low power 12vdc lcd monitor

[cizzi]

I'm looking for a low power 12vdc lcd monitor (size not important but at least 14-15 inches). Google doesn't turn much of these, the ones I did find were 4000$ range made for marine applications. I'd like to pay under 400$ for a 15inch size monitor. What are the factors in this type of product? Is it the color that takes alot of watts? Or is it the fact that its LCD vs CRT (or does crt use even more?)).

When I plug a standard AC 120V monitor in my wall, I'm assuming it has a rectifier that converts the AC to DC for the electronics inside the LCD monitor, so why can't I find something in native 12VDC? Laptops must do it all the time but I'd like something for a desk. Thanks for any information.

[LBergman]

Just a quick point, but I don't think 12VDC is the native voltage for LCD monitors. The electronics likely use 1.8-5VDC with the back light probably requiring some different voltage, so DC-DC conversion would still be needed inside the unit. Even in a laptop, the battery voltage has to be converted to several different voltage levels.

[cizzi]

Just a quick point, but I don't think 12VDC is the native voltage for LCD monitors. The electronics likely use 1.8-5VDC with the back light probably requiring some different voltage, so DC-DC conversion would still be needed inside the unit. Even in a laptop, the battery voltage has to be converted to several different voltage levels.

Thanks for pointing that out, so we could use a voltage regulator like a 7805 for example to convert from 12 to 5 volts dissipating the extra voltage tru the heatsink. However my goal is to find a monitor that uses 10 watts or less, is that even possible or realistic ?

[LBergman]

Thanks for pointing that out, so we could use a voltage regulator like a 7805 for example to convert from 12 to 5 volts dissipating the extra voltage tru the heatsink. However my goal is to find a monitor that uses 10 watts or less, is that even possible or realistic ?

Without a backlight, I think it's quite possible. The backlight could be the thing that breaks the "current" budget...maybe. I know with my LCD television, the 12VDC draw through my inverter varies from 9 to 18 amps by just adjusting the backlight level. My laptop does the same thing, but to a much lessor degree with its far smaller screen (a ~1amp difference over it's brightness range).

[Brock]

I haven’t seen then in 15 inch sizes but I haven't looked either. I would look at portable DVD players with screens built in or add on second screens. Also take a look at automotive / mini-van stuff. I have seen lots of screens for kids to watch TV from a single DVD player. Both of those should be made to run from 12v.

[jacobs]

I remember seeing a 15" lcd monitor powered by a 12vdc wall wort several years ago. It wasn't anything special like marine. It probably was at Costco or Sam's Club but I'm not sure. I'd watch eBay or check at computer stores and ask if they use a wall wart and if so what voltage the wall wart is.

[BB.]

Just remember "wall wart" type 12 volt systems is that they many times do not like the ~10.5-15.5 volt range of a solar PV system (they may work better with a car where the voltage is around 13.6-14.2 volts).

And, 7805, plus other "analog" regulators are not energy efficient... They "burn off" the excess voltage as heat--so they do not save any energy. For example, converting from 14.2 volts (charged battery) to 5 volts (with a 5 watt load) would require the regulator to dissipate:

(14.2v-5v)
----------- * 5 Watts = 9.2 Watts of "lost" power
5 volts

Switch mode power supplies (buck, boost, etc.) are much more efficient when converting voltages (and currents) from one level to another. But can be more expensive and difficult to implement--the above example would have wasted less than ~0.5 Watts of power as a properly designed and sized switch mode power supply (as with anything electronic--it all depends on the application, needs, and volume).

-Bill

[mike95490]

Most smallish LCD monitors have wall wart or Brick on a String type powersupplies. I'll look up mine when I get home.

Most likely, you will be better off using a small pure sine inverter to power the finicky electronics. The power distribution of 120VAC can't be beat, so if your monitor is pulling

I know with my LCD television, the 12VDC draw through my inverter varies from 9 to 18 amps by just adjusting the backlight level.

18 amps, that's going to be a hefty 12V cord for it.

[n3qik]

Got a 15" Planar LCD that has an 12V 4 amp wall wart. Mod # PL 1500M.

Here is one on fleabay:
http://cgi.ebay.com/Planar-15-LCD-Mo...QQcmdZViewItem

[cizzi]

4 Amps at 12vdc? if P=E x I that would mean it generates 12 x 4 = 48 watts?? I'm sure i'm wrong on that.. help me out here..