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PW60 In-car regulation

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  • PW60 In-car regulation

    Hi, guys!

    It's my first post here and I'll use it to share my happiness and ask 1 question.

    Fist of all, forgive my english, but we talk portuguese down here in Brazil!

    It's 8 years now I've started my carputer projetc. Yeah, EIGHT years. I saw born. At that time there wasn't epias, dc-dc PSUs and even LCDs was so rare (and expensive). I started with a PCChips M598LMR mobo and a 233mmx processor. But the project got stuck by the power. Nobreaks were so expensive too (or maybe my budget smaller :P).
    All that years passed and I've got a M810 with a Duron850 and a 600va nobreak. But got stuck with the LCD.

    Now, FINALLY I've found (and bought) an EPIA 800 and a PW60 as well. I was happy as hell once this stuff are so rare or so expensive here because the hi taxes (60% import fee over the produtc PLUS shipping).
    The two cost me something about 150US$!!
    Got a 8'' VGA-in LCD with built in TV-Tunner for another 150US$. Unfortunately no touch screen again because the cost (the only one I've found was about 550US$).

    So I started to play with the stuff. I know Epia 800 is a little poor on maths and video playing is hard to get, but I've got it running divx, and even dvd with no problems after some config and with the appropriate software.
    You'd say to get a Neemiah or something like that, but there is no way of doing that. They are not sold in here, and importing costs more than double the price you pay in your countries and our money is about 0.50US$ per R$1,00 so it makes it FOUR times more expensive than it's for you.
    I'm SO happy I've found ANY Epia here for a ressonable price.

    The PSU runs fine from a wall brick I have (modded AC PSU), but it's my love and pain. I've been reading all over internet (and mp3car foruns as well) that PW60 is not regulated (nor wide input).
    I'de love to have a M2 PSU, but can't find it and impoting stuff you already know

    So, the question is: There's any single way to regulate the car DC current to make it 12V constant? My Opel Tigra runs 14.1V with engine running and as low as 8V on engine start.
    I've tought of using 5 ou 6 7812 linear regulators (1A each) in parallel to do the job with the engine on. Step up for undervoltage is fine too, once I'd love to be capable of using the computer with the car turned off too.

    Thanks for the audience who had the patience to read all this :P

    Any help would be apreciatted (specially a free M2 PSU :P)

    Tigra Clube Brasil

  • #2
    PW60 In-car Regulation

    Damn... I wish it wasn't my first post

    I've wrote on before this, and it was huuuuuge. Took me 30min to write it. So the session expired and it's almost 2am down here in Brazil and I can't write it all again.
    So, forgive me but I'll start posting with a question:

    "There's any easy way to regulate the DC input of a car to a PW60 PSU?"

    It's impossible to change the PSU for another one once even PW60 was a real miracle to find here, and import costs makes things in here FOUR times expensivier than in USA ou Europe.
    I've tought of using 5 or 6 LM7812 voltage regulators to do the job with the engine on. Will it handle the job? There's any easy shchematic for something with step-up too? (using the carputer with the engine off would be SO fine)

    Any help would be REALLY appreciated (especially a M2 PSU :P)

    []s from Brazil!
    Tigra Clube Brasil


    • #3

      I am confused about this. So, you already have a device called PW60 and you want to power it with 12V?


      You just want to feed your computer regardless the state of engine with 12,5,3.3V respectively and the total power is 60W?

      In latter case I can help you perhaps, because I have built my own PS, because the small budget...
      Nothing special, one setpup for 12V and 3 stepdown for 5V,5Vsb,3.3V
      I used LM2679 5A variable output types.

      In first case you can use 7812, but select a more powerful one, for 2A. Care the heat dissipation...
      If you want to build a step-up for 12V/5A, that is more difficult, but not impossible.

      Have you got possibility to have a notebook adapter for 15V and after applying the 7812s?
      Alopecia perniciosa


      • #4
        Originally posted by will_santana View Post
        "There's any easy way to regulate the DC input of a car to a PW60 PSU?"
        Carnetix P1260

        And I merged your threads. You're subject to the newbie moderation that's supposed to be helping reduce spam.
        Have you looked in the FAQ yet?
        How about the Wiki?

        Under normal circumstances, a signature would go here.


        • #5
          thanks for the replies

          As you can see in the second post, the system has shown a error message after I tried to post the fist one and I posted the 2nd smaller one

          PW60 is a 12V unregulated PSU, bbslazs. The problems with it is handling he higher voltage with the engine on (once it don't regulate the 12v line) and dealing with the voltage drop of the batery after some time of use

          I'll follow your link, darquepervert and thanks for mergin the posts and excuseme for double posting (I'm administrator of the Tigra Clube Brasil forum and know how hard it is to keep things in order)

          Tigra Clube Brasil


          • #6
            I think in this case there are two opportunities:

            1. Using a DC-AC inverter and then an AC PC PSU. It is noisy, but quite simple (You transform the voltage into 220/110 and then use a simple old ATX unit.)

            2. Make a unique power supply specially for EPIA and forget that 60W gadget.
            You can use stepdown converters for 3.3 and 5V, without any problem. Fine and simple.
            For 12V it is a little bit tricky, because the voltage varies between 8-15V.
            I suggest to convert the voltage up to 15V with a simple setp-up and then use those 7812. An epia just needs some hundred milliamperes of 12V...

            Too many 'simple's...oh, sancta simplicitas
            Alopecia perniciosa


            • #7
              nice trick, bbalazs!!!
              any glues on step up ICs?
              I got some MAX787 and MAX788 from my antique project of buiding a Sproggy PSU. But once more, the stepup portion of the PSU was the problem

              I thougt of regulating the 12v line BEFORE the PW60 PSU, so I don't have to worry with the other voltages. Even that it cost me to build a powerfull regulator. Or maybe regulate just the 12V rail and leave the PSU handle the rest once it can deal with the 8v voltage drop.

              Tigra Clube Brasil


              • #8
                There is something must be wrong, I have tried this to send third time...

                Alopecia perniciosa


                • #9
                  by the way, one thing you might find useful:
                  That's a short guide on how I modified a PW-200 to split the 12v input into two different ones - one which feeds the 12v rail, and one which feeds all the other regulation sections (5v, 3.3v, etc). This means if you use an external 12v regulator to regulate the 12v rail, it only needs to drive the 12v rail, not the whole PC - you can feed the rest of the regulation sections with a regular unregulated 12v line. I would assume that a similar modification would be possible for your PW-60, if you decide to stay with it. The board I tested it with in the thread was an epia 800, and as you can see it reduced the load on the regulated 12v rail significantly.
                  But don't take it from me! here's a quote from a real, live newbie:
                  Originally posted by Viscouse
                  I am learning buttloads just by searching on this forum. I've learned 2 big things so far: 1-it's been done before, and 2-if it hasn't, there is a way to do it.


                  • #10
                    guys, thanks A LOT!!!

                    it's PERFECT and exactly what I need
                    I'll start studing the PW60 input to know where to cut the things. And with the bbalazss or evandude's designs of step-up regulators, I think it can be done

                    let me as one more question for each one:

                    evandude, in your mod on PW200, you use the regulated 12v source to feed ALL the PSU's lines or just the 12v line as u sugested?
                    I'm planning to regulate just the 12v line as you said and leave the PW60 do the rest with the unregulated input.
                    Just thinkin that in that case I should put the regulator AFTER the switch IC, so the regulator input would be the IC's output. Or is it better regulate the IC's input as you did and sync the power up of the both boards (PSU and Regulator) using the same power on switch?

                    bbalazss, The IC you're using is the TL949, right? And that withe thing just beside it? Is that a trimpot?

                    []s and thanks once more. U guys rulez!
                    Tigra Clube Brasil


                    • #11
                      Yes and yes. 494 and a potmeter 50K. That coil is from an old PC PS.
                      Alopecia perniciosa


                      • #12
                        Started quoting the IC's down here in Brazil. The TL494 and UC3843 are SO cheap! I'm glad to see there's a easy and affortable solution for my case.
                        The TL494 is cheapper, but the cost of UC3834 is not an issue at all

                        I think I'll go with bbalazs desing just because it looks simplier than evan's one.

                        Any special recomendation about that coil or can it be any PSU coil, bbalazs? I got a LOT of broken PSUs that I can savage for the coil or any other component needed. What's the other IC close to the 7812? I think it's the handwriten one in the schematic and it's kinda hard to read. The old printed value is BD246C. So I guess it's a transistor, but can't read the codes.

                        I think I'll need you guys to help me with tracking the 12v rail and the cut point in the PW60 itself. Just tooka quick look and couldn't find the switch IC. I'll look better and if still can't find it, I'll post some hi-res pics for you.

                        Forgive me for this much questions, but I'm really bad with analog desing (more the digital design dude myself)

                        Thanks a lot for the info and glad to see that there is good and competent people like you guys around!

                        Tigra Clube Brasil


                        • #13
                          My circuit works with the smaller 'choke' coil (or how it is called) of the ATX DC side. As I remember it was a 250W PSU.

                          I had to try and try, because I had no scope at all. Just two cheap multimeters. First I set the output voltage, and then I used the other one to measure the current on the primer side. I applied pure ohmic load on the secunder site. I was searching for the situation, when efficiency goes over 90%, that was enough for me.
                          You can also play with the oscillator freq (by resistor and capacitor).

                          Or ask a friend who is an electric engineer/techician or can calculate and measure the inductivity of that coil.

                          One of the black cube is BUK456 FET, the other one is the Schottky diode.
                          Sorry misleading you, there is no 7812 stabiliser yet. This circuit was just for test. I also use it, when I need higher voltage sometimes.
                          That thick wire behind is the 0,01 Ohm resistor to limit current.
                          Instead of transistor I used BUK456-60A FET, but you can use any recycled transistor for heavy load (5A or so). As you can see I also applied recycled capacitors....

                          Take care to form the common ground point (I suggest star-order), because current over some amperes cause weird things flowing 1-2cm...not the same than in the realm of computers...
                          Alopecia perniciosa


                          • #14
                            thanks for the fast reply

                            I'll do this (for the whole community benefit):

                            Take your schematic and put it in some software I got. Make a one-sided PCB with discrete components (SMD can be very tricky and hard do find and/or deal with)
                            Then I'll post the PCB for your aproval and changes it will need

                            Once it's done, then will be the time for the PW60 modding.... but that's another history!!!

                            Tigra Clube Brasil


                            • #15
                              Will, if you know, how much I hate to drill ) Therefore I used those smd components. They are also cheaper and easy to identify. Not bothering to check those silly color-code...
                              Alopecia perniciosa