do i have to apply to make it possible?, if 115Volt is better i could do too (not prefered since it is dangerous), any idea will be welcome guys, cheers.

2. ### MikeML AAC Fanatic!

Oct 2, 2009
5,450
1,066
How about some 12V auto tail light lamps?

Voltage is safer. A normal brake light is about 3A @12V, so P=IE = 3*12 = 36W.
The side marker lamps are ~1A, so 12W each.

3. ### Dodgydave Distinguished Member

Jun 22, 2012
4,979
744
12V bulbs @ 21W x 4 = 84W,
you can run it from an old Atx psu,

or use two 60W mains bulbs, with a light dimmer.

4. ### wayneh Expert

Sep 9, 2010
12,103
3,038
I agree with the lightbulb approach - it's a time-tested solution. One benefit is visual feedback showing when the heat is on. If you don't see it cycle once in a while, you know there's a problem.

5. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
Yes, i agree with all of you about bulb heating option, in fact i´m running one right now but every time it´s more and more dificult to find bulbs since the new regulations that comes to kill them because of the power consumption wich is more a bad publicity i think, even 12V car bulb are becoming HID or LED, so every time is more real that the day will come to they disapear from the market i guess, despite the price is now higher than never for the few available. I still loking forward to find some NiCr wire for the coil making just to have couple more spare options to use inside the incubator, remember i have doulble thermo check inside so i allways watch around whats going on in case something fail i can switch to any option for heating.

6. ### Marcus2012 Member

Feb 22, 2015
349
26
Hi

Along the line of bulbs, could you use the ceramic heating bulbs that are used for reptile enclosures?

Like these ones
Swell ceramic heater emitters
there may be some on ebay under ceramic heater emitters.

ricky diaz likes this.
7. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
In fact that is a very nice product Marcus, but not available in my country, remember here there are people from around the world, in my case it is very dificult to find many things like that, so i have the necesity of make it by my self.

8. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
That product shown by marcus is the same thing i´m trying to do with a ceramic resistance array, it is exactly the same.

9. ### MikeML AAC Fanatic!

Oct 2, 2009
5,450
1,066
Car lamps are going to be around for a long, long time...

How about just using 10W 15Ω cement resistors, like these

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10. ### #12 Expert

Nov 30, 2010
16,278
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We had a vacu-former thread a month or 2 ago. The nichrome information was all in that thread.

11. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
Thats the type i want to use and i have available at the shop, how could i calculate to produce around 80 watt heat?

12. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
could you refer me the link?

13. ### wayneh Expert

Sep 9, 2010
12,103
3,038
Ohms Law: V = I•R. For a resistor, this can also be written as ∆V = I•R where the ∆V is measured across the resistor. The power dissipated is P = I•∆V = I(I•R) = I^2•R. Units are volts, amps and watts.

14. ### MikeML AAC Fanatic!

Oct 2, 2009
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If you use 15Ω resistors, each one will dissipate E^2/R = 12*12/15 = 144/15 = 9.6W

To get 80W, put 80/9.6 = 8 of them in parallel.

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15. ### wayneh Expert

Sep 9, 2010
12,103
3,038
Oh yeah, this isn't homework. Full answers preferred.

Nov 30, 2010
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17. ### ricky diaz Thread Starter Member

Feb 16, 2015
71
7
Thanks Mike, i really apreciate your help, now i will do my own calculations based on the supply i will use, cheers all guys.