Audio/video equipment?

[Tim Strommen]

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

[JerryH]

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.

[DrivingMissLazy]

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

[Busted Knuckle]

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 

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?               

[Busted Knuckle]

Oh yeah I know I'll pay for that last question some day! LOL But I just couldn't resist! LOL! BK 

[H3Jim]

BN,
The best one you can afford.

[John Z]

Hey BK - what are some brand names and sources for the HD monitors you mention?

[Tim Strommen]

...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.

Oh, a nifty "tool" for teaching about power quality is available at this website.  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

[DrivingMissLazy]

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