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Thread: LED utility lighting. 24V. Noisy power supply

  1. #1

    Default LED utility lighting. 24V. Noisy power supply

    Hi guys

    Looking at some lighting for the engine room of my boat

    My first thought was to put a few star-mounted XP-G's or similar on some aluminium U section and then fill them with potting compound, preferably with enough in series that they can be direct driven. However this will get expensive quite quickly as I probably want 8 or 9 fittings in the various bits of engine room and may well be way over the top for brightness driving 9 of them in series per fitting.

    My next thought was to use the commonly sold LED "mood lighting" - but we're swinging on spanners and stuff not having candlelit dinners, and at something like 5w/m or 350 lum/m it does not seem intense enough. Also it is unclear how well it will tolerate the potentially noisy and variable power supply.

    I was wondering if you chaps had any good ideas or even something off the shelf.

    I can do machining, soldering, PCBs at a push, but have never done surface mount soldering or soldering LED chips directly for that matter.


    Design intents
    -withstand damp environment
    -similar light output to a 50-100w halogen
    -not too blinding to work near (diffuse light, not like a garden floodlight)
    -warm white colour with reasonable enough CRI to be comfortable to work with for wiring colours etc
    -work at system voltages from 20v (no problem if it's dimmer if the batteries are low) up to 30v (nominal charging voltage is around 29V)
    -withstand noisy power supply
    -each individual lamp independent, no centralised driver (don't want one fault to plunge whole engine room into darkness)
    -tough
    -expedient to build
    -economical

    Cheers!

  2. #2

    Default Re: LED utility lighting. 24V. Noisy power supply

    Found an existing model that looks ok but they're £400 each.
    (brightline 30W on ripca.com)

    Think I may build something along the same lines.

    A PAM2861 driver chip, driving 5x series warm white XPG2's.

    The 5x XPG2's already on stars seem to be about £6, the driver is about £6 and I'd need to get a small simple PCB made to take them.


    On the other hand, if I was getting a PCB made to take the things, why not get a PCB to directly reflow the LEDs onto. I wonder how hard/expensive it can be to get PCBs done Al backed or some other method to shift the heat?
    Last edited by yorkie_chris; 12-22-2018 at 02:55 PM.

  3. #3
    Moderator Alaric Darconville's Avatar
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    Default Re: LED utility lighting. 24V. Noisy power supply

    JW Speaker has some marine applications (looks like some random non-marine stuff) and worklights in 24V models, too.

  4. #4

    Default Re: LED utility lighting. 24V. Noisy power supply

    Quote Originally Posted by Alaric Darconville View Post
    JW Speaker has some marine applications (looks like some random non-marine stuff) and worklights in 24V models, too.
    Probably a bit rich for my blood from those guys. I'm thinking of fitting 8 or so lamps (less chance of ending up working in my own shadow) and the nearest thing I could find from JW Speaker was about £60 each.

    The application is on a boat but it is indoors so in this case anything with "marine" in the spec is just doubling the price for no good reason.

  5. #5

    Default Re: LED utility lighting. 24V. Noisy power supply

    Could you not get matched 12v sets of lights and wire them in series together on a 24v power system?
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  6. #6

    Default Re: LED utility lighting. 24V. Noisy power supply

    Quote Originally Posted by Lynx_Arc View Post
    Could you not get matched 12v sets of lights and wire them in series together on a 24v power system?
    Yup.

    Something like this could be a contender, wire 2x500mm lengths of it in series per fitting to get 15W@24V. Just doesn't say what the cut lengths of that are.
    https://www.ledhut.co.uk/led-strip-w...iABEgKnyfD_BwE

  7. #7

    Default Re: LED utility lighting. 24V. Noisy power supply

    -withstand damp environment

    Not too hard. You might try dielectric grease on all non-soldered wiring connections.


    -similar light output to a 50-100w halogen


    1,000 ~ 1,250 lumens per fixture?


    -not too blinding to work near (diffuse light, not like a garden floodlight)


    Easy.


    -warm white colour with reasonable enough CRI to be comfortable to work with for wiring colours etc

    Easy.


    -work at system voltages from 20v (no problem if it's dimmer if the batteries are low) up to 30v (nominal charging voltage is around 29V)


    This is the hard part. The diodes will burn right out if they get too many milliamps. You need something that will stand between the power supply and the bulbs and regulated the power for them.


    -each individual lamp independent, no centralised driver (don't want one fault to plunge whole engine room into darkness)

    At sea is no place for single points of failure. You could go with multiple drivers. I don't see how you could work with no drivers.


    -tough

    Easy.


    -expedient to build


    Depends what you can find.

    ************************************************** ***************

    You are starting out with a power supply that varies wildly from 20 ~ 30 volts. This clashes with the expedient requirement. Do you have any 12 volt batteries on this boat? Could you start out from one of them and run a 12 volt system? The battery itself would somewhat help shield you from fluctuations. 12 volt drivers and lights are a common item from the car, truck, and emergency lighting worlds.

    24 volt systems exist. You would want to find someone who sells stuff for solar powered lighting and see if they have a regulated power supply that will handle 24 ~ 30 volts on its supply side.

    Once you pick a voltage and have reliable power there are piles and piles of different lights available. I am partial to diffuse lighting (lights on a long string or something) because no matter where you stand you aren't blocking the light while you're trying to work, and you can't blind yourself if you look in the wrong direction.

    If you buy the cheapest, cheapest possible no name lights from some guy in China you might get OK quality, but you also might get some real short-life trash. Once you pick a voltage and a regulator, people here would probably have opinions on quality lights.

  8. #8

    Default Re: LED utility lighting. 24V. Noisy power supply

    how much "dirtier" is your power compared to a car? i used inexpensive (5-10 bucks each) dc dc converters of ebay in cars for various things, more times than i can count, none failed so far, no performance issue with devices, but my current was never higher than 3A.
    pm me if you want links to those converters, i wont post ithem here
    Last edited by alpg88; 03-14-2019 at 02:02 PM.

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