BCM Community
Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: John Z on February 27, 2007, 08:14:25 AM
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I am about to start building and installing my entertainment system. I am wondering what you have found to work well. My first thought was to use home type 110 volt equipment for a DVD player and stereo receiver. Now i see auto type 12v systems that have AM/FM, CD, DVD, MP3 etc all built into one in-dash unit. I am thinking about using one of these with a 110volt LCD TV which will run off an inverter. Any thoughts from you would be appreciated as to what has or has not worked for you.
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My only thought in the all in one dash units are the good ones are all VERY expensive. The household type equipment usually is a little cheaper and is what I am going to go with. I'm using a car audio stereo/cd player and a home style DVD player and amplifier.
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Hey Brian, have you bought a tv yet for the coach? I am waiting for the digital turners to come down a bit in price,,, the analog ones sure are getting cheap. Wondering what type of mount system you are using or planning to use. I seem to remember seeing a tv with a vga input which would be nice for using with the computer too.
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I wrestled with some of these same decisions when I set up the A/V equipment in my 4104. I came to the conclusion that the best way to go for audio was to use a good quality car system. They sound good, are built for the temperature and vibration of mobile use, and running off 12 volts greatly simplifies things.
Although 10+ years old, my Sony head unit has tremendous flexibility through its Unilink controls. It ties into my 10 disk CD changer, and displays disk titles. I could add a second CD Changer if I wanted. There is a Unilink expansion box (Model XA-300) which has RCA jack auxillary inputs. I use these for running the TV's audio signal to speakers distributed through out the bus. I tie my iPod into this as well. The expansion box even has a USB port for connection to my PC. I use that for the Delorme GPS voice commands. One of the coolest features is Sony's remote stalk controller which I mounted to the side of the dash and lets me control everything from the driver's seat (Model RM-X4S). Check out Sony's Xplod website for more info on these specific items.
From a video equipment standpoint, what I currently have is ancient and I am in the process of redoing this. I have an old 9" TV that runs off 110 or 12 volts, like on the units you see for sale at a truck stop. I plan to replace it with an LCD flat panel (19-23") mounted to an adjustable articulated arm. I recently built something similar for a nursing home patient who is confined to a bed, and it turned out real nice. I believe there are some LCD panels that run directly off 12 VDC, and require a brick style transformer for home 110 VAC use. I need to look into this further, but it looks plausible that if properly protected/filtered, the house batteries could power the TV directly. I haven't decided whether I will use my laptop or a separate device as my DVD player.
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Hey Brian, have you bought a tv yet for the coach?
I'm using a Samsung 21" LCD tv. I tried to use a cheaper Sharp unit, but the blurring of moving objects was just too bad. I returned it and spent the extra $150 for a better unit. I don't have it mounted on a wall yet as I'm really not to that point, but do use it while traveling.
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WEC, thanks for the info on your system. I am inclined to head off in that direction also, as i like the compactness of a single unit to handle all audio/video chores. I will look around and research that Sony unit tonight, as it does sound nice. There really is no shortage of auto in-dash dvd sytems out there and the price has really come down. A salesman at best buy told me that he guessed most tvs are running on 12 volt internally. Not sure if it is worth it to open one up and check that out or not, but it sure would be nice to just go around the transformer they use to drop to 12 volt if it is true. Anyone know anything about this?
Brian, you have got the size tv i want to put in my coach also. I have avoided doing it because i can't decide if i want it mounted right behind the driver seat, or on the wall between the salon section and the kitchen. Both areas work out well.
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Hi John,
The Automotive systems are the way to go. Wayne and others above have detailed the reasons well.
Now, If they only would make a TV that can withstand heavy vibrations......
Nick-
Oh, Here is one of my bus systems
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Nick, what brand type of equipment is that? I see automotive monitors for sale, but they seem to only go up to about 13" size. And then i would need to buy a unit with a tv tuner built into it. They also allow VGA input from computers which would also be nice.
Have you had problems with the home type tv's? I would like to avoid any brands/types that are prone to giving problems. I suppose i can avoid the vibration/shock problem by leaving the thing sit on the couch until it is time to use it! :-\
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John:
I took a look at a number of the smaller 15-17" LCD panels at Best Buy and Circuit City earlier this month. It seems most had the AC cord running directly to the unit. However, a number of them used an external power supply (like a laptop computer). Of these, most had the jack on the back of the set labeled 12 VDC. I think I also saw one labeled 9 VDC. As you go up in screen size, the odds of having the AC adapter built into the set goes up. It may be possible to find something in the 19-23" range that still uses the external adapter.
As long as any surges or sags in the house batteries won't damage the set, it seems like the way I would want to go. For some reason I have a problem with taking the 12 VDC (+/-) from the house batteries, running it through an inverter to make 110 VAC, then running that through the set's adapter to turn it back into 12 VDC. Also, I know my present cheapo 9" set requires me to reprogram my active channel list everytime I disconnect/reconnect to AC power. This is a PITA which I could live without and sove with a battery direct connect.
I also will be making sure that any set I buy has a VGA connection for a PC, as well.
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Hi John,
My system is a Pioneer AVICN3, I'm able to send the DVD, NAV, and other inputs to my main 30" LCD TV along
with being able to view them on the 7.5" screen. My favorite feature besides nav traffic is, the back-up camra
can split the screen with the navigation to enable me to track both at the same time. eliminating a 2nd monitor for back-up.
Wayne is correct about the 12v DC input on some TV's, I just checked my 30" LCD and the power pak says 12v dc.
It's a Magnavox. Check out this thread on the new Pioneer all in one for half the price that I paid 1 1/2 years ago.
http://www.busconversions.com/bbs/index.php?topic=3442.0
Nick-
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I thought it was a toss up. I ended up with a high quality home system NAD surround sound home theater system. 'm very happy with it. It has a remote, so its not an issue that the unit is behid my when I'm driving. I have my entire CD collection with paylists on my Ipod, and I use that a lot while driving. That is very easy to hit the next button if I'm sck of a song in the playlist. I leave my inverter on all the time, but if I wanted to turn it off, that might be an issue where the 21v unit would shine.
At this time, I do not even have speakers hooked up to my in dash unit, a high quality Kenwood unit. I suspect that the tuner on an a unit made for cars is probably better and more likely to deal with multipath signal distortion better than a home unit, although I've been very happy with the NAD unit. Multipath distortion is where the unit has to distinguish between the original signal and reflectd ones such as ones that might be bounced off of tall buildings as you drive down a street. Dealing with a weak signal might also be an issue.
I have 5 speakers for the home theater, a 12v unit may not have as many options for movie sound as a home unit does.
I also have a powered subwoofer that really helps. Makes for much better response - that lower octave enriches teh listening experience, and by removing the need to reproduce that lower octave fromt eh main speakers, it allow them to function better as well. Of course, you can have a subwoofer with either kind of system.
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I think it should be pretty easy to open up a set, and find where it feeds out the 12vdc if that is what it is running on. I agree it sure does not make any sense to run 12v into an inverter and make 120v and then feed that into a tv that has to convert it back to 12 v in order to run. Why waste the capacity of your inverter doing something like that if it can be easily avoided? I imagine it would void the warranty at a big box store if it is opened though. Not sure that they would even know as i have not looked at doing that yet.
As for having to reprogram the active channels, when i was OTR the last couple weeks, it seems i had to do that every day almost anyway.
I have found an indash unit that plays AM/FM, CD, DVD, MP3 and a couple formats. It has 320 watts total for 4 channels, plus a powered outlet for a subwoofer. A fistful of input and output jacks plus remote. Using this means i have to buy a TV, not a monitor since this unit does not have a tv tuner in it. If i have problems finding a tv with vga input, then i will move up one notch and get the same unit with a tuner in it.
Nick your setup looks great! But it is beyond my budget for now. Can i ask where you mounted a 30" set? I can't even find space for a 20"!!!
H3Jim, i agree about the need for a sub for good sound. Have you wired in crossovers into your other speakers? I found that really makes a difference also for not much money, versus the combination speakers.
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I have a normal AM/FM cassette and CD player (car type) over the drivers seat with two speakers up front (piezo tweeters and 12" woofers) and half way back 6x9 three way Blaupunct. In the back I have a regular house type stereo system with speakers on either side of the bed (piezo tweeter and 10" woofers). It is an AM/FM receiver, twin cassette deck, VCR, DVD, 5-CD changer. My TV's are a giant 9" in the bedroom and a 13" up front-old style CRT TV's that are real workhorses. When digital comes into play, I'll just get the converter for my old analog TV's. Good Luck, TomC
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John,
The NAD home theater receiver system has a built in crossover, so it doesn't even send a signal over 80 hz to the main speakers when set up for a subwoofer.
RE: video out, get a monitor that has HDMI inputs, then you can send video from your computer as well.
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Hi Jim, yep the indash unit has a separate output for subwoofer too. But i am putting crossovers in between separate tweeter and midrange speakers as well. You can really get some nice distance and separation that way. I am not familiar with the HDMI input you mention from a pc. Can you tell me more about that? TIA
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Not much to say, its digital, its the new standard, and already they are talking about replacing it. Cables are prohibitively expensive. It was cheaper for me to buy a second DVD player for the back than to buy the cable to run from the front to the TV in the bedroom.
Maybe google it.
What is HDMI?
HDMI (High-Definition Multimedia Interface) is the first industry-supported, uncompressed, all-digital audio/video interface. HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, and A/V receiver and an audio and/or video monitor, such as a digital television (DTV).
HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio, with bandwidth to spare to accommodate future enhancements and requirements.
Who supports HDMI?
The HDMI Founders include leading consumer electronics manufacturers Hitachi, Matsushita Electric Industrial (Panasonic), Philips, Sony, Thomson (RCA), Toshiba, and Silicon Image. Digital Content Protection, LLC (a subsidiary of Intel) is providing High-bandwidth Digital Content Protection (HDCP) for HDMI. In addition, HDMI has the support of major motion picture producers Fox and Universal, and system operators DirecTV, EchoStar (Dish Network) as well as CableLabs.
How do consumers benefit from HDMI?
The new HDMI digital interconnect provides:
Superior, uncompressed digital video and audio quality
Simple, user-friendly connector that replaces the maze of cabling behind the entertainment center
Integrated remote control
A popular interface enabling the transmission of high-definition content. HDMI opens the floodgate of digital content from major motion picture producers
When will the HDMI specification be released?
The HDMI 1.0 specification is available now. CE manufacturers may begin designing products incorporating the HDMI standard-addressing consumer demand for HD programming and for DTVs that display this content.
When will prototypes of HDMI products be available?
HDMI-based prototype devices were first demonstrated at CES in January 2003. The CE industry is currently transitioning from DVI to HDMI connections. Backward- compatible with the DVI 1.0 specification, HDMI enables both multi-channel digital audio and uncompressed video transmission over a single cable and connector, and in combination with HDCP addresses content providers' requirement for a secure interface to protect high-quality content from unauthorized redistribution.
What is the life expectancy of HDMI?
HDTV uses less than 1/2 of HDMI's available 5 Gbps bandwidth. With capacity to spare, HDMI can incorporate new technology advancements and capabilities long into the foreseeable future.
Does HDMI provide a secure interface?
HDMI, when used in combination with HDCP, provides a secure audio/video interface that meets the security requirements of content providers and systems operators.
What are the advantages of HDMI over existing analog interfaces such as composite, S-Video and component video?
Quality HDMI transfers uncompressed digital audio and video for the highest, crispest image quality.
All Digital HDMI ensures an all-digital rendering of video without the losses associated with analog interfaces and their unnecessary digital-to-analog conversions.
Low-cost HDMI provides the quality and functionality of a digital interface while also supporting uncompressed video formats in a simple, cost-effective manner.
Audio HDMI supports multiple audio formats, from standard stereo to multi-channel surround-sound.
Ease-of-use HDMI combines video and multi-channel audio into a single cable, eliminating the cost, complexity, and confusion of multiple cables currently used in A/V systems.
Intelligence HDMI supports communication between the video source (such as a DVD player) and the DTV, enabling new functionality.
Is HDMI backward-compatible with DVI (Digital Visual Interface)?
Yes, HDMI is fully backward-compatible with DVI using the CEA-861 profile for DTVs. HDMI DTVs will display video received from existing DVI-equipped products, and DVI-equipped TVs will display video from HDMI sources.
Will current HD TVs and set-top boxes using DVI-HDTV be compatible with HDMI devices?
Yes. Currently there are TVs with DVI-HDTV inputs available from a variety of manufacturers. Those devices will be compatible with future HDMI-equipped products.
What types of video does HDMI support?
HDMI has the capacity to support existing high-definition video formats (720p, 1080i, and even 1080p). It also has the flexibility to support enhanced definition formats such as 480p, as well as standard definition formats such as NTSC or PAL.
Does HDMI accommodate long cable lengths?
Yes. HDMI technology has been designed to use standard copper cable construction at long lengths. In order to allow cable manufacturers to improve their products through the use of new technologies, HDMI specifies the required performance of a cable but does not specify a maximum cable length. Cables are expected to be lengths of up to 15 meters. As semiconductor technology improves, even longer stretches can be reached with fiber optic cables, and with active cable technologies such as amplifiers or repeaters.
5 Things You Need To Know About 1080p And HDMI™
1. Why all the hoopla about 1080p? Most early adopters saw no improvement from their "up-converting" DVD players, even after going digital with HDMI™. Why? Because all they were really seeing was enhanced 480p on a 1080i display. The early hype about 1080p made us think it was the next big thing. Is it? New HDTVs that are "full HD 1080p" are shipping now so let's take a look at the top 5 reasons to go 1080p.
1. How much better is 1080p than 720p?
225%! It's a huge difference. The soundtrack also improves by 50% with the new totally lossless, bit-for-bit Dolby True HD and DTS Master HD multi-channel audio content.
2. Is this content available now?
Yes. It is exclusively available on Blu-ray disc players, soon to be on Playstation 3 (Blu-ray format) and 2nd generation HD DVD players. These two HD disc formats were created to deliver the 1080p experience to HDTV enthusiasts. The players decode Dolby True HD and DTS Master HD so you dont need a new preamp or receiver. Just feed the PCM output of the player to PCM input on your audio system and get ready to experience the widest dynamic range of any audio content in history.
3. Do I have to use an HDMI™ connection to get 1080p?
Yes. HDMI™ is the only way for two good reasons. First, it's digital all the way with no conversion or compression. Second, its protected by HDCP, the studios' way of keeping the best version of its copyrighted content protected from piracy. The players will not ouput 1080p from the component RGB output, only 480p, the current DVD standard.
4. Do I need v1.3 HDMI™ in order to see the real 1080p or hear the Dolby True HD/DTS Master HD soundtrack?
No. v1.3 HDMI™ (see chart above) was released as a specification "framework" last summer for hardware and software creators who are now beginning to work on the next "next" generation of HD called 1440p. v1.3 products have not yet begun to ship and there is no reason to wait for that. v1.2 HDMI™ will handle all the data at 1080p and the soundtracks too, with plenty of headroom to spare. No need to panic about this. What you have now, even if its v1.1 HDMI™ will work fine with 1080p.
5. What will I need to make 1080p work in my existing system?
PureLink™. In order to view and distribute multiple 1080p sources to multiple 1080p displays, you will need a switching and distribution system capable or delivering 1080p video with no data errors to your new 1080p display, while at the same time routing your HD audio content to your legacy receiver or preamp. To our knowledge, PureLink™ makes the only devices of this kind with full HDCP support on every output. This is important because the studios are watching for piracy of this new generation of content and intend to vigorously prosecute illegal downloaders, just as the music industry did in the Napster case. PureLink™'s models are legal. Be sure to ask the vendor you buy from for a written guarantee that you will be safe from any legal action taken by the studios. PureLink™ is the only brand that puts this in writing for your protection because we are the only company thus far to do it according to the HDCP mandate.
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Thanks Jim for the info. That is all new stuff to me, so i will have to reread it later tonight and try to digest it. I have to build my cabinet first, then install the head unit and speakers. I am waiting until June probably to buy the new tv,, i will just keep using my old 13" until then. I think June is the official date all sets sold have to have digital tuners... or is that the date the broadcasts all switch to digital? Not sure right now which is which. My daughter wants the bus to take her and a couple friends to Mexico in June for a couple weeks, so will need the new one permanently mounted for that trip!
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H3Jim
I have no idea what you were talking about, its Waaaayy over my head.
I have been looking for quite a while for a system that is pretty much all in one. Here is what I have been contemplating.
I plan to install an ONKYO CS-V720s mini shelf system. It has everything that I need and more, and its reviews are great. I have heard one set up in an electronics store and the sound is much better than you would expect from a small package.
In case the link dosn't work it is a DVD player, CD player, AM-FM receiver, Sattelite radio ready, and its Ipod ready. I plan to hook it to my 20" SVA LCD TV / Monitor through the house inverter.
If I have issues with the CD player going down the road, I will just use my Pioneer head unit that is already installed.
JimCallaghan
http://www.shoponkyo.com/detail.cfm?productid=CS-V720S&modelid=8&group_id=1&detail=1&ext_war=1
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Jim - Great info on HDMI (I work for Anchor Bay, the makers of the DVDO video scalers, and scaling/deinterlacing ICs). Do you have the web-link for the last half of what you posted (looks like somehting to do with PureLink)?
All,
Considering the requested feature set, I think it would be wise for me to mention (despite some likely groans...), that a "Car-puter" would suit all of these needs and then some. There are several manufactureres who are making Mini/Micro-ITX (not ATX) and even "Nano-ITX" motherboards which will run full versions of Windows or Linux/Unix (what ever your favorite is...), yet draw very little power (less than 100Watts). With the appropriate hardware these may have a 7" touch screen (like the in-dash head units), GPS via serial or USB, Wireless Internet (either WiFi or Cellular), MP3 playing (iTunes, Winamp, Windows Media Player, etc.), DVD playing (Windows Media Center, Power DVD, WinDVD, etc.), TV and FM radio (with USB input dongles), data logging and storage of trip information (MS Excel), and what ever else your imagination can stick in a PC.
By consolidating the PC/entertainment system into a Car-puter, you can reduce you space utilization, and with a VGA switch-box and a USB console extender, you can place a second "terminal" (Monitor, Keyboard, Mouse) in a place on-board that is more comfortable to use while in station (including USB Floppy and CD or DVD drives).
There are a bunch of companies making 12 and 24volt DC "DC-to-DC" power supplies which will run right off the battery (so that you don't need to add the "loss" of the inverter), and with a hacked-up RF wireless multimedia keyboard - you can cram the Windows Multimedia buttons somewhere on the steering wheel, just like the expensive wireless remotes some of these head units offer (which will give you volume, mute, and player controls). By having the Car-Puter hooked up to another multimedia keyboard (with USB you can have as many as you want), you can access the power state buttons to automatically "sleep" and "resume" the computer with some simple circuitry upon starting and shutting down the rig's engine.
Just a thought for 'yall...
Cheers!
-Tim
P.S. If you know enough about Windows XP, you can use the included "Briefcase" function to sync up your home "desktop" MP3, Wave, AAC, or even DVD "VOB" files with the bus "car-puter" collection if a wireless connection detects your home's wireless access point. This way, you don't have to manually carry your data to your bus before trips, you just park your bus with the computer on, and let it "sync up before shutdown" (so it turns off when it's done). -T
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Tim,
These "Car-Puters" sound interesting. You wouldn't happen to have and brand names and model numbers would you?
I use two full size towers right now, (his and hers), but they do take up a lot of room. I'd like to downsize, but don't want to
use laptops.
Thanks,
Dallas
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Tim, I just googled HDMI and it was on the first page. I thought it was better to cut and paste than make him go look.
No doubt our electronics will evolve a lot over the next years, and the pace is accelerating.
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Thanks Jim. Actually, the reason I asked was some of the last half of the stuff for the "PureLink" is utter BS (HDMI 1.3 is the only version that supports Dolby True-HD, and dts-HD) ;D I want to point this stuff out to the guys at Silicon Image (who designed the interface). It doesn't reflect negatively on you - but it does show that even on a manufacturer-published website some Marketing/Sales groups produce a bunch of inacurate or misleading information and present it as "fact". This is more (in my opinion) a reflection of the fairly low consumer knowledge about HDMI and the associated HDCP digital encryption that's used - coupled with a rediculously loose HDMI "standard" (where about 50% or more of the interface features are "optional" - thus capabilites are further mis-quoted, or not guarantee-able).
Dallas,
VIA, has been doing miniature consolidated mainboards for about five years now (they were the first, and they are based about 6 miles away from me in Fremont, CA). The Epia Nano-ITX board is the smallest board on the market at 12cm square! (http://www.via.com.tw/en/products/mainboards/motherboards.jsp?motherboard_id=221) This is about the size of a CD, and has CPU, Video controller, Network controller, Sound controller, IDE and SATA harddrive controller, TV out encoder (this is additional to the VGA out), USB Controller, and a jack that allows either a DVI or LVDS video output to be used for digital displays (instead of VGA).
In the pipe is the new Pico-ITX (Epia PX) main board which measures a tiny 100mm x 72mm. (http://www.mini-itx.com/2007/01/18/via-demonstrate-epia-px-at-ces)
Of course VIA isn't the only game in town now, and others make boards that support Athalon or Pentium processors - Albatron actually has a Mini-ITX board that supports the newest AM2-socket AMD micros, with DDR2 memory, and HDMI output. (http://www.hardwarezone.com/news/view.php?id=6704&cid=4)
For system builders/retailers,
Mini-box is one of the popular system integrators. (http://www.mini-box.com/site/index.html)
MP3Car is a user's group for in-dash PCs (Car-puters), but they sell them too. (http://store.mp3car.com/SearchResults.asp?Cat=78)
For screens, Xenarc makes a 7" touch LCD monitor, both a swivel/pedistal mount, and a slide-out/flip-up single din type (like the finished head units do) (http://www.xenarc.com/product/700IDT.html)
Xenarc also makes some PC's. (http://www.xenarc.com/product/index-pc.html)
If you're looking for cases to build your own, Travala makes some good ones that are fairly compact. (http://www.travla.com/Products/mini-ITXCase.html)
I think my favorite web-store for mini/nano-itx stuff is "Logic Supply". (http://www.logicsupply.com/index.php)
Logic Supply has an almost comically small power supply (but it still does the job at 120watts!) (http://www.logicsupply.com/product_info.php/products_id/505), and they offer a few other configurations and power ratings.
Hope 'yall find this interesting and useful.
Cheers!
-Tim
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Thanks, Tim!
I've ben out of the system building/ computer repair business for a few years.
I'll have to look into building one of the systems. It would certainly take up a lot less space, considering the board is the size of 2 packs of cigarettes!
Dallas
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And Thanks Tim for not jumping all over me, but for quietly correcting the misinformation I helped spread. It helps make this board a great place to be.
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No problem guys,
and Jim - I try to keep it positive and acurate unless someone is suggestion something that is blatantly unsafe (otherwise, a reader might think a post is an instruction manual, where all aspects of the task - including safety and liability were considered). I'm sure many readers may not have had some of the frightening experiences of the danger associated with a 40K-lbs vehicle. I try not to point fingers or trample people whenever possible, especially if one is paraphrasing another source ;D.
Cheers!
-Tim
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I'm all for running 12 volt equipment on 12 volts vs an inverter and 110 volts. The only issue I can think of is since when has a 12 volt vehicle system been 12 volts? Don't they charge at 13.8 to 14.3 or something like that? Several pieces of automobile audio equipment I've owned have power output rated (in watts) with a 12 volt input and a 13.8 input, so I know it has some effect. Are the home LCD's as tolerant of the higher voltages? If one were to use a 24 volt to 12 volt converter / regulator, that would probably eliminate the issue, for those with 24 volt elec. systems. There are numerous cheapo 12 volt inverters that could easily handle an LCD TV, even if the TV's adapter did convert back to 12 volts. I probably need to connect an LCD monitor to one of my small inverters and check the DC current draw with the monitor turned off. Surely those 100 watt inverters don't pull much with esentially no load. I guess I'm wondering how many have run TV's that require a 12 volt input reliably directly from the bus' elec. system for any length of time.
David
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I think you will find that there is no such thing as a piece of 12 volt equipment. That is a nominal voltage for general talking purposes. No automobile ever was rated at an actual 12 volts DC. The same for the 24 volts you mentioned. The actual measured DC voltage is closer to 28 volts instead of 24.
Each cell in a six cell, 12 volt battery is rated at a nominal 2.3 volts per cell. This comes out to 13.8 volts at full charge.
Richard
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It's typical to find a +/-5% tolerance with respect to the input supply of most consumer gear.
For 12VDC, this would be +5% (or 12 x 1.05 = 12.6Volts) to -5% (or 12 x .95 = 11.4Volts). Anything outside this range (positive) will burn up the internal power supply or (negative) cause the unit to not function properly/at-all.
There are 24-to-12 volt converters out there - but I'm not sure how well the off-the-shelf units deal with voltage sag (as the battery discharges or a stater is cranked). Some I'm certain are designed to maintain operation well out of spec.
With an inverter, you'll lose roughly 25% of the rating in the conversion (this is an "addative loss", as in - you add it to the rating to derrive the total load on the DC input wires). Some inverters are fitted with a dual inverter, one is a high power inverter (good for the specefied rating of the device), and the other is a low power "sense" inverter (for detecting when a load is turned on). In the case of an "El-Cheapo" inverter, it will drive the output side of the inverter no matter what is being drawn (and that roughly 25% loss will persist despite not actually powering anything).
If you have an LCD display with a good standby supply - you'll be able to tune the good inverter's load detection feature to only kick on the high power portion when the back-light is turned on for use (the CCFL backlights are the power hungry part of an LCD).
Imagine running a 250Watt Inverter with the LCD "off" - if it is still losing about 25% (250 x .25 = 62.5Watts), that's like leaving a headlight on...
If you go the DC-to-DC converter route - consider that you may need to add power filtration, as most household product power supplies aren't designed to deal with alternator noise ;).
Cheers!
-Tim
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Tim, if what you say is correct, then every 12 volt item in a vehicle would be ruined as soon as the vehicle is started and the alternator starts charging. The lowest charge voltage that I have ever seen recommended is 13.6-13.8 volts. 12.6 volts is significantly below the float /charge voltage of any 12 volt vehicle. In fact if the vehicle is running and the voltage is only 12.6 volts, then the alternator is not working.
Richard
It's typical to find a +/-5% tolerance with respect to the input supply of most consumer gear.
For 12VDC, this would be +5% (or 12 x 1.05 = 12.6Volts) to -5% (or 12 x .95 = 11.4Volts). Anything outside this range (positive) will burn up the internal power supply or (negative) cause the unit to not function properly/at-all.
There are 24-to-12 volt converters out there - but I'm not sure how well the off-the-shelf units deal with voltage sag (as the battery discharges or a strater is cranked). Some I'm certain are designed to maintain operation well out of spec.
With an inverter, you'll lose roughly 25% of the rating in the conversion (this is an "addative loss", as in - you add it to the rating to derrive the total load on the DC input wires). Some inverters are fitted with a dual inverter, one is a high power inverter (good for the specefied rating of the device), and the other is a low power "sense" inverter (for detecting when a load is turned on). In the case of an "El-Cheapo" inverter, it will drive the output side of the inverter no matter what is being drawn (and that roughly 25% loss will persist despite not actually powering anything).
If you have an LCD display with a good standby supply - you'll be able to tune the good inverter's load detection feature to only kick on the high power portion when the back-light is turned on for use (the CCFL backlights are the power hungry part of an LCD).
Imagine running a 250Watt Inverter with the LCD "off" - if it is still losing about 25% (250 x .25 = 62.5Watts), that's like leaving a headlight on...
If you go the DC-to-DC converter route - consider that you may need to add power filtration, as most household product power supplies aren't designed to deal with alternator noise ;).
Cheers!
-Tim
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I think radios and TV's that are desinged for vehicles would be ok, as they would take the charge voltage into account. I think Tim may be talking about using a monitor or other piece of equipment that uses a nomial 12 volts, and you are tapping into the bus batteries to power it. Two very different scenarios.
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Yeah - I guess I should've been a little more clear (Jim is correct in interppreting my information):
Household devices (the "consumer gear" I labeled) are devices that are primarily designed to be used within a static (non-motorhome) residence - typically derriving it's primary power from A/C line (supplied by a large, remote power station - like PG&E or SoCal Edison, etc. @ 120VAC) otherwise a non-automotive device.
An "automotive deivce" is a piece of equipment that was originally designed and sold to be used in a moving vehicle, and powered by its internally created power source (Alternator/Battery @ 12/24VDC).
A consumer device (120VAC static household) which requires a low-voltage step down and AC-to-DC rectification, is typically designed to opperate within the global power standards 100-240VAC @ 50-60Hz. They are also designed to filter out high-frequency conducted EMI/RFI and other voltage transients (voltage sags, spikes, etc) because there is a lot of margin between the converted power and the input power.
When a consumer device has an external power supply, correct operation can only be guaranteed while powered by an automotive supply (i.e. specifically not what it was designed to do) if the automotive power supply matches the design specifications of the output on the A/C power supply.
Automotive specific hardware, has a more robust power supply design - and they are always designed for a specific "nominal" voltage (the two most common are 12 volts and 24 volts). An automotive voltage has huge swings in comparison to an A/C "line powered - consumer device". (be gentle guys about this part - it's a rough example) A 12 volt automotive systems can experience a low of 6 volts during starter cranking, and will level off around 14 volts during charging. A 24 volt system can droop to 16 volts during starting, and will rise to around 29/30 volts during charging.
Automotive gear also has to deal with very close loudly-emissive (RFI) sources. These include the alternator itself, and blower motors, CB radios, etc.
My original comment above still holds true - in spite of my vagueness. The use of a consumer (household) product in an automotive enviroment will always take some careful consideration and planning - and when modifying a device to operate outside it's originally intended/design conditions (like circumventing the A/C power pack), there is a significant risk of making a small mistake that destroys the device very quickly.
Cheers!
-Tim
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I'd do an automotive type unit for sure. Are far as the medium (8-track, cassette, cd, etc.). Ok, first ... what's a cassette? That's on the way to the same home of the 8-track. Whatever you put in, make sure it has input from (for) an iPod. iPod ... that's the way to go. I got a Nano this year, only a 4Gb unit, holds about 1,000 songs -- enough for me. I plug it into my car type radio, where it has AM/FM, CD, and Aux option. Also has satellite radio.
Jerry H.
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Thanks for the clarification Tim. That sounds much better. Do you by chance know what the standard allowable variation for the utility power is? ie. is it 120 volts +5 -10 or what? I really do not remember.
Richard
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Wow, ya'll just blew what was left of my low-tech mind! LOL! All I can add to any of this is people always question the cost of our video systems. But I know of several systems that have been trouble free in motorcoach use (translated = rough service) for 7+ yrs! I also know of operators who'll constantly replace "cheap monitors" that break from the vibrations and abuse of being in a motorcoach several times a yr. My opinion is it's better to spend $ 4-5,000.00 on having a system professionally installed using the heavy duty components and going 10? yrs trouble free. Than to spend $2,000.00 give/take on a system you have to spend several days installing yourself, and then spending at least another $1,000. a yr on replacing those cheap monitors, DVD/VCP's and etc. (not counting labor time). Also not to mention p_____ off customers because the video system either didn't work at all or crapped out in the middle of their trip!
Ok I know none of this really relates to your conversions, or does it? Well in a way it does, because if you buy the heavy duty monitors they should last you a life time of trouble free service compared to always having to fool with another crapped out monitor! FWIW just my own opinion BK ;D
PS some day I'll start on a conversion and have all the worries ya'll have, by the way anybody know which bus is the best base for a conversion?
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Oh yeah I know I'll pay for that last question some day! LOL But I just couldn't resist! LOL! BK ;D
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BN,
The best one you can afford.
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Hey BK - what are some brand names and sources for the HD monitors you mention?
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...Do you by chance know what the standard allowable variation for the utility power is? ie. is it 120 volts +5 -10 or what? I really do not remember...
In North America, the standard design specification is +/-10% of nominal (120volts), with a guaranteed transmission Quality of Service specified at +/-5%. This is guided by the North American Energy Standards Board (http://www.naesb.org/).
Oh, a nifty "tool" for teaching about power quality is available at this website (http://www.powerstandards.com/PQTeachingToyIndex.htm). They are also a good resource for power quality standards and power quality monitoring tools and devices.
...I know of operators who'll constantly replace "cheap monitors" that break from the vibrations and abuse of being in a motorcoach several times a yr. My opinion is it's better to spend $ 4-5,000.00 on having a system professionally installed using the heavy duty components and going 10? yrs trouble free...
I used to do car audio installs (typically a harsher environment due to smaller vehicle-mass and thus greater suceptability to road vibrations). What I found was that there was little physical differrence in the actual device's mechanical design - but the placement of a given device had a great "impact" (forgive the punn) on the lifetime of the device. If an LCD screen was hardmounted to the chassis or a fixed apendage - the LCD (or its CCFL backlight) was more likely to break over time than a monitor mounted in a padded (and thus mechanically isolated) headrest.
If you have nothing but time, space, and money - you can build a shock mount for an entertainment system that will absorb most of the transient shock to the devices and will reduce the absorbed vibration a bit too. This will add life to a household device (but there are always tradeoffs).
Cheers!
-Tim
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Thanks for the info Tim. Sure wish I would have had that power quality tool available back in the 80's/90's when I was manufacturing and selling Power Quality equipment. I gave a lot of PQ seminars all over the country but never saw a tool like that available. To be fair I guess I should indicate that there was not an Internet then either. LOL
Richard