reduce 36v to 12v

Discussion in 'Electronics & Electrics' started by rickbishop, Dec 17, 2019.

  1. rickbishop

    rickbishop Member

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    The missus has a brainwave that she wanted an e-trike to go to work on, so after buying it and buying new batteries for it, she rode it and decided that she hated it. Fair enough, it's a bit hairy because unlike a normal bike, it follows the camber of the road, so you're always leaning to one side.

    The upshot of this is I'm fixing a few things before I sell it. The headlight that's on it is a shitty LED array, and honestly, more light shines out of my arsehole. At the moment, there's a resister on the positive wire which seems to be reducing the voltage from 36v to 32v.

    My googlefu is weak af, and honestly, all I can find is forumlas that I don't quite understand (I'm more electrical than electronic). So what should I get to reduce the voltage on this thing so I can put a decent LED in it? Cheap and easy is good, if you can link a jaycar product it would be even better!
     
  2. Symon

    Symon Castigat ridendo mores

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    What light are you looking at? Power consumption would help a lot.

    If it's possible you could put 3 x 12V LED's in series - don't need to convert anything then.
     
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  3. Hater

    Hater Member

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    buyers won't care how bright the headlight is, if it lights up, all good
     
  4. merlin13

    merlin13 Member

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    assuming you're not wanting to run ridiculous amps maybe take a stroll over evilBay/Aliexpress etc for suitable step-down supplies.

    Something like this perhaps. Cheap from O/S, obviously dearer here from an Oz supplier but quicker delivery if that's important.

    And two of them in series if you've overly paranoid about the input volts...
     
  5. FOTW

    FOTW Member

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    Just a question will those buck converters will thye automatically adjust the output voltage depending on the voltage required by the device ie if I connect 5v fan it will adjust the voltage automatically to 5v to match the fans required voltage?
     
    Last edited: Dec 17, 2019
  6. mtma

    mtma Member

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    No, you will have to set it up so the output voltage is as you desire.

    It's not sentient or anything to understand your thoughts or parameters of anything it's connected to.

    ED-

    As for the OP, you might be able to get a LED constant current controller that will accept 32-40 V. You can still use a 12V led string or COB unit, as long as the current is set correctly, because the voltage will be dropped by the constant current controller accordingly.

    However if you want to use a packaged LED unit intended to go straight to a 12V car supply you'll be best off to use the voltage converter as suggested previously.
     
    Last edited: Dec 17, 2019
  7. FOTW

    FOTW Member

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    Thanks never used and adjustable buck converter only fixed voltage ones. I assume the bright blue bit with the brass knob in lets you adjust the output voltage then.
     
  8. merlin13

    merlin13 Member

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    Yup. And a free PSA - be very aware those boards are often very unhappy afterwards if you connect them up backwards on the power input. Always Read The Fine Print on the evilBay ads for anything like that.

    And FYI, those particular bright blue blocks those ones are commonly called 10-Turn Potentiometers. Set up such on these boards they'll allow you to set the output between the minimum and the maximum nominal levels.

    As already noted, the Buyer probably wouldn't be that overly excited if you boost the photon output. It could/would/might be a selling point, but unless you wanted to go through the exercise of boosting the photon output for personal use before you sell it (and hang the expense...), personally you might be better off just getting one or two of the clamp-on LED lights and either remove them for other use later. Or leave them on to add to the sale price.
     
  9. OP
    OP
    rickbishop

    rickbishop Member

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    The current light is just a glow. For it to be actually useful at illuminating anything you would need to be on a remote outback road with dense cloud cover, and then you MIGHT be able to see the fog line.

    I dunno if I could be fucked any more. It now works, so that's better than it not working at least.
     
  10. merlin13

    merlin13 Member

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    30-ish volt LED array should be an retina hazard rather than dimmer than your arse - was it always like that? (the LED, not your arse...)

    Sounds suspiciously more like might be either a wiring/connector issue somewhere screwing up the available current, or the LED is actually borked.

    Either way, myeh. If you chose to get unfucked and get stuck for a new LED 'n power board, give us a nudge and I'll have a rat thru' the box of bits I've got over here.
     
  11. kombiman

    kombiman Dis-Member

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    ^this is the correct answer if you're not keeping it
     

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