What is the needed wattage to power a standard 30'' LG TV while boondocking?

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Contestedmilk

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I am currently full-timing in my Jayco Jay Feather Baja Sport pulled by a '04 Suburban. I am looking to add solar panels to my room in order to watch tv when boondocking. I am not sure how much power my tv requires.  I'm also not sure if I need to purchase another deep cycle battery so hold the solar power I will be collecting. I am quite new to RV life, (2 months to be exact) and am looking for advice and wisdom.
 
Your tv runs on 120vac power, not 12v, so you need an inverter to make 120vac from 12vdc. Then you need battery(s) to store the power, since the DC power from the solar panel varies from zero to (whatever its max is). And you probably want to watch tv after dark, too.
Somewhere on the tv, and in its manual, it will state the wattage, or possibly the current (amps) @ 120v. Either one lets you calculate the power demand from battery/solar. At a rough guess, about 100 watts, which means a continuous 9 amps from whatever 12v source powers the inverter.
 
I used a Kill-a-Watt meter on my two flatscreens when I calculated my solar.

24" used 20 watts
48" used 60 watts
 
You can buy 12v televisions too, below is one but there are many.

https://www.amazon.com/SuperSonic-1080p-Widescreen-Compatible-24-Inch/dp/B0082ULKUE/ref=sr_1_1?ie=UTF8&qid=1475793170&sr=8-1&keywords=12v+tv
 
Frankedj said:
I used a Kill-a-Watt meter on my two flatscreens when I calculated my solar.

24" used 20 watts
48" used 60 watts
The amount of power the TV draws will change depending on the volume of the TV and the brightness of the screen at the time you measure it.
 
SeilerBird said:
The amount of power the TV draws will change depending on the volume of the TV and the brightness of the screen at the time you measure it.

I never use audio from a TV. It is either a sound system or sound bar for audio. I also took my measurements using the TV's as multiple computer monitors with white screens. I also tested them using fast moving graphics/video.

After taking measurements I rounded up.
 
I was just pointing out that there really isn't one figure that you can rely on as the absolute power consumed by a TV. It varies, it is not like a hair dryer that is always the same wattage.
 
The Kill-a-Watt meter was essential when I started designing my electrical a year ago. Just hooked in the final piece 2 days ago. A Magnum 2000 watt pure sine inverter.
 
Many TV's are already 12volt but come with a 110 cord only.

Amazon sells 12volt cords that work with these TV's.

My 16 inch is 12 volt but came with 110 cord. We have used it with a tiny 200 watt inverter. A 12 volt cord would make more sense since my RV came with 3 cigarette lighter outlets.

I used a computer display table mount attached to the corner of my booth table for mine. It goes up and down and rotates, so the TV can be aimed 360 degrees, super handy to watch it from anywhere in the forward section of the coach.

Where there is a will, there is a way.

Yeah, people laugh at my "tiny" 16 inch TV, but the color is vibrant and clear. It can be aimed at kitchen or club chairs or either side of the booth or in the middle for both booth sides to watch.

Alternatively I have a cord run from it to the stereo speakers, so if a really good movie is on, I can get great sound. Also have same cord running to the comfy chair with headset so when my friend visits and wants to watch shoot-em-up testosterone movies, I can listen to my music and he can wear TV headset. We both like this arrangement when need be.I think he likes it cause he can tune me out.  ::)

Alternatively get a tiny power inverter to run the TV only. They are fairly cheap from $20 or so.
 
Lots of speculation and opinions, except for FrankedJ who actually measured a 24" & 48" flatscreen.

Being curious I went out to my RV to measure the actual 12V current being used by my Samsung 32" flat screen LED TV. This 12V DC current is coming through the inverter and changed to 120V to the TV.  NOTE: This is an LED TV.  If you have a plasma TV or a non-LED flat screen they pull more power.

NOTE: My Trimetric battery monitor and the Battery monitor for my lithium batteries don't display any changes less than 0.1amp (one tenth of one amp). 

--  0.0amps or less than 0.1amp between the TV being unplugged and then plugged in but turned off.  (In other words "no change on the meter)
--  3.0 amps (36watts) when the TV is turned on. This matches pretty closely what FrankedJ saw for the 24" & 48"
--  0.0amps or less than 0.1amp between the brightness being as dim a possible and being as bright as possible.  (In other words "no change on the meter)
--  0.0amps or less than 0.1amp between the volume being as low a possible and being as loud as possible.  (In other words "no change on the meter)

Now I'm sure there is "some" power usage difference with the volume or brightness being as much as possible or as little as possible.  However since that is well less than 0.1amp I would consider it not worth considering.

Someone suggested looking at the label on the back of the TV.  Good suggestion.  My TV shows 59watts, but also lists 33watts as typical usage.  That 33 watts matches what my test shows. 


So much for the TV.

Time to talk about inverters. 
--  Just turning on an inverter will take some 12V power being on.  How much depends on the inverter.
--  My Magnum 2000 watt inverter uses about 2 amps when it is turned on
--  A 100 watt inverter used to only power the TV (which only takes 36watts) probably uses a 1/4 amp or less when being on. 

What size inverter you use to power the TV makes a huge difference.

IF you watch satellite TV the receiver (DVR) that pulls quite a bit of power.  My Dish Network DVR pull about 4amps of 12VDC though the inverter.

So if you have a 2000 watt inverter, 32-48" TV and a DVR you are looking at:
--  2 amps  Inverter
--  3 amps  TV
--  4 amps  DVR
--  9amps  total 

That is quite a bit of amp hours (36AH) for 4 hours of TV, plus lights and what not.


 
    Contestedmilk,  If your unit is anything like ours....when we turn on the inverter, it powers the entire intertainment system and uses far more wattage than a stand alone tv. If that is the case... you may consider a small (say 800 watt) inverter to power the tv ?only?! We have that set-up, to power our small chest freezer (we boondock for somewhat extended periods) and the small bedroom tv. Though where we camp...we have no tv reception from the standard roof-top antenna.  :(
 
When I replaced my TV's I noticed that the cheapo Best Buy 32" LED that I bought uses a power brick cord, just like a laptop.  I checked the power output of the brick and noticed that it was 12v.  I inquired at Best Buy about eliminating the brick and just wiring the TV straight to the coach's 12v system.  Of course, nobody at the store level could confirm or deny the advisability of such a thing.
Anyone got a clue as to if this would work?  Sure be nice not to have to sweat an inverter for just the TV.
 
Old_Crow said:
When I replaced my TV's I noticed that the cheapo Best Buy 32" LED that I bought uses a power brick cord, just like a laptop.  I checked the power output of the brick and noticed that it was 12v.  I inquired at Best Buy about eliminating the brick and just wiring the TV straight to the coach's 12v system.  Of course, nobody at the store level could confirm or deny the advisability of such a thing.
Anyone got a clue as to if this would work?  Sure be nice not to have to sweat an inverter for just the TV.

Of course it will work, many have done just that.  Did the salesman ask if you want fries with that?
 
My guess is that since it's not mentioned in the literature that came with the TV, the BB employees didn't want to set themselves up for a lawsuit or something.  ::)  It really did sound like the guys I talked to were testifying before Congress or something.

I, myself, wouldn't sue in a case like that, but then I'm pretty easy-going, and willing to accept the consequences of my own actions.
 
My 32" Samsung has a 120 to 19 volt brick, and my 22" Naxa has a 120 to 12 volt brick and a 12 volt car cord. When I bought the Naxa for the bedroom I thought I had a 12 volt source in the closet, but do not. My coach has a 400 watt inverter that powers the TV and the VCR, CD player Rec. Don't know how long it will run them, because I've never used it boondocking.  I had a 22" Naxa in my Challenger that did run off of the 12 volt plug in the bedroom, but was concerned about the difference in voltage when plugged in, because it was over 13 volts but it never bothered it. I was worried that if the company that built the TV didn't offer a car cord, just maybe it wasn't able to run on a varied voltage. I know when I first start my coach it runs over 14.6 volts for a bit. My PD9260 also runs over 14.4 volts, sometimes. How much extra voltage can these 12 volt TVs take? 
 
Well, 12vdc is 12vdc, so it ought to work. Neither a store employee or the tv manufacturer is going to promise that, though. You are "on your own".

It's true that a vehicle or RV system doesn't really run at 12v - they generally operate in the 13-15v range. In fact, even a fully charged 12v battery is 12.6v. The "brick" is probably regulated to a narrower range, but whether the tv can handle much variance is anybody's guess. The better quality brands probably have more/batter power management circuitry, but that is often one of the areas that gets skimpy when they start cost-reducing.
 
While a DC-DC converter may be an option, one must remember they are only about 80% efficient and will dissipate the other 20% as heat.  You would take about the same performance hit using an inverter, then the power brick that came with the TV
 

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