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Compass Marine How To | all galleries >> Compass Marine How To Articles >> Inverter Inefficiency > TV Running On A 400 Watt Inverter
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TV Running On A 400 Watt Inverter

TV Running On A 400 Watt Inverter

So maybe it's not that much more efficient but 6 tenths of an amp is nothing to snub your nose at. The 400 watt inverter ran the TV using only 5.2 amps or 5.2 ampere hours for every 60 minutes of run time. It was a mere 25% inefficient when compared to direct DC. Again this is a far cry from the 10% claimed by most manufacturers, and often incorrectly believed by boaters.

This certainly was not a very scientific experiment but rather a real world experiment designed to show what one item, a TV, designed to run on both 120 volts AC and 12 volts DC, will do run both ways.

It is quite clear that if you have the option to buy a device that will run on 12 volts DC vs. 120 volts AC, you should buy it. Inverting power from 12 volts DC to 120 volts AC, then back to DC again is a terribly inefficient way to power devices off your boats house bank of batteries..

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Martin 26-Nov-2008 00:03
Great Test!
I was trying to get answers for the same thing you showed here.
I was thinking of putting Christmas lights for next year on my CS27 running the new LED lights. I was also trying to figure out whether to use a generator for them or an inverter.
I think a small generator would be best.

Stenn 25-Oct-2008 22:31
There's one aspect you are forgetting in this discussion of power-conversion inefficiency....the load-device's power supply. That 5-something amps of power consumption is not all the inverter's fault, you have to remember that you're also running through your TV's AC-to-DC power supply, which is then down-converting from 110/120 volts to it's internal voltage, which may actually be 5 volts, not the seeming 12 volts you also have the option of feeding remember that the device's internal power supply is also wasting power. This is not to detract from your point that you should be using the DC input of any device that gives you that option, that's a "given."

Another point to consider is that the common, affordable inverter is only putting out a simulated, "modified" sine-wave at 60hz...sort of a smoothed square wave, and some devices are VERY inefficient and run very poorly (such as microwave ovens) when fed a "modified sine wave." For these picky devices, you would have to buy the very expensive "pure sine wave" inverter.