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[BK7231T] Cree A21 100W RGBCW bulb

etnguyen03 3036 11
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  • This is a short teardown of the Cree A21 100W tunable white + color changing bulb. It is sold in the USA and is currently $13 on Amazon, Lowes, and Walmart.

    The bulb uses a BK7231T Tuya chip.

    [BK7231T] Cree A21 100W RGBCW bulb[BK7231T] Cree A21 100W RGBCW bulb


    Opening the bulb: take a razor blade and insert it between the top plastic and the base. Then once you have a razor blade inserted, you can stick in a thin metal pry tool and carefully pry the top off.

    [BK7231T] Cree A21 100W RGBCW bulb


    Then, use the razor blade to pry off the bottom metal part, and then move the live wire out of the way.

    [BK7231T] Cree A21 100W RGBCW bulb


    Back to the top of the bulb now, the screws are useless -- don't bother removing them. You want to pry the entire board up and out of the housing. Once you do this, the board with the LEDs and the controller separates easily.

    [BK7231T] Cree A21 100W RGBCW bulb


    Installing OpenBK7231T: solder wires onto the 3v3, GND, TX1 and RX1; connect those to a UART and then follow the flashing instructions. You will need to hold a wire connecting CEN to GND to get the chip into flashing mode.

    The pin config is:

    * P7: PWM, channel 4
    * P8: PWM, channel 5
    * P9: PWM, channel 2
    * P24: PWM, channel 1
    * P26: PWM, channel 3

    (First post here, did I do anything wrong? Sorry if I did!)

    Cool? Ranking DIY
    About Author
    etnguyen03
    Level 2  
    Offline 
    etnguyen03 wrote 4 posts with rating 4. Been with us since 2022 year.
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  • #2 20303773
    p.kaczmarek2
    Moderator Smart Home  
    Thank you, it looks like a really bright bulb, but doesn't it have problems with overheating? And I think it obviously is not a real 100W, it's just marketing. Have you tried measuring the real power consumption?

    Also, would you be able to provide information which BK7231T module is inside?
    Helpful post? Buy me a coffee.
  • #3 20307306
    xpatryk89
    Level 9  
    p.kaczmarek2 wrote:
    Thank you, it looks like a very bright bulb, but is there any issues with overheating? And I think it's obviously not real 100W, it's just marketing. Have you tried measuring the actual power consumption?

    And would you be able to specify what BK7231T module is inside?

    100w is not it, dishonest bulb manufacturers do not give the actual power of the bulb, only the power of the traditional bulb which it is equivalent to. In other words, if a tungsten bulb is 100w and this one shines with a similar power and consumes 15w, they will write "100w" on the package. Some even use the term "100, 50 bulb" as equivalent to the power of light, so maybe it's more intuitive, although physically incorrect.
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  • #4 20307314
    p.kaczmarek2
    Moderator Smart Home  
    @xpatrik89 of course yes. That was a rhetorical question.
    I will add more - even if Chinese manufacturers give the "real" power of the "bulb", e.g. 12W, in practice it is often 9W or something.

    And yet another important thing is that the power does not translate 1:1 to the efficiency of lighting. There are more or less efficient light sources.
    Helpful post? Buy me a coffee.
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  • #5 20308047
    auditlog
    Level 10  
    xpatryk89 wrote:
    p.kaczmarek2 wrote:
    Thank you, it looks like a very bright bulb, but is there any issues with overheating? And I think it's obviously not real 100W, it's just marketing. Have you tried measuring the actual power consumption?

    And would you be able to specify what BK7231T module is inside?

    100w is not it, dishonest bulb manufacturers do not give the actual power of the bulb, only the power of the traditional bulb which it is equivalent to. In other words, if a tungsten bulb is 100w and this one shines with a similar power and consumes 15w, they will write "100w" on the package. Some even use the term "100, 50 bulb" as equivalent to the power of light, so maybe it's more intuitive, although physically incorrect.


    Well, here in the pictures - maybe not very intuitive, but it is stated that it is 15W and 1600lm -> for comparison, recently for ~ PLN 50 I bought a 15W from Osram (2500lm - I wanted a very strong light), the LED "bulb" had a term for efficiency class C (where most LEDs have an E / F specification and a luminous flux of 1500lm) - that is, these 15w and 1600lm are in total in the "Chinese" standard :)
  • #6 20309570
    ACCel
    Level 22  
    auditlog wrote:
    recently for ~ PLN 50 I bought 15W from Osram (2500lm - I wanted a very strong light)

    It's probably also a bit of marketing, 166lm / W in a boxed solution, taking into account the efficiency of the converter?
  • #7 20309579
    auditlog
    Level 10  
    ACCel wrote:
    auditlog wrote:
    recently for ~ PLN 50 I bought 15W from Osram (2500lm - I wanted a very strong light)

    It's probably also a bit of marketing, 166lm / W in a boxed solution, taking into account the efficiency of the converter?


    probably yes, but it shines (very) noticeably stronger than others with a similar power rating (~15W) - I don't have a light meter, and the assumption of very good room lighting has been implemented :)
  • #8 20312256
    etnguyen03
    Level 2  
    p.kaczmarek2 wrote:
    Thank you, it looks like a really bright bulb, but doesn't it have problems with overheating? And I think it obviously is not a real 100W, it's just marketing. Have you tried measuring the real power consumption?

    Also, would you be able to provide information which BK7231T module is inside?


    I have not measured the power consumption and I don't have the tools to do so. But the manufacturer claims that is a 100W equivalent bulb, uses 15W, and is a 1600 lumen bulb.

    It's a WB8P. More pictures:

    [BK7231T] Cree A21 100W RGBCW bulb [BK7231T] Cree A21 100W RGBCW bulb [BK7231T] Cree A21 100W RGBCW bulb [BK7231T] Cree A21 100W RGBCW bulb [BK7231T] Cree A21 100W RGBCW bulb


    [BK7231T] Cree A21 100W RGBCW bulb


    This one shows where to connect the wires.
  • #9 20312293
    p.kaczmarek2
    Moderator Smart Home  
    Thanks, I have added the extra information to the database.

    By the way, did the manufacturer "forget" to solder something here?
    [BK7231T] Cree A21 100W RGBCW bulb
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  • #10 21358205
    fierrote
    Level 2  
    I need some help figuring how to use openbeken. I used the tuya-cloudcutter to install the firmware. After adding the Wi-Fi credentials the bulb won't light up. I'm able to enter the config web and don't know where to start. I used the Tasmota Remota app to connect directly to th Cree bulb but can't turn it on. I tried googling but can't find a good guide. Trying to add to smartthings but only see it for home assistant. If you can guide where to start. Thanks. OpenBeken user interface with configuration and restart options for the device. Screenshot of the Tasmota Remota app displaying a device OpenBK7231T.
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  • #11 21358431
    p.kaczmarek2
    Moderator Smart Home  
    Welcome to forum, @fierrote . The lack of RGBW controls on your main panel strongly indicates that you haven't configured your bulb yet. Can you try doing template extraction as on our video?




    Alternatively, have you just tried to set manually the specified pins to PWM, as shown in the first post? It can be done via GUI in the Configure Module menu, under Config.
    Helpful post? Buy me a coffee.
  • #12 21360215
    fierrote
    Level 2  
    I went into the config and just pick my device from the drop list instead of input manually (because I'm lost) and it worked. Now figuring how to add it to HA. I install it in a QNAP NAS, but apparently you need the supervised version and could not find it on the NAS. I have N100 board on the way that I ordered and going to install it there. I really want to add it to smartthings but can't find much information. Thank you.

    edit: I just the first post and it has the pin layout, I didn't know what meant. I though it was the pin layout you needed to tap into to flash.
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Topic summary

The discussion revolves around the Cree A21 100W RGBCW bulb, which utilizes a BK7231T Tuya chip and is marketed as a 100W equivalent while consuming only 15W and producing 1600 lumens. Users express skepticism regarding the actual power consumption and brightness, suggesting that manufacturers often exaggerate specifications. Concerns about overheating and the accuracy of the claimed brightness are raised, with comparisons made to other LED bulbs. The teardown process of the bulb is detailed, including methods to open the casing and access the internal components. Additional insights into the efficiency and marketing practices of bulb manufacturers are also shared.
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