How much power does the Television take at 12 volts?
I like to measure things, and have the equipment to do it in many cases. It has often been asked here how much power do things take from their battery. Here is some measurements I just did. I won’t bore you with the meters and stuff.
The Television is a Samsung 21” which came in my 2014 FC 20’. The DVD player is also a Samsung supplied with the trailer. The radio/sound system is the diabolical Sony which also was original.
The TV operates on 120 volts via a power supply velcro’ed to the rear of the set, which then supplies 14 volts DC to the TV via a special plug that is unique to the set. Thus, even if it would operate on 12 volts DC, I was not willing to modify the system to test it out.
The TV, on 120 volts grid power takes 20 watts with a stationary display test system I used. If that 20 watts came from 12.5 volts directly it would be 20/12.5 = 1.6 amps. (no inverter losses).
Since all inverters to produce 120 volts from 12.5 volts (realistic battery actual voltage) have conversion losses, I measured 3 different inverters and how many amps they took to run the TV.
The first inverter is a “modified sine wave” inexpensive Xantrex 400 watt unit. Cost was about $25 when I bought it.
The second is a Morningstar “true sine” 300 watt inverter costing about $225. It is the best small sine wave inverter I have found as it takes a minimal amount of stand by power, and also has a search function, which shuts it down until a 120 volt load is applied, then it automatically starts up.
The third inverter is the 1000 watt WFCO sine wave inverter which was an option I selected for my trailer when I ordered it. It works well, but has a very high stand by loss when running but no load is applied. Most all true sine wave inverters I have seen have similar high stand by losses, the Morningstar being the exception.
Results:
The Xantrex and the Morningstar inverters both required 2.1 amps to run the television. That means they were using 2.1 x 12.5 = 26 watts. (Watts = Amps x Volts).
So, there was a 6 watt penalty over line power of 20 watts for converting from 12 to 120 volts to supply the inverter losses. In amps, that is 0.5 amps extra.
The WFCO is a different story. To run the TV it took 3.73 amps or 3.7 x 12.5 = 46 watts. Over double the actual amount the TV requires on line power. In amps that is 1.6 amps more than the other inverters I measured.
The Samsung DVD player takes 4 watts on line power.
I put a DVD in and played a movie with very low TV speaker sound only.
Xantrex and Morningstar took 2.55 Amps or 32 watts for either one. So, the DVD added 6 watts via the inverter.
The WFCO took 3.85 Amps or 48 watts.
Then I turned on the
12 volt Sony radio sound system with the sub woofer, and figured out how to connect it to the TV (more head scratching, it is why I call it diabolical).
The Sony at 12 volts, the TV and the DVR together on the inverter, playing at moderate volume and powered by the Morningstar or Xantrex took 4 to 5 amps total. That depended on the volume and background music on “The Rose” video I had running. That is 50 to 67 watts drawn from the batteries. The WFCO would have increased that to 65 to 82 watts, or 5.3 to 6.5 amps.
Bottom line:
The TV operating on a cheep modified sine wave inverter, at low volume using the TV speakers does not take too much power. The Morningstar is very similar.
The same TV on the WFCO inverter takes a lot more for the inverter losses.
The TV plus DVD player and Sony Radio sound system can almost double the power with the modified sine wave or Morningstar inverter, and triple the power with the WFCO inverter.
Now you know more than you really care to know. LOL.
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