| 19" TV power draw through inverter [message #114395] |
Sun, 06 February 2011 17:58  |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
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After reading about Dan Gregg's TV and power draw, I decided to make some measurements of my own.
The TV is a two year old Vizio 19 inch flat screen, 120 volt AC input set. With a Kill O Watt meter (KOW) on line power, it takes 25 watts.
I hooked the TV up, through the KOW to a Xantrex 400 watt modified sine wave inverter I have, ran it from the battery in my car and measured the DC current draw of the inverter with a digital meter of fairly good quality.
Results:
1. Inverter on, but not hooked up to anything. DC input was 12.5 volts and .28 amps while the inverter was running. So, the watt draw of the inverter with nothing connected to it was 12.5 x .28 = 3.5 watts.
2. Inverter on, supplying power to the TV, also on. DC input was 12.1 volts and 2.86 amps. So, the watt draw of the inverter/TV combo was 12.1 x 2.86 = 34 watts. The KOW meter said the TV was taking 24 watts.
3. The inverter efficiency, at this low load of 24 watts for a 400 watt inverter, is 24/34 = .70 or it is about 70 % efficient overall. Considering the standby 3.5 watts is always there if the inverter is on, and subtracting that from the total draw of 34 watts you have a 24/30.5 = 79% efficiency. Not bad considering the inverter only cost $25. Also note that the inverter input voltage dropped .4 volts due to wiring and a very small auto battery supplying the power.
So, there are some numbers for my set and inverter.
Might give someone some ideas to think about.
No, I did not watch the Super Bowl. This was much more fun.
Rob Allen
former owner of '76 x-PB
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