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Discussion Starter · #1 ·
Just a little puzzle for you all ,but first the pictures and specs.

These are my lights ready for the winter they are not quite finished but near.







Quad cree R2 in each with the cutter optics 1 narrow and 1 wide
Bflex in each
both running at 1000mh
The bar mounts are connected to the lights with a bolt and artic silver epoxy to help
remove the heat to the bars .
battery is an 18 volt li ion makita 3000mah drill battery.
connectors are the Deans ultra simple and robust

OK now to the quiz.
the lights for this test are on the bike and in my garage with still air and ambient temp
about 16 c .

1/ Which light gets hot enough to trip the Bflex first.
the long thin one or the short fat one.

2/ Which light do you think looks the best

3/ would you buy one of these housings and what would you think is a fair price
that includes the bar clamp.
the housing is designed for the cutter kit s.
 

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Bandolero
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I may have an unfair advantage...

troutie-mtb said:
Just a little puzzle for you all ,but first the pictures and specs.

1/ Which light gets hot enough to trip the Bflex first.
the long thin one or the short fat one.
Short&Fat
troutie-mtb said:
2/ Which light do you think looks the best
Long&Thin
troutie-mtb said:
3/ would you buy one of these housings and what would you think is a fair price
that includes the bar clamp.
You make bar clamps too? Nice. I still like the Lumicycle.

I think you're in competition with Heatstroke for pricing. It looks like you've got an edge with the bar clamp but would probably take it in the shorts for shipping. I don't believe the UK Post does anything cheaply.
 

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I say the smaller 1 would stay cooler internally due to the increased ribbing increasing the surface area, but it's more about how well the LED's pass there heat to the outer body to allow the heat to dissipate into the air.

Find out soon I guess!!
 

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Difficult just by the pictures but apparently the thin one has more surface to dissipate the heat? I dunno the thickness though but I guess that the thin one would have better heat dissipation:confused:
 

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Discussion Starter · #5 ·
Hi Bruce
No I am not in competition with heatstroke he makes a neat light .
You would not believe how long it takes to machine a housing and clamp so it is just done for fun and the learning on the lathe, and if someone wants one then it is cool to have my housings across the globe usually for the cost of the aluminium + abit which helps buy more ali .

Ta for the opinion on question 2
 

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Discussion Starter · #7 ·
I will say for the purpose of this test that internally the lights are the same
in that the leds are the same distance from the Bflex that is a 12 mm thick heat sink and a 5 mm air gap from the back of the heatsink to the bflex.
the bflex is set to trip at 60 degrees
also both lights are nearly the same weight on my kitchen scales.:thumbsup:
 
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Short fat one gets hottest on the outside first, so trips the bFlex last... I hope 'cos thats the one I like the look of, at least from the front.
 

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I like the look of the longer one, and I think it might cool better, only because the finning is not directly over the handlebars so the convective airflow will be better, but I dont think there will be much in it, and both will be fine while riding. If I knew the surface area of the fins I might change my mind!
 

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Discussion Starter · #11 ·
StevelKnivel said:
I bet the long one trips the bFlex first...maybe...I like them both! Do the clamps get any of the heat to your handlebar?
Stevel Yes the clamps do get warm and so must take some heat to the bars
probably even more if I put some thermal paste under them .
but there is no need when riding even very slowly they remain cold.

The answer is

coming along soon:D
 

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No use with Carbon bars ofcourse, although if the clamps get warm thats better than nothing.

Wonders how hot my P7 Torch will get, atleast it's got a copperheat sink, I'll have to check this actually contacts the outter body and put some thermal paste between to improve the transfer to the body.
 

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I'm guessing the larger one takes longer to trip...

Although the fins appear to offer more surf. area on the smaller one, the increase in circumference by the larger size (and thus outer surface area) of the fatter one is probably more than enough to offset the difference in fins, plus it is more "exposed" to ambient, in still air, convection over the fins will result in eddies and "dead" spots that heat doesn't transfer to easily, compared to the outer body surface.
So I think the smaller one will trip first, but that's just a guess, a lot of variables of course.
 

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Discussion Starter · #14 ·
I gave you some bad info

I am sorry but I have given some wrong info in the first post.
The short fat light is using a Nflex not a Bflex.
The thin light is using the Bflex

The short fat one Trips out first in a time of 1min 35 secs
The thin one tripped in a time of 2min 45 secs

now there is something strange here because the fat one is noticeably cooler to touch
than the thin one when they trip.
 

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Its internal temperature which counts, ie the hotter the outter the more heat that is being transfered away from the LED's to the atmosphere.

Look at the contact inside from the Cree's Heatsink to the casing that'll solve that issue, I also bet, thinner case ='d more contact to the same size heatsink.
 

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Discussion Starter · #16 ·
Turveyd said:
Its internal temperature which counts, ie the hotter the outter the more heat that is being transfered away from the LED's to the atmosphere.

Look at the contact inside from the Cree's Heatsink to the casing that'll solve that issue, I also bet, thinner case ='d more contact to the same size heatsink.
The leds on there mcpcb are fixed to the heatsink in the lights , the light bodies and heatsink are all machined from one piece of ali so no problems with contact areas there.
 

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Is there a thin point between the heatsink and the outter body which would conduct less heat ???


I've wrecked 1 of my R2 ( hence P7 on order LOL ) The torch body felt slightly warm but the LED inside was too hot to touch after 5mins let alone after 40mins, something is stopping the heat conducting to the outside.

And with that short a run time i bet even with air flow on a warm night they'd both struggle to.
 
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dweeby said:
Short fat one gets hottest on the outside first, so trips the bFlex last... I hope 'cos thats the one I like the look of, at least from the front.
So I couldn't have been more wrong.
 

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troutie-mtb said:
I am sorry but I have given some wrong info in the first post.
The short fat light is using a Nflex not a Bflex.
The thin light is using the Bflex

The short fat one Trips out first in a time of 1min 35 secs
The thin one tripped in a time of 2min 45 secs

now there is something strange here because the fat one is noticeably cooler to touch
than the thin one when they trip.
I did somecalculation abut the mass (allen,1877) and using random but representative number I found out that the fatty should vae more surface to loose heat so there must be something between the LED and the aluminum transfer. And the more hot it becomes, the more heat transfer to the environment. Off course, depending on the thicknes of the aluminum I guess:confused:
 

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Discussion Starter · #20 ·
I think I figured it now



with the Nflex in the light

now with the Nflex pulled out also a comparison of the 2 lights



The Fat light tripped in 1min 45 with the driver pulled out of the case so no led heat could affect it.
so it seems that the Nflex creates more heat on board than the Bflex

also the housing was only just warm to touch

I have just upped the trip point on the Nflex to 70 degrees and done the side by side test
with the Nflex out of the light
the thin Bflex light tripped at 3 mins
the nflex was still going so I switched off
both housings felt about the same hotness IE touchable but becoming uncomfortable

What started as a bit of fun got larger than I thought it would but interesting to hear all the answers

Cheers BBW for the calcs and info interesting

anyway to sum up there is no problem with either light when on the bars and moving even very slowly

also am I right in thinking that because both lights heat up quickly that they are removing heat from the leds quickly as long as they can get rid of the heat to air as fast.
 
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