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Thread: DW 9a sst90 driver for automotive use....

  1. #1

    Default DW 9a sst90 driver for automotive use....

    Can anyone clearly point out the components that I will need to use the DW 9a, sst90 driver for automotive use? It has input voltage range acceptable for automotive use but there is something else I need to keep from tearing it up. I would really appreciate it.

    Thanks

  2. #2
    Flashaholic* AnAppleSnail's Avatar
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    Default Re: DW 9a sst90 driver for automotive use....

    You aren't planning on making LED headlights, are you? That is illegal, unsafe, and against forum rules.

    If this is the product in question:
    pdf
    7v-22v input

    Then electrically speaking you'll just need wires and a switch. Note that this could suck your car battery down to about 7V, which will strand you if you forget to cut it off.

    You will also need optics, a heatsink for the LED, and probably heavy wires, 14-12 gauge.

    Edit: Further, I do not know how to spec you a filter capacitor for automotive use.
    Last edited by AnAppleSnail; 02-15-2012 at 12:11 PM.
    My biggest light-hog is my camera.

  3. #3

    Default Re: DW 9a sst90 driver for automotive use....

    Quote Originally Posted by AnAppleSnail View Post
    You aren't planning on making LED headlights, are you? That is illegal, unsafe, and against forum rules.

    If this is the product in question:
    pdf
    7v-22v input

    Then electrically speaking you'll just need wires and a switch. Note that this could suck your car battery down to about 7V, which will strand you if you forget to cut it off.

    You will also need optics, a heatsink for the LED, and probably heavy wires, 14-12 gauge.

    Edit: Further, I do not know how to spec you a filter capacitor for automotive use.
    No I am not doing that. and yes that is the product in question.

  4. #4

  5. #5

    Default Re: DW 9a sst90 driver for automotive use....

    I saw your idea on that and it sounds great problem is I have NO clue where to get that stuff. Can you give me a link for everything I need? I am lost on this stuff... I can put anything together I just don't understand how all this stuff works.

  6. #6

  7. #7

    Default Re: DW 9a sst90 driver for automotive use....

    I see your diagram in the link. Is that how I would use these parts? Is there a more basic diagram that has everything clearly listed and what is what?

  8. #8

    Default Re: DW 9a sst90 driver for automotive use....

    Sorry to jack your thread. I will be using xml led for an automobile application, I was wondering would the filter work with Der Wichtels 2.8 amp driver as well?

  9. #9

    Default Re: DW 9a sst90 driver for automotive use....

    Quote Originally Posted by DKlaser View Post
    I see your diagram in the link. Is that how I would use these parts? Is there a more basic diagram that has everything clearly listed and what is what?
    I'm not sure if I can make it more "basic" than it is now. You just connect the components as shown and described in that link.

    Quote Originally Posted by LED4LYF View Post
    Sorry to jack your thread. I will be using xml led for an automobile application, I was wondering would the filter work with Der Wichtels 2.8 amp driver as well?
    Yes, same here

  10. #10

    Default Re: DW 9a sst90 driver for automotive use....

    Ok so if I understand the drawing correctly I would put these components accross the + and - voltages coming into the driver? That is not going to short anything out?

  11. #11
    Flashaholic* AnAppleSnail's Avatar
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    Default Re: DW 9a sst90 driver for automotive use....

    Quote Originally Posted by DKlaser View Post
    Ok so if I understand the drawing correctly I would put these components accross the + and - voltages coming into the driver? That is not going to short anything out?
    Capacitors pass no current with DC input, once charged. Diodes are one-way only, so don't get them backwards.
    My biggest light-hog is my camera.

  12. #12

    Default Re: DW 9a sst90 driver for automotive use....

    Ok, I ordered the parts, Thanks and I will let you know when they get here if I have any questions on the setup which I am sure I will....

  13. #13

    Default Re: DW 9a sst90 driver for automotive use....

    So the capacitors in your link are 220uf. In a different post you said to use at least 1mf worth of capacitors before the driver. So if I use five capacitors at 220uf that would make 1.1mf. Is that close enough, or can you not go over 1mf? Do I only need one zener diode before the caps? Once I have this little filter circuit soldered up I am guessing that it needs to be relitively close to the led driver, correct? One more question what guage of wire would you suggest for the incoming power to the filter circuit, filter circuit to led driver? Sorry for all the questions and thank you so much for all the help Der Wichtel.

  14. #14

    Default Re: DW 9a sst90 driver for automotive use....

    Yes 5 caps should be ok. It's at "least" 1mF so if you go over it, no problem.
    As for the Zener diode I would suggest to use something around 5 in parallel.

    The wires shouldn't be too thin and depend on current and length and how much voltage drop accross the wire is acceptable.

    you can predefine a acceptable voltage drop of let's say 1V across the wires.
    with 1 SST-90 at full power (35W) and 12V input voltage, the input current is around 3A. (35W/12V)

    With R = U/I = 1V/3A = 1/3Ohm. So the wire shouldn't have more than 0.33Ohm.

    Now let's say you need 4m of wire (2m for negative and 2m for positive).
    The electrical resistivity of copper is 1.68×10−8 Ohm*m

    The min. surface is A = resistivity* length/R = 1.68×10−8 Ohm*m * 4m/0.33Ohm = around 0.2mm˛
    now calc. the diameter ( if you don't know look at wikipedia) D = 0.5mm which is according to wikipedia AWG24

    Anything thicker than AWG24 is ok for the above example

    hope this helps

  15. #15

    Default Re: DW 9a sst90 driver for automotive use....

    Ok, I have all my parts here I ordered 10 of each part as I have 2 of these projects to do..... so let me get this straight on how I am going to set it up. The host for these projects are d size mags. I am going to drill for and attach a plug for the power to enter the maglite. I am then going to attach 5 of the zener diodes and 5 caps across the input voltage lines before the switch.... sound good?

    Also how do I know which way to point these zener diodes and do the caps care as far as what lead is soldered to + or - ?


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  17. #17
    Flashaholic* DIWdiver's Avatar
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    Default Re: DW 9a sst90 driver for automotive use....

    The zener diodes should have some kind of mark, a band or a line at one end to indicate 'cathode'. This end goes toward the + terminal. The caps will have more likely a "-" indicator, which goes to the negative terminal. They could have a "+" indicator, which would go to the "+" terminal.

    If you get these wrong, they will immediately fail when you apply power. If the fuse doesn't blow, the caps will probably explode violently after a few seconds to a minute. If you hear hissing or see one bulging, it's about to go!

    I might put the switch on the other side of the zeners, but I don't think it makes a huge difference.

    Don't be suprised by a noticable spark when you attach the capacitors. This is just the large charging current going into the caps. This will happen inside the switch every time you turn it on, which could be an argument for wiring the switch where you have it. Then the caps would charge only once when initially installed and wouldn't have that potentially damaging arc in the switch every time.

  18. #18

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    If it really makes a difference I can put the switch before the diodes and caps. Where should I put the fuse and what size should I use?

  19. #19

    Default Re: DW 9a sst90 driver for automotive use....

    The fuse should be placed before everything. The size depends on how many SST-90 you want to use.
    Each SST-90 draws around 35W. The current that goes through the wire is therefore approx. I = LEDs*35W / 12V
    So for a single LED a 5A fuse should be ok

  20. #20

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    DW, what do you think of placing the switch before the diodes and caps? This is all going into a D size maglite so the stock mag switch will be used. I can wire it either way so it really does not matter to me.

  21. #21

    Default Re: DW 9a sst90 driver for automotive use....

    I would place the switch before everything otherwise the capacitors become somewhat useless if it is between driver and capacitor.

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