12 volt or 110?

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
Kevin Means

Kevin Means

Site Team
Joined
Aug 3, 2010
Posts
5,120
Location
Hereford, Arizona
A friend of mine just bought a new LCD flat-sceen TV, which will run on 12-volts via a cigarette lighter, or when plugged into 110 (He has an inverter in his Class C).

He wants to know if it makes more sense (less power consumption) to use it on 12-volts through the cigarette lighter, or should he just plug it into 110 and run off the inverter. Or does it really make any difference? I told him I didn't know but I'd check with the experts (you guys). I also suggested that he read the owner's manual, but hey... he's a guy.

What do you think?

Kev
 
He might want to check which battery the cig lighter is powered from. If the chassis battery, it would make more sense to power from his main inverter, so he doesn't unknowingly run his chassis (starting) battery down. If he chooses to use the cig lighter, the 12V wire should be kept as short as possible and, if necessary, use a 110V extension to the TV.
 
Ahhhhh...

Good point about which 12-volt source he's using. I got the impression it was on the coach side but I'll check. Thanks Tom.

Kev
 
The tv itself uses the same amount of power either way.  I'm assuming he runs on shore power when available? And this question concerns boondocking, when the choice is limited to inverter or 12v from battery?  If so, it is slightly more efficient to run from 12v, because that's what the tv runs on internally anyway (actually, 12v & 5v). When you plug the tv to120vac, it changes it back to DC anyway. Plus, an inverter wastes some energy converting 12vdc to 120vac (it's about 90-95% efficient), and then the tv changes it right back anyway.

So, the battery source concern mentioned above is the only real concern.
 
As stated the statement "The TV itself uses the same amount of power" is correct.

HOWEVER the brick that converts 120vac to 12vdc is somewhere between 40 and 90 percent efficient, Likewise the ivnerter, at best, is 90 percent, So there is somewhere between a slight and a major difference in the power drain depending on the converter (The brick) that came with the TV.

That said... I have heard stories of SOME 12 volt/120 volt models that were a bit "Finicky" on the 12 volt side, when the failed the service man said "It's because of the higher than 12 volt power in the motor home"  Frankly I suspect he was taking an easy out and not telling the truth.. But for a fact I do not know.  IF I WERE building the TV, 14, or even 20 volts would not be a problem.. But I don't design TV's.  I design power supplies on occasion, LIke one 3 amp job that can deliver 10 or more if I bypass the breakers, (And has).  Like I said, IF I Designed.. I over build.
 
Always more efficient to run directly from 12 volts if possible.  Inverters are not 100% efficient.
 
In previous motorhomes when I have had a 12V/110V TV I have always run it on 12V when supplied by the coach batteries. 
 
Gary,

Yes, it is a boondocking issue, and he plans to run the TV off the coach batteries. Your explanations all seem to have the same reasoning behind them and it makes sense. Thanks all.

Kev
 
You must log in or register to reply here.

Latest posts

Members online

Total: 988 (members: 8, guests: 980)

Forum statistics

Threads
131,981
Posts
1,388,592
Members
137,727
Latest member
Davidomero
Back
Top Bottom