Quote:
Originally Posted by Deezler
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After ~2 hours in my 44 degree garage, the coolant temp is up to 92. Meh, not bad I geuss. But I was hoping for a little more impact. Any EE's here? I bought a 240V unit and simply wired it for 120V. Its rated at 3.1 amps draw at 240 V, so I figured it would just draw over a little double that at 120, and produce the same amount of heat, right? Could there be any way that I'm only getting half my watts? . . .
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Did you have two heating elements in series that you wired in parallel? If not, you would be getting about 1/4th the heat:
P = (V*V) / R
240 V / 3.1 A ~= 80 ohms
(120 * 120) / 80 ~= 180 W.
(240 * 240) / 80 ~= 720 W.
180 / 720 ~= 25%
As a suggestion, you might want to plot the temperature change over time. We found that after 1 hour, nearly 80-90% of all temperature rise has occurred. We're using an ~400 W block heater.
In my case, I plug in the heater before I get ready for work. By the time I get in the car 30-40 minutes later, it is as ready as it needs to be. The maximum temperature rise over a 4 hour interval is running about 35 C above ambient but one hour provides about +25 C increase.
It also helps to plot the temperature rise after starting the car. My experience is a block heater saves about 1 minute of engine warm-up out of 5-6 minutes in the moderate temperatures of North Alabama.
Bob Wilson