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Thread: Why are DC-DC power supplied so expensive?

  1. #11
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    In reply to lowlife's comment of "why would *anyone* use an inverter"

    Why the hell would anyone use DC-DC.. inverters are cheap as ****.. and as for power supplies.. they cost like $5.. with an inverter you don't have to **** with anything.. you just plug it in and go.. if you wanna remove it and use it in the house.. no problems.. why get DC-DC and run into problems about accessories not working.. at least with an inverter everything will work..

  2. #12
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    I totally agree with you "inmytree" I think that they are much easier to use, plus if you have a place to hide them, why not, it saves a lot of time money and trouble!

  3. #13
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    in response to inmytree, Not all countries use 110v, in Australia we have 240v. That means you are stepping 12VDC up to 240VAC then from 240VAC back to 12VDC etc.An inverter over here for this sort of application costs **** loads of money and they are very lossy, so I say **** inverters build (or buy) DC-DC.
    Also, I use a car battery charger to to run my player on the rare occasion that it is out of the car

  4. #14
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    Most power supplies (at least mine) has a swich that lets you choose between 230 or 115V, so you can use an american inverter.

    I live in Norway (230V)

  5. #15
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    This is kind off tangent to what we have been talking about but what's the feasiblity of using a solar-powered power supply?

    Presumably, you'd have a back-up battery to provide power when there was no sun.

    You could let your car bake all day in the sun while you're at work and (re)charge up the battery.

    But I'm sure going the solar-power route would be some major bucks....

  6. #16
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    In reply to inmytree, why not use an inverter? Why not just buy a CD burner and make custom CDs for an aftermarket CD changer for your car? It's a whole lot easier than cobbling an old PC together, duct taping a case to hold it, stuffing it in some remote corner of your car, finding a place for a control pad and LCD, then screwing with software! It's the same principle! Why? The why to any of this home brew MP3 player stuff is the pride that comes from "I made that", not just the coolness of the system. It's the payoff of weeks of testing and trying that elicits the "Holy **** this thing really works!" response from the builder. The same is true for the DC-DC power supply, anyone can get an inverter, but building your own PSU is something else to be proud of! Before you knock someone else's idea, think about how you felt when your MP3 player started working. Besides inverters are very inefficient, you are going from 12-13VDC to 110/220VAC back down to +12/+5/-12/-5/3.3VDC. To me it's kinda of like backing up 30 foot to move ahead 40 foot. If you have to do it fine, but if there's a better way then why not take it! Besides, there are enough designs out there now that reliable DC-DC PSUs can replace the stock power supply with no effects on the computer.

  7. #17
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    Ya I hafta agree with you twins22. =) I kinda wish I woulda made my own. I was just too afraid of ******* up my $400 motherboard. Maybe I will still try to make one, but find some cheap 486 board I have laying around to test it out on. hehe.

    I guess all I was trying to say is, that for a little more money you can BUY a slick *** super small DC-DC converter that is way more efficient and a lot quieter than an inverter. Different strokes for different folks!

    LowLife

    <a href="http://www.sunflower.com/~jahelka/MobileMP3/">My Mobile MP3</a>

  8. #18
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    I have to agree with inmytree, I'm building my system with reusablility in mind also, thats why I decided to use an inverter, they are cheap, and if I ever get stuck and need to run some electrical device, I have an inverter in my car. Also I already had my inverter so it cost me nothing at all.
    To further extended my reusability instead of cutting the cigarette lighter adapter from my inverter to wire it up in my trunk, I purchased an accessories adapter (like a cigarette lighter, but its only for accessories that use a cigarette lighter adapter) cost me $8 at cdn tire. So now I not only have a reusable computer, I also have a reusable inverter which gives me more options to run other equipment, It also gives me a nice accessories adapter should I decide to use something else =)

    now if your going for fully involved professional with a custom case and all, then I'd say dc-dc, you have to look at the application.

    sure inverters have loss. hell they draw current even when there is no load. Also they generate heat which can add problems if you live in a really hot area.

    And for those Aussies that would be a major pain in the *** using an inverter ==))



  9. #19
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    Firstly in reply to snake bite:

    I also live in Australia and I don't consider $160AU for an 200W inverter from Jaycar Electronics a "****load of money".. to buy a DC-DC power supply costs a "****load" more than that.. I can tell you.. if you wanna make one.. sure.. but its gonna be a ***** and for no real advantage.. and as for your comment about inverters being "lossy".. thats just a load of crap.. my inverter stays pretty damn cool.. therefore there is no power loss via heat, so where else does all this power that is lost go?? Converting from AC-DC hardly looses any power at all..

    And in reply to twins22:

    Fair enough.. if you wanna have the satisfaction of making your own.. fine.. but the discussion started by talking about BUYING a DC-DC power supply.. which is an absolute waste of money.. the only ONE situation I can see it being an advantage is if you are really pressed for space.. but thats it..

    And to Alien8:

    As I said, I live in Australia and the inverter sure ain't a pain in the ***.. I just leave it on all the time, when my car gets turned on, the inverter and therefore the computer starts up.. when I turn the car off, the comptuer shuts off too.. its sweet..

    As for it drawing a current when there is no load.. it does, but its very very small and pretty much insignificant..



  10. #20
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    Inmytree, you are obviously very passionate about this inverter thing so Ill leave it alone. However I do tend to agree with twins22, if you are capable of putting a DC-DC together then do it. (mine cost me ~$30AUS and 2-3 hours to build, thats $130 cheaper than Jaycar.....$130 thats more than 4 cartons of beer).

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