Thread: LCD questions/ voltage

The reason for using a power adapter for an lcd monitor is simple: Regulation.
Not as in a requirement, but as in protection by supplying a constant voltage.
Most lcd monitors sold for automotive use can handle automotive voltage safely and there is some sort of regulating going on internally. There has to be. LCD panels in general need 3.3 or 5 volts to operate, and only need this to be a few milliamps.
But, as I am sure you have seen plastered all over here and possibly other forums the failure rate among lcd monitors in the automotive world is quite high. Why? because they are being fed Unregulated power. A car typically outputs 11.5 to 14+ volts DC at any given moment. This constant fluxuation of voltage is death for electronics. Most can handle .6-1.2 volts in either direction over a short time, but the constant up/down of the voltage roller coaster that some of these monitors sees is simply more than they can handle.
By using a Regulated power supply, you are providing a smooth, constant, true 12 volts to your equipment, and thus ensuring that you won't be sentencing your LCD monitor to an early grave.
Now you may be wondering, why don't other automotive electronics suffer a similiar fate? They don't require a regulator or power adapter right?
Well, yes...and no. Car audio, and electronic components in your car have regulation built in. This regulation is much better circuitry, and, with the exception of the audio equipment, most of the componets don't draw enough amps to be a problem, so onboard regulation does not require much in the way of circuitry, electronics, etc.
So, IMO, to be safe and to protect your investment, use a dc-dc power adapter, a voltage regulator, or a dc-dc power supply.
Depending on what all you plan to run in your car, a single source will provide enough available amps to run several components.

My LCD's input is listed at 12VDC, which I take to mean 12 Volts of Dedicated Current. Whether it can function properly under more or less, that is what I do not know. Hopefully my LCD's will come in with a manual that will better explain their capabilities. If anyone has experience with PA LCD's, their input would be greatly appreciated. I think that I am going to call up some audio/video companies and ask them about this. Thanks a bunch for the help, I appreciate it.

I just realized something... Since most LCD's are designed to run off 12VDC, and most DVD/CD players try to force you to ground off on the E-brake for the DVD's to play; perhaps all these are interconnected as a bastardized attempt by the companies to prevent any video from being played while driving (reducing liabilities, of course). Most cars jump to 13V-14V when on, and a hard-wire to a battery will sometimes cause problems with the LCD's recieving too much voltage, since most seem to have no internal voltage regulator.

Does any of this make sense? The whole thing is to prevent us from letting our friends and family watch movies/play games while driving... This will not solve my problem, as my car runs at 13V+ even when not running (chalk it up to a kick-butt alternator, lol!), so a hard-wire with these types of LCD's is forever out of the question for me. So there are no modules specifically for this problem. Well, time to enlist some nerdy friends of mine to help out with the upcoming "solder-fest.."

What would be a good power supply for powering 3 LCD's? I don't mind hardwiring a PSU to the battery, but what should be the output voltage/amps? Some of the ceaper ones are a 12V/15A; and I am not sure if that is overkill or not... Are there car-specific PSU's? On to more searching...

Cool, I found a neat little power supply from Opus Solutions, and they have a DC/DC supply that is rated at 12V/5A output; and a quick call to Opus showed to me that The 80W model would be the best option for powering three LCD monitors, and the overall cost on their site is $72.00 without a case (circuit board only). They even provide the wires and the wiring diagrams to help clarify things a bit, and the rep. on the phone was really nice in answering all of my inane questions involving switches, splicing, grounding, etc. I will certainly shop around for a better price, but this guy seems like a good option. What do you think?

Originally Posted by dreadshawn

Hopefully my LCD's will come in with a manual that will better explain their capabilities....

HA! good luck. Any useful technical information will be lost in translation.
Your best bet is to just be safe and use the dc power supply you found through opus.

Are there any HU's out there that have a good voltage regulator in them, or is this more of a "signal-only" affair with them? My HU is going to be the JVC KD-AVX1 CD/DVD player, and there seems to be so many "gee-whiz" functions on there that I am having trouble sorting them out! Is anyone familiar with this particular model? I am likely to go with the PSU for safety's sake, but curiostiy is what's got me posting the question now.

Thank's for reading, y'all.

Nice simple setup. But, at full load, how hot?