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Thread: USB powered LED & AC Adapter accepting USB input

  1. #1
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    Canton, Michigan, USA
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    USB powered LED & AC Adapter accepting USB input

    Greetings:

    Hi experts. Wondering if the low voltage LED light and adapter combo makes sense together and is safe? I've had the tandem in operation for several weeks now and I feel no discernible heat from the LED light source from the LED Light, nor the adapter. Welcome all opinions,




    • AC ADAPTER: is UL approved. Input details: 100-240V, 50/60HZ, Max 0.6A. Output details: 5.0V, -2.0A, Adapter accepts USB
    • USB LED LIGHT: 1W LED, Working Voltage: 5V DC



    Also introduced another more powerful LED light with the same adapter- Separate adapter, that is. Details follow:


    • USB LED LIGHT: 5V DC, 2.5W LED



    Thanks Folks,

    Mark

  2. #2
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    170704-2354 EDT

    From your profile you are a sales person, and from your post it appears you have no training in electrical circuits and their analysis.

    Apparently your power supply is a wide voltage range AC electrical input with, I am guessing, a somewhat regulated 5 V DC output with a maximum of 2 A output. Regulation is possibly reasonably good. Possibly +/-0.2 V relative to 5 V. The 2 A maximum output might be specmanship. Note 2 A at 5 V is 10 W. 10 W into an Ohmite 10 W resistor would burn your finger. But at this load there will be much less than 10 W loss in the power supply. At 10 W load you might not feel much temperature rise on the outside of your power supply. But you are not loading the supply that much, and therefore the power supply temperature rise would be less than at full rated load.

    A a seller you need to determine whether the power supply manufacturer produces high quality products, and how realistic are the specifications.

    When an LED is powered from a voltage source (your described power supply), then internal to the LED assembly there will be the LED itself and a current limiter.

    Some of the input energy to the LED assembly will be output as light energy, meaning radiated. The rest of the input energy is lost as heat, probably 75%. A 1 W resistor when dissipating 1 W will burn your finger.

    Neither of your lights should overload a power supply of your rating.

    Quality and honest specifications are your major concern.

    .

  3. #3
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    Are we to assume that this is a continuation of your "electrical box night light" thread? I thought that was all settled, a USB LED light was the way to go.

    http://forums.mikeholt.com/showthrea...t=#post1838642

    -Hal

  4. #4
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    Low Voltage

    Quote Originally Posted by hbiss View Post
    Are we to assume that this is a continuation of your "electrical box night light" thread? I thought that was all settled, a USB LED light was the way to go.

    http://forums.mikeholt.com/showthrea...t=#post1838642

    -Hal
    Hal:
    Bit of a crunchy comment there Hal.. No I assessed the replies in the previous thread and decided to actually select the adapter and low voltage lighting and like a responsible 'big boy' wanted to make sure the loads were safe. Thanks for your substantive input.

    Mark

  5. #5
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    Quote Originally Posted by gar View Post
    170704-2354 EDT

    From your profile you are a sales person, and from your post it appears you have no training in electrical circuits and their analysis.

    Apparently your power supply is a wide voltage range AC electrical input with, I am guessing, a somewhat regulated 5 V DC output with a maximum of 2 A output. Regulation is possibly reasonably good. Possibly +/-0.2 V relative to 5 V. The 2 A maximum output might be specmanship. Note 2 A at 5 V is 10 W. 10 W into an Ohmite 10 W resistor would burn your finger. But at this load there will be much less than 10 W loss in the power supply. At 10 W load you might not feel much temperature rise on the outside of your power supply. But you are not loading the supply that much, and therefore the power supply temperature rise would be less than at full rated load.

    A a seller you need to determine whether the power supply manufacturer produces high quality products, and how realistic are the specifications.

    When an LED is powered from a voltage source (your described power supply), then internal to the LED assembly there will be the LED itself and a current limiter.

    Some of the input energy to the LED assembly will be output as light energy, meaning radiated. The rest of the input energy is lost as heat, probably 75%. A 1 W resistor when dissipating 1 W will burn your finger.

    Neither of your lights should overload a power supply of your rating.

    Quality and honest specifications are your major concern.

    .

    Gar:
    Thanks for the load assessment. I am not a sales person but am in the manufacturing business. As you guessed I am totally out of my element with regard to electricity. Your reply is much appreciated! As you widely point out, Quality and honest specs. is my major concern as our supplies are in China.

    Best Regards,
    Mark

  6. #6
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    If that's all you wanted to know you will be fine. I really couldn't tell that from your post. Keep in mind that those kind of plug and play power supplies are protected against overload and no damage or fire will result as long as they are UL or NRTL listed.

    -Hal

  7. #7
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    My Supplier Specifics

    Quote Originally Posted by gar View Post
    170704-2354 EDT

    From your profile you are a sales person, and from your post it appears you have no training in electrical circuits and their analysis.

    Apparently your power supply is a wide voltage range AC electrical input with, I am guessing, a somewhat regulated 5 V DC output with a maximum of 2 A output. Regulation is possibly reasonably good. Possibly +/-0.2 V relative to 5 V. The 2 A maximum output might be specmanship. Note 2 A at 5 V is 10 W. 10 W into an Ohmite 10 W resistor would burn your finger. But at this load there will be much less than 10 W loss in the power supply. At 10 W load you might not feel much temperature rise on the outside of your power supply. But you are not loading the supply that much, and therefore the power supply temperature rise would be less than at full rated load.

    A a seller you need to determine whether the power supply manufacturer produces high quality products, and how realistic are the specifications.

    When an LED is powered from a voltage source (your described power supply), then internal to the LED assembly there will be the LED itself and a current limiter.

    Some of the input energy to the LED assembly will be output as light energy, meaning radiated. The rest of the input energy is lost as heat, probably 75%. A 1 W resistor when dissipating 1 W will burn your finger.

    Neither of your lights should overload a power supply of your rating.

    Quality and honest specifications are your major concern.

    .

    GAR:
    Attached are my supplier specifics. Any further thoughts on the mechanics of this set-up?

    Link 1: USB Power Adapter
    https://www.aliexpress.com/item/Fast...608.0.0.7j22V7

    Link 2: USB LED Light 2.5W
    https://www.aliexpress.com/item/New-...608.0.0.7j22V7

    Link 3: USB LED 1W
    https://www.aliexpress.com/item/1W-D...608.0.0.7j22V7

    Many thanks again for having a look,

    Mark
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  8. #8
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    Supplier in China and am hopeful of certification authenticity

    Quote Originally Posted by hbiss View Post
    If that's all you wanted to know you will be fine. I really couldn't tell that from your post. Keep in mind that those kind of plug and play power supplies are protected against overload and no damage or fire will result as long as they are UL or NRTL listed.

    -Hal
    Hal:
    Yeah I am a bit wary of the supplier source being in China. They show UL Cert. documents in the advertisement for the USB Power Adapter but I realize they can be falsified. Further the USB LED light sources have only CE,RoHS,CCC certifications (if they are actually certified).
    Sorry must not have been clear about my intent in my former post. Thanks for posting to this Hal.

    Best,
    Mark

  9. #9
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    Someone from here can tell you how to look up those listings to see if they are legitimate.

    -Hal

  10. #10
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    Location
    Ann Arbor, Michigan
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    170707-1059 EDT

    RomanyCaravan:

    I have never encountered the companies, and thus, no experience.

    If you plan to sell thousands of these units, then I would suggest you do some testing. You can only test a small sample, but it may tell you something.

    For the power supply:

    Apply minimum AC supply voltage (use a Variac for the supply), then with a variable load obtain data to plot output voltage vs load current from 0 to 150% of rated load current.

    Using a setup transformer from the Variac do the same test at the specified maximum input voltage.

    Report back on this data.



    For your LEDs measure current vs voltage for 4 V thru 7 V.

    Again report back.

    These simple tests may tell us what other tests to run.

    .

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