Forum Discussion
25 Replies
- AnEv942NomadWhile I agree power consumption needs to be minimized if camping off-grid, not sure I agree with statement "the only thing to consider".
Mostly because topic related to low DC loads?
But to the OPs original question, my recommendation would also be an 110v TV with external inline converter. Whether run thru inverter or direct, mostly due to the selection/price etc, just a lot more options. IF you pick a small inverter for the TV look at its self use idle and efficiency numbers. A heat or load actuated fan would be nice-ours ran full bore.
I know many run the 120v TVs direct to 12v by eliminating the small inline converter (brick). Though Ive have never read where anyone had an issue doing it I was never able to cut off due to the varying voltage in camper. Just my luck. I thought I would on our new TV but wooused out.
As the inverter is needed to drive soundbar (15v) and the satellite box (120V) when its set up all I would save is the small overhead of TV. Though every lil bit helps- but my simplistic math shows using the inverter for TV and one other item (soundbar 15v, sat box 120v, or OTA ant direct 12v) costs me about the amps used to drive 1/2 of an 1141 incandescent light bulb. Switching one light to LED would offset.
----for my own entertainment, this a bit long winded
Because I was curious and didnt know and haven't seen any actual numbers I looked around to see how I could guesstimate actual usage with inverter.
Most new TVs (DC) draw less than 50 watts.
Our 21" with dvd player draws 36 watts (3 amps)output.
Our Soundbar rated at 3.67 amp output. Both use switching power supply converters verses 'wart' transformer which are also more efficient.
Our 400 watt inverter is rated at 0.3 DC amps (3.75 watts) idle, 90% efficiency (loss of inverting).
Using more common 85% efficiency and 12.0 volts converting watts to amps & back.
(consumption: Power (inverter idle watts) + load (watts divided by efficiency of inverter) = usage
(amps to watts: Amps x Volts = Watts)
(watts to amps: Watts ÷ Volts = Amps)
So Ours
3.6 watts (inverter power) + 42.36 watts (TV load 36 watts ÷ 0.85) = 45.95 watts
So thats 9.95 watts (0.83 amps) over actual demand using inverter.
The soundbar when used is higher at 50.5 watts (3.37DC amp) but its also 15v.
3.6 watts (inverter power) + 59.47 watts (SB load 50.5 watts ÷ 0.85) = 63.07 watts
Both:
3.6 watts (inverter power) + 101.82 watts (TV&SB load 36&50.5 watts ÷ 0.85) = 105.45 watts or 8.8 amps total draw. Thats 18.87w (1.6amps)over to use inverter to watch TV with soundbar. My actual numbers are a little better using 90% efficiency and nominal 12.5v plus when sound bar used TVs speakers are turned off.
Bottom line though when power is issue TV just doesnt get turned on-
To check ran battery to inverter lead thru amp meter, though I saw 1.3 amps verse the rated 0.3amp of inverter I assume led on remote switch/ standby draw of TV, SB & Sat box. However turning on tv and soundbar, Sat. box in standby, highest was 2.76 amps feeding the inverter? Nothing near the calc'd 8.8 amps. I know since replacing all the old equipment use dropped at least a 2/3 just judging by battery state but the max calc'd numbers surprised me, I expected more, the amp meter more so.
To the point pretty sure Im going to add an amp & volt meter panel to our lil inverter to see its performance.
Didnt test with the sat box on, though it was in standby, as its 14 watt AC direct, bout 0.12 amps AC. (In standby its rated at 11w).
Kinda off topic; probably should have put in separate thread, but this peeked my curiosity and I found interesting . Mostly all I did was confirm not much point in our case to amputate the converter -and actual power use thru inverter lower than I thought. Though the DC to AC and back again does seem illogical, not near 'cost' of what I assumed. Our old AC/DC TV when you turned it on the inverter fan bogged down- The new TVs power use is amazing-if they keep it up pretty soon they will be charging your batteries. - tbltonyExplorerthe only thing to consider in this debait is when you use an inverter to give 110 volts AC it takes over 10 DC amps for each 1 110 volt amp.not the best exchange.also most solid state electronics operate at 12>18 volts DC .jmho tony
- bobndotExplorer III
mkirsch wrote:
bobndot wrote:
I have a 150w PSW that plugs into an OEM 12 v outlet (not hard-wired) .
When I plug my 110 tv into it , everything is fine until I run the water pump or furnace . The PSW inverter will let out a very loud squeal. I think it is a low voltage alarm. It does this on my house battery system (2-12v. grp 31's) which reads full...12.7v.
That's exactly what it is.
When the pump or furnace motor kicks in it draws a lot of Amps starting up, which causes the battery voltage to drop like a stone for a mere moment.
The inverter is quick enough to detect it, but you are not. By the time you look at the meter, the motor is running and the voltage has risen back up.
ok tnx. When it first happened it was 11pm and quiet as could be . I couldn't believe how loud and high pitched it was . It almost sent me back into diapers before my time. :E - DWeikertExplorer II
darsben wrote:
tonymull wrote:
So all you really need is a 12v power cord for any appliance that has an AC to DC converter brick built into the original cord? Makes way more sense than inverting DC to AC then converting that AC back to DC and losing a little power at each step. Sounds like a no brainer.
Just look at the transformer on the cord and make sure it is putting out 12 volts. There may be the on outlier that does not put out 12 volt but puts out 18. Highly unlikely but you never know.
X2! An external power supply doesn't necessarily mean 12V
To the original question, the power lost in the inverter is minimal, but measurable so if you do a lot of off the grid camping every little bit helps. I agree with some posts referring to the quality of some of those 12v RV TVs, but if you can find a general consumer set with an external 12v brick, you have the best of both worlds. The latter is what I did with a Best Buy Insignia (pretty sure it's this model). I had a plug that matched the TV socket so I wired up the 12v plug and run it directly off the batteries and still have the brick if I ever want to run it off AC, for whatever reason. - mkirschNomad II
bobndot wrote:
I have a 150w PSW that plugs into an OEM 12 v outlet (not hard-wired) .
When I plug my 110 tv into it , everything is fine until I run the water pump or furnace . The PSW inverter will let out a very loud squeal. I think it is a low voltage alarm. It does this on my house battery system (2-12v. grp 31's) which reads full...12.7v.
That's exactly what it is.
When the pump or furnace motor kicks in it draws a lot of Amps starting up, which causes the battery voltage to drop like a stone for a mere moment.
The inverter is quick enough to detect it, but you are not. By the time you look at the meter, the motor is running and the voltage has risen back up. - msiminoffExplorer II
cubbear wrote:
should a person get a 12 V TV or use inverter and 110 V
As others have mentioned, as long as you have an appropriate inverter, either voltage TV will work.
I chose to go with a 22" Samsung LCD TV that I picked up at Costco. It comes with an external power brick and has a 14Vdc socket on the TV… it operates just fine on the ~12.6V from my TC's battery. I typically power it straight from the battery as this eliminates the need for me to run the inverter, which in turn saves me from wasting a little bit of energy due to conversion losses in the inverter & transformer (1.4A vs 3.1A)… plus it eliminates the wiring/clutter of the power brick.
Before making a decision based solely on voltage, I would suggest that you first evaluate your personal needs. Is there a particular size/brand you're interested in? Do you want one with an integrated DVD player? Where/how do you plan to mount the TV and what power sources are available at that location? Do you already own an inverter?
Cheers,
-Mark
On edit: I just re-checked the current using inverter & power brick and it is 3.8A, not the 3.1A I had originally posted.
So compared to running directly from a 12.6V source (house battery) it is an increase of 2.4 Amps (2.7 times more watts used!). So, at least in my configuration, running directly from the battery is much more economical in terms of total energy consumption. - D_E_BishopExplorer
skipro3 wrote:
My TV also runs on 110vac with a transformer or also known as the power wart. This plugs into the TV as 12vdc. So I also have a cigarette lighter adapter and run the TV on 12 volts. This is just like my laptop; I can run it on 110vac or from the power port on the car at 12volts.
I find 12 volts draws .5amps for the TV. The inverter draws .7amps just idling so why have the inverter and more current draw when the TV runs on 12 volts anyway?
X2, in my case the OEM inverter used to power the OEM 13"/CRT TV and the VHS recorder draws more power than my 24"/Insignia flat screen TV and BluRay Player. I do have to use the inverter for the HDMI splitter that I installed to play BluRays simultaneously on the front and rear TV's.
All three HDMI capable devises came with "wall bricks" and rather than cutting the cords, I made my own power cords. The wall bricks are rated as 12V/5A, DC, those work really well with LED lighting strips up to 16'.
If you have any further questions as to the suitability of using battery power vs 120 VAC, look at the powersource on most entry and mid level rigs. Most have "off brand" TVs that are built for the RV trade and 12volt only.
I bought a couple of surplus bricks from an RV surplus and salvage shop just for LED lighting projects at home.
As an after thought, I have not looked for a large screen TV with a power brick. You may find those harder to locate than the smaller sizes. I looked recently for a BluRay player at BestBuy, and found many of the players, including Sony's with bricks. I will continue to look for a splitter with a brick or using only 12 volt and change over when I do find one. - darsbenExplorer II
tonymull wrote:
So all you really need is a 12v power cord for any appliance that has an AC to DC converter brick built into the original cord? Makes way more sense than inverting DC to AC then converting that AC back to DC and losing a little power at each step. Sounds like a no brainer.
Just look at the transformer on the cord and make sure it is putting out 12 volts. There may be the on outlier that does not put out 12 volt but puts out 18. Highly unlikely but you never know. - Paradox123ExplorerI have a RCA TV that has a 120 cord and a 12V cord with a transformer. Bought it from B&H. I use 12V when camping without shore piwer.
- tonymullExplorerSo all you really need is a 12v power cord for any appliance that has an AC to DC converter brick built into the original cord? Makes way more sense than inverting DC to AC then converting that AC back to DC and losing a little power at each step. Sounds like a no brainer.
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