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SIX thousand and FIVE hundred lumens !!!!!!!!!!
http://reviews.mtbr.com/magicshine-l...2018-interbike
The beloved Magicshine brings us what we finally need in bike lights. Thanks to all the gods. 6500 lumens! I think you can have either 5000 or 1500 or all 6500 lumens. Thankfully now we will not only be able to blind everyone else on the road or trail, but we can now cause their eyeballs to burst into flames and maybe hopefully their heads will also explode. Yeah!!!!!! I don't know why "sms" did not report this in his post about Interbike. This has to be the most important thing to ever come from Interbike. He is letting us down. Here is the post from the article: "This latest offering from Magicshine incorporates everything they have learned about MTB lights over the years. The Monteer 6500 is MTB headlight designed for the most serious mountain biking enthusiasts, downhill racers and those who want nothing less than professional grade lighting system that can outshine the landing light on a passenger airliner. A max actual output of 6500 lumens is cranked out by 3x CREE XHP 50.2 and 2x XM-L2 LEDs. Like the Eagle series MTB headlights, Monteer 6500 is designed with multiple beam patterns modes, the XHP50.2 will put out a max of 5000 lumens of flood light, while the bottom row of XM-L2s shoots into the distance with up to 1500 lumens." It even has "CREE XHP and XM-L2 LEDs". So you know its got to be great. I bet it even meets or exceeds that German bicycle light standard. |
#2
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
On Mon, 1 Oct 2018 15:14:18 -0700 (PDT), "
wrote: http://reviews.mtbr.com/magicshine-l...2018-interbike A max actual output of 6500 lumens is cranked out by 3x CREE XHP 50.2 and 2x XM-L2 LEDs. Like the Eagle series MTB headlights, Monteer 6500 is designed with multiple beam patterns modes, the XHP50.2 will put out a max of 5000 lumens of flood light, while the bottom row of XM-L2s shoots into the distance with up to 1500 lumens." Only $350. https://magicshine.us/product/monteer-6500-mtb-headlight/ "Six cell battery pack uses super high capacity 18650 cells for a 10500 mAh total." Ok, let's do the math. Cree XHP 50.2 LED specs: https://www.cree.com/led-components/products/xlamp-leds-arrays/xlamp-xhp50-2 https://www.cree.com/led-components/media/documents/ds-XHP502.pdf The LED can be wired for either 6 or 12V. If I use an initial voltage of the cells at 3.85V, 3 cells = 11.6V, which is close to the maximum operating voltage and the end of the graph on Pg 8. At 11.6V, it draws 1.5 amps per LED and produces 180% of rated output (Pg 9) or: 1.8 * 1000 lumens @85C = 1800 lumens Three of these LED's will produce a total of 5,400 lumens. Close enough to the spec methinks. Cree XM-L2 LED specs: https://www.cree.com/led-components/products/xlamp-leds-discrete/xlamp-xm-l2 https://www.cree.com/led-components/media/documents/XLampXML2.pdf My guess(tm) is that these are running on one cell with a series current regulator. At 3.85V/cell, the current could be set to anywhere. So, doing this backwards, in order to produce 750 lumens per LED, each LED would need to draw: 750 / 280 = 268% of rated output From the graph on Pg 6, that requires 2.3 amps, which is getting a bit close to the absolute max of 3.0A/LED. Total drain for both XM-L2 LED's is 4.6 amps. Total current with all the LED's on is: 4.5A = 4.6A = 9.1 amps Total dissipation is: (11.6v * 4.5A) + (3.85v * 4.6A) = 71 watts Let's see how long it will run at full power. "Burn time ranges from 1.2H to 82H depending on modes" I'll assume the best 2200 ma-hr cells. That would be: 3.85v * 2.2amp-hrs * 6 cells = 50.8 watt-hrs which means the battery will last: 71 watts / 50.8 watt-hrs = 1.4 hrs That also works as advertised. The LED's can (probably) deliver the specified 6500 lumens total, but the 71 watts of heat produced by the LED's will need to be radiated or conducted somewhere. I don't see any cooling system on the package. Building it out of mostly aluminum doesn't work without some kind of air flow: "To maximize heat dissipating potential, light housing has been redesigned with hard anodized aluminum which covers almost the entire light body." Swell, no fins to increase surface area. Let's see what the package can do as a heat sink. Latent heat for aluminum is 0.900 Joules/gm-K. The light weighs 142 grams, which I'll assume is mostly aluminum. The light dissipates 71 watts with all the LED's turned on. I would guess that 75C would be uncomfortably warm for both the electronics and the bicycle rider. That's a temp rise of 50C (50K). Joules = Watts * seconds = 71 watts * seconds. Therefo 0.900 = 71 * seconds / (142 * 50) Time(sec) = 900 seconds = 15 min Not too horrible. One has 15 minutes of full brightness lighting, in still air, before the LED's burn your hand or cause a thermal shutdown. When there's air flow, there will be more cooling and therefore take longer to get hot. The dimensions are 72 * 42 * 44 mm. Surface area is roughly: (2 * (72*42/2)) + (2 * (42*44)) + (44 * 72) 3,000 + 3,700 + 3,200 = 9,900 mm^2 I'll finish this later as I need to do something else right now. In my never humble opinion, the specs are quite real, but I have my doubts about the ability the aluminum heat sink to remove the heat produced. It's going to get very hot running at full power. I bet it even meets or exceeds that German bicycle light standard. Probably true because StVZO only sets the minimum requirements. However if the spec has a maximum output, so as not to blind oncoming traffic, it would probably fail. There was a proposal to limit brigtness to 2.0 lux at 10 meters at eye level to reduce blinding oncoming drivers and riders, but I don't know if that was added. A bit of StVZO analysis: https://swhs.home.xs4all.nl/fiets/tests/verlichting_analyse/verkeersregels/de_stvzo/index_en.html -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#3
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
Jeff Liebermann wrote:
Ok, let's do the math. I put a flashlight to the handlebars the other day with re-openable cable ties. It seems to work OK, a pretty solid fix. I cut the cable ties with a combination plier so it looks neat as well. The flashlight is 3*AAA batteries with 9 diodes. How many lumens is that, do you think? I think I should get a proper bicycle light soon tho. -- underground experts united http://user.it.uu.se/~embe8573 |
#4
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
On 10/1/2018 10:18 PM, Emanuel Berg wrote:
Jeff Liebermann wrote: Ok, let's do the math. I put a flashlight to the handlebars the other day with re-openable cable ties. It seems to work OK, a pretty solid fix. I cut the cable ties with a combination plier so it looks neat as well. The flashlight is 3*AAA batteries with 9 diodes. How many lumens is that, do you think? I think I should get a proper bicycle light soon tho. One person who posts here spent years claiming that super-bright LED flashlights were better than bike headlights. Eventually, for Christmas I was given such a flashlight. It was bright enough that as I drove a freeway on a dark night, it clearly illuminated freeway signs overhead. But it was still a terrible bike headlight. You need more than brightness. You need proper optics, designed for the road. A circular beam cannot do that. -- - Frank Krygowski |
#5
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
On Mon, 1 Oct 2018 22:37:58 -0400, Frank Krygowski
wrote: On 10/1/2018 10:18 PM, Emanuel Berg wrote: Jeff Liebermann wrote: Ok, let's do the math. I put a flashlight to the handlebars the other day with re-openable cable ties. It seems to work OK, a pretty solid fix. I cut the cable ties with a combination plier so it looks neat as well. The flashlight is 3*AAA batteries with 9 diodes. How many lumens is that, do you think? I think I should get a proper bicycle light soon tho. One person who posts here spent years claiming that super-bright LED flashlights were better than bike headlights. Eventually, for Christmas I was given such a flashlight. It was bright enough that as I drove a freeway on a dark night, it clearly illuminated freeway signs overhead. But it was still a terrible bike headlight. You need more than brightness. You need proper optics, designed for the road. A circular beam cannot do that. Come now, a flashlight works perfectly well ... just ride slower :-) -- Cheers, John B. |
#6
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
On Tue, 02 Oct 2018 04:18:35 +0200, Emanuel Berg
wrote: Jeff Liebermann wrote: Ok, let's do the math. I put a flashlight to the handlebars the other day with re-openable cable ties. It seems to work OK, a pretty solid fix. I cut the cable ties with a combination plier so it looks neat as well. The flashlight is 3*AAA batteries with 9 diodes. How many lumens is that, do you think? Not enough info. Measure the current drain from the battery and I'll give you a good guess(tm). I just happen to have a similar flashlight handy, so I measured mine at about 160 ma. At 4.5V, that's 720 mw. Generic T1(3mm) white LED's typically have an efficacy of about 20 lumens/watt. So the output would be: 0.720 watts * 20 lumens/watt = 14 lumens I did a quick double check with my lux meter and measured 16 lumens. Here's how it's done: https://groups.google.com/d/msg/rec.bicycles.tech/UJdJQFTDgl8/NgOZUloVCwAJ I was going to turn it into a web page, but after the rather discouraging response I got from this newsgroup and two other forums, I decided I had better things to do. AAA Alkaline cells run about 900 ma-hr capacity, so at 720 ma, you get maybe 1.3 hrs of operation. I think I should get a proper bicycle light soon tho. Yep, good idea: http://www.learnbydestroying.com/jeffl/pics/bicycles/slides/bicycle-flashlight.html -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#7
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
Today I was once again in the accursed
hardware store, where I acquired a flashlight, with the following specification: FL 1 Standard (?) 18h 38lm 40m (range) 400cd (?) Unlike the other previously mentioned in the thread, which had 9 diodes and was suspected to shine at 16lm, this is considerably stronger at 38, with only one LED, while also using 3*AAA batteries. -- underground experts united http://user.it.uu.se/~embe8573 |
#8
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
FL 1 Standard (?)
18h 38lm 40m (range) 400cd (?) It didn't say the weight on the packaging. Anyway it is 105g including batteries. -- underground experts united http://user.it.uu.se/~embe8573 |
#9
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
FL 1 Standard (?)
18h 38lm 40m (range) 400cd (?) OK, so FL 1 is the "ANSI FL1 Standard" ("FL" is "flashlight", I take it) and cd is "candela". I suppose one has to read the article [1] to learn what sense to make of the 400cd specification. [1] http://www.led-resource.com/ansi-fl1-standard/ -- underground experts united http://user.it.uu.se/~embe8573 |
#10
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SIX thousand and FIVE hundred lumens !!!!!!!!!!
On 10/1/2018 7:18 PM, Emanuel Berg wrote:
Jeff Liebermann wrote: Ok, let's do the math. I put a flashlight to the handlebars the other day with re-openable cable ties. It seems to work OK, a pretty solid fix. I cut the cable ties with a combination plier so it looks neat as well. The flashlight is 3*AAA batteries with 9 diodes. How many lumens is that, do you think? I think I should get a proper bicycle light soon tho. The problem with 3AA batteries is that the run-time of a reasonably powered light would be very low. There are a few lights with 3AA batteries. but not many. By the time you buy rechargeable NiMH cells, a charger, a suitable light, you may as well buy a purpose-built bicycle light. I picked up a light at Interbike on the last day (when the exhibitors try to sell the booth demos so they don't have to ship them back). I actually didn't save much but I got it right away. https://www.aliexpress.com/item/GACIRON-professional-Bicycle-Light-Power-Bank-Waterproof-USB-Rechargeable-Bike-Light-Side-Warning-Flashlight-1600-Lumen/32802747811.html There are a couple of good features that I like. The "breathe mode" is a good daytime running light, lower power and not a strobe, but a modulated pattern. It can be used to charge a phone via the USB-A port. It is charged via MicroUSB. 1600 lumens is sufficient for road riding. I also have a dynamo light on the bike but it's not really sufficient for very dark paths. |
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