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  1. #1
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    quad led mr11 housing is this enough

    I have read that cutters are doing soon a quad mr11 lens and led kit.
    and wanted some opinions about this housing for the heat please.







    the diameter is 44mm the fins are 2.5mm thick seperated by 2.5 mm and as you can see go quite deep in to the aliminium .

    I think to use 4 leds I will need to use a maxflex which I think needs some heat sinking on its own so the fatter bit at the back is there for that purpose.

    I would like any ideas or feedback as to wether this is enough heat management for the quad when it arrives .

  2. #2
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    Couple of questions:

    How much does the housing weigh as it is in the pictures?

    I was reading the heatsinking post on here the other day and the interesting point was made that fins in line with the airflow would be significantly more efficient in disapating heat. This is obviously more difficult with 'turned' housings.

    Using the a new maxflex board with UIB2 installed there is nothing to worry about anyway, if it gets a 'bit warm' it will turn down untill its cool enough again.

    Heatsinking the maxflex neatly is the trick, how are you going to do that?

    I reckon that a mtb light cools extremely well when its moving so as long as all the heat sources are reasonably well 'thermally' connected to the outside housing you can get away with a lot.

    Yours looks at first glance like it will cope just fine.

    The lure of the 4 led kit is going to be strong

  3. #3
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    in answer to your questions Iggs

    The wall thickness in the middle is 1mm and I have left the fat bit for the maxflex to fit with the end cap
    so it is as far away thermaly as poss from the leds . I can put some fins in the endcap area if needed that was one of my future questions here .
    i.e how much heat sinking does the maxflex need in this sort of use.

    the housing weighs on our kitchen scales between 75 and 125 gramms as seen in the photos..

    I to have been following all the postings here and on cpf and I only have a small lathe so round it has to be . riding here in the uk ambient temp is never high when it is dark
    and the 3 triple crees that I have made for me and mates never get even warm when out riding ,
    so I was hoping that with the extra mass and large cooling fins that this would be ok for the quad mr11 when it is released.

    I would much prefer a quad mr16 size but my raw materials are limited to 50mm diameter
    at the moment . untill I can beg , steal , or borrow some larger dia ali bar.

  4. #4
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    I've been thinking a lot about heat sinking maxflexes. At the end of the day you are going to have to thermally connect the maxflex to the led's one way or another as the housing is always going to be the thermal connection to ambient.

    My thoughts are that as long as the connections to both are good then heat is going to be dispersed and then all your problems are solved anyway

    There is a bit of a conflict of interests in the different info I read.

    1. in the Cree heat sink info it describes keeping the electronics as far away from the led's as possible to minimise heat transfer too them

    2. with the heat sensing cababilities of the UIB2 firmware its advantageous to have the driver boards close to the LED's to increase the accuracy of the temperature 'gauges'

    For a bike light I think keeping it close and having it step down if the temperature ramps up is a good thing. With the adjustable levels in the Taskled UI's there is the option to tune it down if it doesn't work.

    I love the fact your kitchen scales are as acurate as mine!!!!!! I have scales that have a similar level of error to our too. I can keep weighing things until I get an answer that I like!!

    The success of a design using high powered leds and a taskled board running UIB2 will be easy to prove. Fire it up on max, leave it still until it cooks and the firmwear forces a step down then start riding and see how long it takes for the driver to allow stepping up the power again. The time lag will be the measure of the efficiency imho

    I wish I had access to a machine shop :-(

    I think that MR11 is a good size for a mtb light, why go bigger, small and light is good

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