SailNet Community banner

1 - 13 of 13 Posts

·
Registered
Joined
·
48 Posts
Discussion Starter #1
I am confused about the energy consumption difference between a 12 volt television and a 110 volt television that runs through the inverter.

For example, I have spent this whole time thinking I needed to buy a 12 volt tv, but after thinking about it for a bit, why can't I just buy a regular 110 volt tv, plug it in, and let it run through the inverter off the batteries? What would be the difference? and how does the energy consumption differ between these two different ways to run an appliance?

(both units are going to be a 28" LED HDTV with built in DVD player. I have an 800 amp hour battery bank and a Xantrex 2500 watt inverter.)

thanks for any and all help,

Kevin
 

·
Registered
Joined
·
23,491 Posts
The simple explanation, which is about the sum of my understanding of it, is that the invertor uses power to do the inverting. They are not 100% efficient, as no machine is.

That said, with 800ah, you don't seem to need to worry about it much. Even 110v TVs these days use very little power.

I'm actually going through this for different reasons. I would like a new TV and have tried to buy a 12v set, because I just didn't want the kids to have to turn the invertor on and off. However, the picture was terrible and I returned it. Most 110v TVs used to come with those big transformer boxes, like your laptop, which converted 110v AC to some DC voltage, often 19V. You were able to chop off the transformer and splice in a DC to DC convertor to get your house 12v up to its input. However, it seems the convertors are now all internal, so inverting off the house 12v bank, back to the 110v wall, which then goes into the TV and gets converted back to DC, is remarkable inefficient. Not sure I see a good way around it anymore.
 

·
Mermaid Hunter
Joined
·
5,689 Posts
I am confused about the energy consumption difference between a 12 volt television and a 110 volt television that runs through the inverter.
Inverters will consume somewhere between 5% and 20% of the power going to the load in conversion. The lower the load as a proportion of the inverter rating the lower the efficiency.

As noted, modern TVs draw much less power than their predecessors. Check the TV itself but you can expect 35-40 W. Turning the volume down, reducing the brightness, and avoiding the DVD player will make a significant difference in power consumption.

Assume real world load is 25 W and your Xantrex has an idle current of 3A and efficiency of about 80%. 12 VDC load is 25 W / 12.6 V / 0.80 + 3 A = 5.5 A.

Alternatively you could get a small inverter like Amazon.com : BESTEK Dual 110V AC outlets and Dual USB 3.1A 300w power inverter car dc 12v to 110v ac inverter dc adapter laptop charger notebook adapter dc charger ac adapter usb charger MRI3011BU : Vehicle Power Inverters : Car El[email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@51EstY2IjKL. 12 VDC load is 25 W / 12.6 V / 0.92 + 0.5 A = 2.7 A

Efficiency and idle current make a big difference.

Some other thoughts:

Soccer mom's in mini vans and SUVs have driven a large market in 12 VDC televisions and monitors although probably not as large as you are interested in. Check outlets for custom vans. The big RVs generally use standard TVs. Still might be worth some checking around. I suspect that some of the larger models simply have built-in inverters so they won't save you anything.

You can save electrical power and storage space by ripping your DVD collection to a media system or an iPod. Their power consumption is trivial compared to a DVD player. I used to rotate my movie collection on and off the boat. Now I have all of them aboard AND I have my video locker back for other things.
 

·
Registered
Joined
·
23,491 Posts
?.... they make nice 12 volt tvs as well
I would love to find an example, seriously. I've returned two that were horrible pictures and I don't really care about the tv. As MS points out, they also need to accept varying voltages around 12v, since house batts are almost never exactly 12v.
 

·
Registered
Joined
·
133 Posts
We have a TV by Jensen that I am happy with. They make all kinds of 12 volt entertainment stuff for RV and Marine


Sent from my iPad using Tapatalk
 

·
Registered
Joined
·
1,555 Posts
We recently swapped out our 110v Phillips for a 12v Supersonic 24". It has a great picture but the sound is horrible. We use a BT speaker that also has an aux input from the TV. Much better sound from that. The Supersonic will run 110 or 12. The energy usage when running 12v is very low.
 

·
Registered
Joined
·
23,491 Posts
The exact TV that I returned was the 24" supersonic. Did not like the picture quality at all. Possible I got a lemon.
 

·
Registered
Joined
·
4,677 Posts
I like the concept of a smart tv. Blue tooth from other sources and good tv signal from air. I'm happy with my LG and it can talk to wireless portable speakers Never worried about lack of inverter 110 .I suppose if it were a problem you could dig out the Kobo.
 

·
Registered
Joined
·
1,517 Posts
I get the concept of using a dc-dc converter to change the 12v to match the voltage required by the tv...but how does one make sure that the power is nice an clean? From what I understand, tvs don like the noisy power made by converters and inverters too.
 

·
Registered
Joined
·
4,677 Posts
I suspect that the tv's internal step down power supply is buffered enough to take care of a modified square wave inverter's indiscretions. I run everything thru a good quality surge bar anyway because it automaticaly turns to shore source when dockside.
 
1 - 13 of 13 Posts
Top