Have 120v home TVs eclipsed the efficiency of 12v RV TVs?

Endurance
Endurance Solar Expert Posts: 40 ✭
in Off Grid Solar & Battery Systems #1
I am shopping for a 32" TV for my houseboat. Common logic has been that 12v RV units are more energy efficient than household TVs. I found a Jensen 32" RV TV. In its owner's manual (buried on page 30) it says that it consumes 90 watts. link here: http://www.jensenmarinedirect.com/jensen-32-led-dc-tv.html

I also shopped for a household TV with the same screen size. The top-rated 32" TV according to consumer reports says on its spec sheet that its maximum power draw is 59 watts and that its typical draw is 33 watts. link here: http://www.samsung.com/us/video/tvs/UN32EH5000FXZA-specs

Even if I allow 15% additional power because I have to invert 120v power from my 12v system, it looks like the household TV is the clear choice for energy efficiency. Could it be that modern household TVs have gotten so much better than what we used to think of as energy-efficient RV TVs?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Have 120v home TVs eclipsed the efficiency of 12v RV TVs?

    If you were talking strictly powering the TV, an inverter drawing 6 Watts would do that. So the home TV comes to 59 Watts + 6 Watts = 65 Watts. Well below the 90 Watts of the RV TV. Even a big inverter drawing 20 Watts would bring the total to 79 Watts.

    But can you trust the Watt rating on any of these? It would be interesting to measure the actual power usage compared to the rating on the DC unit and see how close it is.

    Theoretically it would be possible to 'hack' some home TV's and drive them direct from DC too.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: Have 120v home TVs eclipsed the efficiency of 12v RV TVs?

    In general, yes, 120 VAC appliances are becoming as efficient as 12 VDC devices, and sometimes even more so (there are the newer EnergyStar requirements, much larger market for homes vs RV/portable). The RV/DC market can end up lagging the newer mass market appliances.

    The other issue is that many 12 VDC appliances (such as a TV with a 12 volt converter in the line cord), can run from 12 volts--But can it run from 10.5 to 15.5+ volts that can be seen on a normally operating deep cycle battery bank...

    So--I tend to recommend going 120 VAC because you now leave the DC power issues with just the AC Inverter--Much fewer worries that equalizing your battery bank with the TV running is going to wipe out its DC input... And the 120 VAC wiring is 1/10 the amount of copper to send power anywhere.

    It still is nice if you can connect a kill-a-watt type meter on your 120 VAC appliances to confirm that they are somewhat close to their energy ratings (many TVs are set to "demo mode" in the store and can use more electricity,back lighting, than would would normally use in your home).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • YehoshuaAgapao
    YehoshuaAgapao Solar Expert Posts: 280 ✭✭
    #4
    Re: Have 120v home TVs eclipsed the efficiency of 12v RV TVs?
    Cariboocoot wrote: »
    If you were talking strictly powering the TV, an inverter drawing 6 Watts would do that. So the home TV comes to 59 Watts + 6 Watts = 65 Watts. Well below the 90 Watts of the RV TV. Even a big inverter drawing 20 Watts would bring the total to 79 Watts.

    But can you trust the Watt rating on any of these? It would be interesting to measure the actual power usage compared to the rating on the DC unit and see how close it is.

    Theoretically it would be possible to 'hack' some home TV's and drive them direct from DC too.


    My LED TVs are using less than 'stickered' watts. The backlighting is a modern LCD/flatscreen TV's largest power consumer (especially non-LED). The configurable brightness of the backlight on LED TVs plays a huge role in power consumption. If you watch TV (or use TV as a monitor) in poor lighting, a brighter TV will just give you headaches anyway. My Sharp 30" 1080p LED TV is running 50 watts, advertised at 75 watts. My Samsugn 22" 1080p LED TVs run around 30 watts.
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #5
    Re: Have 120v home TVs eclipsed the efficiency of 12v RV TVs?

    When using an inverter in this type of application, you'll want one that doesn't throw noise all over the spectrum, and interfere with the reception itself. You may need to locate the antenna far away from the inverter, which in an RV situation may be impractical.
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