Good LED lights?

Discussion in 'My Favorite Mods, Tips, Tricks (and Blunders!)' started by drgiese, Aug 16, 2017.

  1. drgiese

    drgiese Active Member

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    I want to change my 921 style lights to LEDs. I bought these, which had mixed reports about brightness, but were cheap:
    https://www.amazon.com/gp/product/B07435MQ17/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

    But they don't work! I've flipped them around to account for polarity. A couple of them gave a dim flash when I popped them in at first, but they never fully lit.

    Can anyone either tell me what I'm doing wrong, or refer me to a good brand that will work? I need to replace 6 interior lights.
     
  2. tombiasi

    tombiasi Well-Known Member

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    Check the socket polarity with a meter.
     
  3. Snow

    Snow Well-Known Member

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    I bought cheap ones from China off Ebay and they have been working fine for 3 years.. Think total cost was around $10 USD for 12 lights...
     
    Marcia D Brainard and xxxapache like this.
  4. xxxapache

    xxxapache Well-Known Member

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    Same here
     
  5. xvz12

    xvz12 Well-Known Member

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  6. drgiese

    drgiese Active Member

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    If polarity is the problem, wouldn't flipping them around fix it? I tried that. Perhaps I got a bad batch of lights?
     
  7. drgiese

    drgiese Active Member

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    These don't look anything like mine. Here's a picture of my original bulb:
    upload_2017-8-16_20-49-41.jpeg
    Are they somehow interchangeable?
     
  8. tombiasi

    tombiasi Well-Known Member

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    Flipping would not necessarily reverse the polarity. Depends on the socket. The contact wire is only on one side each. When you flip it the polarity could stay the same. Measure it.
     
  9. Douggro

    Douggro Active Member

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  10. Douggro

    Douggro Active Member

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    Uhh.. errrr.. I'm not an electrical engineer by trade, but that statement makes no sense to me at all. Polarity of the socket is fixed; two poles, a Positive and a Ground. It cannot magically change polarity. Thus, if you are dealing with a polarity-specific device there are only two options:

    +++ / --- : socket with fixed polarity
    ========================
    --- / +++ : device, polarity reversed, device no work
    ========================
    +++ / --- : device, polarity match, device work
     
  11. JimmyM

    JimmyM Well-Known Member Gold Supporting Member

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    tombiasi is right. Some sockets will maintain their polarity if the bulb is flipped. I think it would be rare in a camper, but they do exist in automotive applications.
    Try re-bending the wires over to opposite sides of the plug base. See what happens. You may have just gotten a crap set of bulbs. It happens sometimes.

    Also, the bulb is a 921, but it has a T5 base. If you search for T5 base LED bulbs you'll have an easier time finding them.
     
  12. roybraddy

    roybraddy Well-Known Member

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    When I changed my interior lights for leds I used the cheap $4.99 CHINA EBAY LED Boards...
    [​IMG]

    These boards replace the 921 bulbs using the proper adapter leads. The first adapter lead in the above photo will plug into the interior ceiling light 921 socket.

    The backs on these board have double side tape to glue to the inside of the ceiling lamp like shown here...
    [​IMG]

    I did have to plug the adapter cord 921 bulb side to the correct rotation position to get the LED board to light up... I only got two boards on the first China EBAY buy and after it worked then I got the remaining boards I needed plus a couple of spares.

    These boards DO NOT have the regulator chips on the them which in my case would give off alot of RFI Radio Noise which would interfere with my HDTV reception especially when using my OTA Antenna and also might interfere with my NOAH Radio and ham radio operations. My POPUP trailer has three ceiling lights and have only lost a couple of three led lights in a roll out of the many small leds on the boards since installed in 2009. Still have my couple of spare boards in a bag... Well worth $4.99 each...

    Roy Ken
    [​IMG]
     
  13. Sneezer

    Sneezer Well-Known Member

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  14. JimmyM

    JimmyM Well-Known Member Gold Supporting Member

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    Regulated bulbs (12-28V rated) will last longer if you are plugged in a lot.
     
  15. arthuruscg

    arthuruscg Active Member

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    I replaced mine with the below plates. They come with both the bayonet and wedge plug adapters and are bright, even brighter then the porch light
    http://www.m4products.com/alplate-24-5630-ww-warm-white-double-aluminum-plate/

    I have the below wedge bulbs that I am going to try to add to my existing fixtures (with the plates) but connect to a 3 way switch so I can have a dimmer light at night time or swap them into the bunk fans.
    http://www.m4products.com/t10-5-5050-ww-warm-white-small-led-light-bulb-194-168-with-wedge-base/
     
  16. Douggro

    Douggro Active Member

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    Are not these equivalent statements?? o_O
    Color me confused as to how there is a way in a simple 12v two-wire two-pole circuit that ground and positive will suddenly reverse at the connector..
     
  17. JiffyPopJunkie

    JiffyPopJunkie Active Member

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    Going out on a limb here but are you getting a full 12V? I know some LEDs are really sensitive and wont work unless they get the volts they need as an incadesent will show some light even on a near dead battery
     
  18. roybraddy

    roybraddy Well-Known Member

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    In my case the 12V 921 sockets are fixed as far as 12VDC polarity is concerned. What I do here is install the LED first and if it doesn't light up I turn the LED fixture over and install it. The light assy get the other polarity when doing this...

    This would easy to accomplish using this type of LED Fixtures or adapter short cable...
    [​IMG] [​IMG]

    You will not be able to turn the adapter over 180 degrees using one of these style LED assemblies. The round enclosure with all of the working LEDs would be pointing up towards the light fixture instead of pointing down into the trailer...
    [​IMG]

    Another thought on the large round assembly is that the one shown above has a 12V regulator circuit in it and may cause RFI NOISE for your HDTV and other radio appliances including Ham Radio ops... Note the installed square chip... I would only order one to try out before dumping alot of money into it like I originally did and ended up giving them all away to my friends that didn't have any problem living with the RFI Noise problems...
    [​IMG]

    Just my thoughts here

    Roy Ken
    [​IMG]
     
  19. JimmyM

    JimmyM Well-Known Member Gold Supporting Member

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    Sorry. I should have said that the socket will maintain the polarity on the bulb. This is accomplished by having both + and - at each end of the bulb slot. So if you look at the slot it would be
    + -
    ------- < centerline of socket
    - +
    No matter what way you insert the bulb, depending on how the wires are bent at the base, it could be connected +/-, +/+, -/+, or -/-
     
  20. JimmyM

    JimmyM Well-Known Member Gold Supporting Member

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    That square chip is just a bridge rectifier to allow it to work regardless of polarity. It's not a regulator. A regulated LED will have a bridge rectifier, a PT4115 (tiny 5 pin ship), an inductor, and a capacitor.
     

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