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Thread: Startup Circuit and DC/DC for Conversion

              
   
   
  1. #1
    Senior Member SplinterOz's Avatar
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    Startup Circuit and DC/DC for Conversion

    I am finalizing some of my circuits and layouts.

    I am running a 72volt Kelly controller that does not require any input other than pack voltage. It does have a contactor driver but it is for 72volt contactor coils and I have a 12v coil model.

    So here is my simple diagram... not motor, throttle, bms etc shown... (will do other diagrams for the BMS and rest of the 12v wiring)

    TurnOn-Circuit.graffle.jpg

    The "Neutral" and "Run" items in the diagram are LEDs that are integrated in the Dash (I know I used the wrong symbol the program I have is limited).
    Let me know what you think and if I have stuffed anything up.
    Last edited by SplinterOz; 25 January 2012 at 2328. Reason: Fixed attachment size
    SplinterOz
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    http://rgelectric.wordpress.com/

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    Senior Member SplinterOz's Avatar
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    I also have one question... The Kelly controller has leads out to power "Running" and "Fault" leds and their circuit says "<2v" and "<5mA". I would like to drive two dash lights with these, especially the fault code, however the dash wiring is setup for 12v. Is there a micro relay or the like that would let me do that? Remembering that I have to keep them electrically isolated.
    SplinterOz
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  3. #3
    Seņor Member podolefsky's Avatar
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    Looks like there's something funny going on with the Run LED. It's going to end up connected to pack voltage, and also creates a connection from pack over to DC ground. So not 12V, and not isolated.

    The LED outputs from the Kelly are for running an LED without a current limiting resistor. The 12V LEDs will have a resistor in series. You might be able to run the LEDs from the Kelly if you remove the resistor. Or, does the Kelly also have a 12V output? My Curtis has 12V out for various accessories, and I use that for my Run LED.
    - Noah Podolefsky -
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    Senior Member SplinterOz's Avatar
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    You are right the run led is wrong. I will need another pole pair in the relay to switch that.

    Kelly don't provide a 12 volt output on the model I have. It does have 5 volt. The led I want to drive is part of a seal instrument cluster. I could run a separate led but I wanted to keep it neat.
    SplinterOz
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  5. #5
    Seņor Member podolefsky's Avatar
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    Quote Originally Posted by SplinterOz View Post
    You are right the run led is wrong. I will need another pole pair in the relay to switch that.

    Kelly don't provide a 12 volt output on the model I have. It does have 5 volt. The led I want to drive is part of a seal instrument cluster. I could run a separate led but I wanted to keep it neat.
    I'd say a separate relay to run the LED from 12V is the way to go. You could find a tiny one, it only needs to handle like 50 mA.

    I was thinking maybe you could open up the gauges and it might be simple to bypass the resistor on the LED. You have an Acewell, right? I have a Trailtech, and it's sealed, but it's not glued - I can take it apart.
    - Noah Podolefsky -
    The GSX-E

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    Senior Member SplinterOz's Avatar
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    Noah,

    Yes I am running the Acewell and I took another look today. The light arrangements (turn, neutral, warning, high beam etc) are in sealed and glued pods on either side. The wiring also shares the ground across all the lights. Internally they are LEDs but it looks like I will have to drive them like globes with 12 volts.

    As for the warning light from the Kelly could I use an optocoupler to do the job? The Kelly should be able to drive the LED in the coupler and then I can use it to switch the current to the warning indicator on the dash.

    As for the Run/Neutral and Controller turn on I can do that easily with a 3PDT Relay (or 4PDT if that is all I can get ) as that will allow my to do the normally closed for the Neutral and separate normally open for controller and the run light.

    New Diagram...

    TurnOn-Circuit.jpg
    SplinterOz
    From Australia'a Capital
    http://rgelectric.wordpress.com/

  7. #7
    Seņor Member podolefsky's Avatar
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    I see. Bummer, although I guess that will help the LEDs last.

    An octocoupler could do the job just fine. You could solder straight to the leads and pot it in epoxy.

    $PDT is probably what you're stuck with, they're usually just two DPDTs. The main issue will be finding one with a 12V coil that can handle pack voltage. I used a solid state relay for this, because it's hard to find a mechical relay that can handle over 28V DC.
    - Noah Podolefsky -
    The GSX-E

  8. #8
    Senior Member SplinterOz's Avatar
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    Noah, thanks for the advice. I can get an opto locally so I will try a test circuit. As for coil voltage you will notice all relays could are on the 12v side just one set of contacts have to switch pack voltage at low amps for the controller enable.
    SplinterOz
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    http://rgelectric.wordpress.com/

  9. #9
    Seņor Member podolefsky's Avatar
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    I see - controller enable should be OK since it low current and probably won't arc, but definitely check since it's high voltage. Worst that happens is you eventually burn out the relay contacts.
    - Noah Podolefsky -
    The GSX-E

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