Wattage Calculator for Hot Water Heater Elements - Home Brew Forums

 Home Brew Forums > Wattage Calculator for Hot Water Heater Elements

05-12-2008, 03:53 AM   #1
sanders5x
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Nov 2007
Fargo, Nd
Posts: 35
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Does anyone know of a calculator for water heater elements? More specificly I have a 240V 4500Watt model and am wondering what it would take at 110V. I am also wondering if it would take different wattage at say 220v thanks.

05-12-2008, 04:00 AM   #2
Yuri_Rage
Gritty.

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Jul 2006
Southwest
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V = IR, and P = IV. That's all you need to know.

4500W = I x 240V
I = 4500W / 240V = 18.75A

240V = 18.75A x R
R = 240V / 18.75A = 12.8 Ohms

220V = I x 12.8 Ohms
I = 220V / 12.8 Ohms = 17.1875A

P = 17.1875A x 220V = 3781.25W

Same math applies for 110V.
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05-12-2008, 04:09 AM   #3
sanders5x
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Nov 2007
Fargo, Nd
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Quote:
 Originally Posted by Yuri_Rage Read my edit above. All the unknowns can be calculated.
sweet thanks Yuri, gonna build me a HLT, and I did the stainless welding myself. They dont look as nice as yours tho

05-12-2008, 04:11 AM   #4
Yuri_Rage
Gritty.

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Jul 2006
Southwest
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Bet you're halfway through the algebra now, so this will piss you off:

http://www.sengpielaudio.com/calculator-ohm.htm

Just found that...enter two knowns, it'll calculate the rest.

Good luck with the brew rig - it's a fun build, isn't it?!
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05-12-2008, 04:35 AM   #5
sanders5x
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Nov 2007
Fargo, Nd
Posts: 35
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Quote:
 Originally Posted by Yuri_Rage Bet you're halfway through the algebra now, so this will piss you off: http://www.sengpielaudio.com/calculator-ohm.htm Just found that...enter two knowns, it'll calculate the rest. Good luck with the brew rig - it's a fun build, isn't it?!
Welding the stainless was really fun, and cheap!

05-12-2008, 12:37 PM   #6
Funkenjaeger

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May 2007
Nashua, NH
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To skip a few steps and condense all Yuri's math down to a single equation for this particular case:
P=(V^2)/R
P2=P1*(V2^2)/(V1^2) where P1,V1 are the rated power & voltage (4500 &240), and V2 is the voltage you want to run it at.
P2=4500*(120^2)/(240^2)=1125W

05-12-2008, 09:41 PM   #7
sanders5x
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Nov 2007
Fargo, Nd
Posts: 35
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Thanks guys!!

05-13-2008, 03:36 AM   #8
sanders5x
Recipes

Nov 2007
Fargo, Nd
Posts: 35
Liked 2 Times on 1 Posts

I was working on my control box today:

[IMG]http://www.***************.com/home2/galleries/5/box1.jpg[/IMG]

Anyone got a couple of feet of t-type thermocouple wire ?

04-18-2014, 06:55 PM   #9
mattyb85
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Jan 2012
Wakefield, Ma
Posts: 272
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Quote:
 Originally Posted by Bobby_M I have a spreadsheet that calculates the stuff for you.. http://www.suebob.com/brew/elementcalc.xls
Bobby,

Do you still have this spreadsheet?

04-19-2014, 12:33 AM   #10
Bobby_M
Vendor and Brewer

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Aug 2006
Whitehouse Station, NJ
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http://www.brewhardware.com/docs/elementcalc.xls

Instructions: Fill in the three blue boxes...
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