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why dont people use "home" screens with inverters?

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  • why dont people use "home" screens with inverters?

    hey. in my recent install, i was trying to find a good screen for my car pc. i wanted something around 10 inches, but all i could find was lilcrap and stuf like that, wich are very expensive and WAY not , all good for what you need on the car.. (personal opinion, not applying to all screens ofc )
    at the end, i dicided that i would go for a 15 inch home screen, with an dc to ac inverter , to run it. if you need touch as well, a touch panel is easy to be found.

    so i'v been using it for the past two months, and its awsome. ultra bright, HD , bla bla.
    and i was wandering, why not many people do it that way? at best someone would go with a laptop screen, but seems way to hard... so i wanted to see if some one had a reason why not, to do it

  • #2
    Mostly because of having to use an inverter, I would suspect. SNO

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    • #3
      I use a 12 volt 15" LED I found on Amazon.

      Not for use when driving.
      link to my CTS-V project:

      http://www.mp3car.com/worklogs/153699-a-macd-v.html

      Comment


      • #4
        well yea, that was my first though as well. ( i also didint wont to.) but , with a relay to turn it on automatic, it dosent seem like a big deal (Although i do, dont know about noise issues)

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        • #5
          Check out this company:

          http://www.chasecam.com
          link to my CTS-V project:

          http://www.mp3car.com/worklogs/153699-a-macd-v.html

          Comment


          • #6
            Noise should not be an issue. Both dc-dc converters and dc-ac inverters use high-frequency switching (dc-ac or dc-ac-dc). In fact some d-dc converters are known to be far noisier than inverters.

            The main reason inverters are not used is their inefficiency - typically 20% higher than dc-dc converters.
            Plus often higher idling/stand-by currents and worse tolerance to low voltages during cranking etc).

            Many dc-dc converters also have a means for low-current idling whereas inverters don't - they are either on and idling, else off.

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            • #7
              Originally posted by settra View Post
              hey. in my recent install, i was trying to find a good screen for my car pc. i wanted something around 10 inches, but all i could find was lilcrap and stuf like that, wich are very expensive and WAY not , all good for what you need on the car.. (personal opinion, not applying to all screens ofc )
              at the end, i dicided that i would go for a 15 inch home screen, with an dc to ac inverter , to run it. if you need touch as well, a touch panel is easy to be found.

              so i'v been using it for the past two months, and its awsome. ultra bright, HD , bla bla.
              and i was wandering, why not many people do it that way? at best someone would go with a laptop screen, but seems way to hard... so i wanted to see if some one had a reason why not, to do it
              Two reasons:
              1. To avoid using an inverter. They are bulky & inefficient. Low-quality inverters are also more likely to introduce EMI interference (aka "noise") into your audio system.
              2. Most home/office monitors aren't as bright. They don't have to be, as they have to be read indoors, not in direct sunlight.
              Have you looked in the FAQ yet?
              How about the Wiki?



              Under normal circumstances, a signature would go here.

              Comment


              • #8
                Originally posted by DarquePervert View Post
                Two reasons:
                1. To avoid using an inverter. They are bulky & inefficient. Low-quality inverters are also more likely to introduce EMI interference (aka "noise") into your audio system.
                2. Most home/office monitors aren't as bright. They don't have to be, as they have to be read indoors, not in direct sunlight.
                for the first, i cant really disagree cause i dont know (althoug, inefficient, in like 20watt that a screen uses, is nothing)
                but on the second, you are completly wrong. home monitors, as long as they are gloss and not matt, are ultra bright. "lumens" are not everything when it comes to SEE the screen. car monitors have at best 250 contrast, when hoem screens have from 50.000 to ++++ making them very easy to be read. In my case, even with the sun reflecting on the screen, i can see very easy!!

                Comment


                • #9
                  Brightness is not the same as contrast, but if you reckon home monitors work fine in sunlight etc...

                  But efficiency has little to do with the load, though best efficiencies are usually at ~80-85% of rated output - especially for inverters.
                  But inverters often have a high no-load draw - eg, 10W for a 100W or 150W inverter plus the "copper" inefficiencies (those related to the load).
                  I doubt you'd get less than 30% inefficiency for an inverter at 20W (and whatever draw when in stand-by = idling, eg, 10W, or 5W or 20W?) whereas a dc-dc converter is likely to still be under 10% inefficient and have negligible draw when idling.

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                  • #10
                    Originally posted by OldSpark View Post
                    Brightness is not the same as contrast, but if you reckon home monitors work fine in sunlight etc...
                    contrast is no the same as brightness, yes, thats why i sed "when you try to see the screen". cause in two screens with same brightness, when you try to see text on the screen, with low contrast, the text is ruined by sun, but with great contrast, its still see-able . dont take it as "They are brigheter", take it as "they are more sun-readable" !!

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                    • #11
                      i think it's a big waste of energy to use an inverter.

                      hit me if im wrong, but all lcd displays/controler work with low DC <24v.
                      there are also models with external ac/dc converters. so why not remove the ac/dc converter and replace it with some good dc/dc converter?

                      about the laptop screens, this isn't impossible, but most people don't want to bother with lvds and getting an working controler board. in germany/austria there is a "do it yourself beamer"-scene which uses this stuff, this is where i bought a 10" WXGA Laptop Screen with Controller.

                      this is how such sets look like: http://www.beamer-selbstbau.de/produ...ontroller.html

                      Comment


                      • #12
                        Yes. Long gone are the days of requiring HV supplies for monitors. Even when components need HV, they are now usually supplied by onboard converters (that's much cheaper if nothing else).

                        And yeah - most "AC" devices are usually 12V DC or less internally though 24V DC is not uncommon.

                        I was going to re-reply about contrast and and that "home" screens may not have the correct polarisation nor be suitably ruggedised for automotive use (vibration, heat. humidity, UV) and suggest bypassing a display's ac-dc conversion.
                        As I stated or inferred earlier - at best, inverters usually add AT LEAST 20% inefficiency (losses) compared to using DC or dc-dc converters.

                        Comment


                        • #13
                          Originally posted by settra View Post
                          for the first, i cant really disagree cause i dont know (althoug, inefficient, in like 20watt that a screen uses, is nothing)
                          but on the second, you are completly wrong. home monitors, as long as they are gloss and not matt, are ultra bright. "lumens" are not everything when it comes to SEE the screen. car monitors have at best 250 contrast, when hoem screens have from 50.000 to ++++ making them very easy to be read. In my case, even with the sun reflecting on the screen, i can see very easy!!
                          dynamic contrast vs static contrast are totally different. Static contrast is what you need to look at, not dynamic which is what the manufactures use to suck people in to buying their screens, which is very misleading... Contrast is not the be all and end all, its about the gamma curve that gives you the better picture quality.

                          if anything, use a laptop panel and driver board, as its been mentioned why waste power upscaling dc to ac using an invertor, to a screen which drops it from ac down to dc.. more efficent and smarter ways to do it, just not the easiest.
                          Last edited by ephect; 05-19-2013, 06:10 PM.
                          ------------------------------------------
                          Originally posted by ClockWorK
                          Remember, as soon as you make something idiot-proof, they will come out with a better idiot.
                          ------------------------------------------

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                          • #14
                            I always wondered.why people throw around big words like inefficiency.

                            20% less efficient then a dc.to dc converter....

                            lets do some math.

                            20 watt lcd. 20% inefficiency using an inverter...

                            24 watts.... who's going to notice the extra 4 watts? your talking less then 1/3 of an amp, assuming 12 v's .
                            Progress,.... that is what I keep forgetting ;)
                            planning_[++++++++++]. 110%
                            parts___[++++++----] around 60%
                            install___[-----------] -9,000%

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                            • #15
                              You are forgetting the inverter overhead, ie its idling current.
                              It may be small, and dc-dc converters may have their equivalent, but many inverter efficiencies are quoted at a given output to disguise the overhead. EG - a 300W inverter at 80% of full load may have a 90% conversion efficiency, but then subtract the 10% inefficiency cause by its 30W constant loss at ANY output load.
                              That does depend on design, but dc-dc converters often have a very small overhead and hence have a higher and flatter efficiency (curve) throughout its 1-100% load range.

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