Real-world Watts/Amps readings from my RV (Xbox, TV, computer, chargers, more)

[concretebox]

So I spent a couple hours today measuring the watts and amps of every 120-volt electrical device in my CamperVan. I thought the results might be interesting to you all.

Highlights:
<bl><li>With the converter on, and the only 12-volt device "powered on" being the propane detector, the rig consumes 68.3 watts and 1.67 amps when connected to shore power. With the converter off it draws 2.6 watts and 0.03 amps from shore power.</li>
<li>The Xbox360 uses slightly less power playing a game off the hard drive than the disc. This should be obvious, as running the disc drive would require more energy than just reading the hard drive.
</li><li>The TV consumes less power displaying SD video than it does HD video, and even less power displaying video with Mono sound.
</li><li>The quality and source of the video being streamed via the XBOX (YouTube, Netflix, Amazon) seems to have no effect on the power consumption of the TV. Although all streaming services drew slightly different power amounts from the Xbox.</li>
<li>Curiously, the TV consumes slightly less power playing HD video from a USB drive than it does broadcast HD. (Perhaps the built-in ATSC tuner is turned on only when needed?) Does anyone have an external ATSC tuner they use with a computer monitor? How much does it consume?</li>
<li>My little "600 watt" microwave consumed a whopping 1125 watts at peak (connected to shore power).</li>
</bl>


Electrical usage notes:
<bl><li>Shore Power cord-converter turned on: 68.3 watts, 1.67 amp.
</li><li>Shore Power cord-converter turned off: 2.6 watts, 0.03 amp.
</li><li>Xbox Video-Main menu idle: 58.4 watts, 0.79 amps. Streaming Amazon: 58.4 watts, 0.79 amps. Streaming Netflix: 60.5 watts, 0.82 amp. Streaming YouTube: 61.2 watts, 0.82 amp. Streaming Internet Explorer video: 65 watts, 0.88amp.
</li><li>Xbox Gaming-Paying Saint's Row 2 on disc: 80 watts. Playing Bioshock Infinite on disc: 82 watts, 1.06 amps. Playing Skyrim off Hard Drive: 76 watts, 0.99 amp. Playing Lara Croft and the Guardian of Light off HD: 72 watts max, 0.9 amp
</li><li>TV Broadcast/USB-Watching broadcast 1080i: 16.2 watts, 0.21 amp. Watching 480i: 15.6 watts, 0.21 amp. Very low quality picture (no data), mono sound: 13 watts, 0.18 amp. Watching HD video from USB thumb drive: 15.2 watts, 0.2 amp.
</li><li>TV Streaming-Xbox menu idle: 18.4 watts, 0.24 amp. Watching Amazon (1280x720/60p, 16x9): 18.4 watts, 0.24 amp. Watching Netflix (1280x720/60p, 16x9): 18.3 watts, 0.24 amp. All TV readings taken on "Dynamic" picture settings (brightness and backlight at maximum).
</li><li>WaterPik: 11 watts, 0.17 amp.
</li><li>Personal Blender (blending jar empty): 130 watts, 1 amp.
</li><li>Microwave-idle: 1.3 watts, 0.02 amp. Heating ceramic coffee mug half full with ice water: 1125 watts, 9.91 amp.
</li><li>E-cig charger: 1.9 watts idle, 2.1 in use, 0.03 amp on both.
</li><li>Phone charger: 6.3 watts, 0.08 amp.
</li><li>Heating pad-Medium: 49.5 watts, 0.4 amp. Low: 48.1 watts, 0.39 amp.
</li><li>Electric blanket-High: 140 watts, 1.12 amp. Medium-134 watts, 1.09 amp. Low-0.0 watts, 0.0 amp.
</li><li>Rope light with dimmer switch-High: 17.1 watts, 0.14 amp. Fifty-percent dim-6.6 watts, 0.09 amp. Minimum dim: 3.5 watts, 0.07 amp.
</li><li>Laptop charger-Lid closed, 1 watt, 0.02 amp. Playing Full screen HD video- 70 watts, 0.58 amp.</li></bl>

 

[akrvbob]

I'm assuming you are interested in how much power will be drawn off the battery by these devices. If so, you've made a common mistake.

To know how many amps will be drawn from the battery you divide by 12 volt, not by 110. So if your 110 volt device is 120 watts, divided by 12 then it draws 10 amps from the battery. But of course the inverter is wasting more power, so figure at least 11 amps and probably 12 or more.

I can tell you that you can't possibly run all that from 100 watts of solar without shore power. 500 watts should do it okay.
Bob

 

[concretebox]

Thanks Bob. I knew there had to be something I was missing.

If my tv and Xbox combined used 79 watts while streaming video, then it uses 6.53 amps. Adding about 20 percent for the inverter, that's about 8 amps from the battery per hour?

If I had no other power drain, then I could watch streaming for about 6.25 hours before discharging a 100Ah battery by 50 percent?

 

[Seraphim]

Thanks Bob. I knew there had to be something I was missing.

If my tv and Xbox combined used 79 watts while streaming video, then it uses 6.53 amps. Adding about 20 percent for the inverter, that's about 8 amps from the battery per hour?

If I had no other power drain, then I could watch streaming for about 6.25 hours before discharging a 100Ah battery by 50 percent?

Yes.

Sorry - not Bob lol

---

Using 110 via an inverter, just divide the wattage by 10 to get the amp drain on your 12v battery. It's easier.

 

[akrvbob]

Possibly, but unlikely for two reasons:

1) Remember, that is the manufacturers rating and I doubt that battery every had a full 100 ah in it and no matter how well you treat it it is slowly degrading.
2) It's unlikely you got it 100% charged the day before.

And if you do, what will you do if it's cloudy the next day?

Operating your solar power system right to the edge of it's capacity is never a good idea, especially with a small system. First you meet the essentials, then you add luxuries.
Bob