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New Magicshine Lights on Eurobike

61K views 158 replies 28 participants last post by  pabcor 
#1 · (Edited)
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#126 ·
Got around to doing some beam shots comparing the MJ-902 to Yinding on a short ride with the dog tonight. Not very professional without tripod, but at least exposure and white balance were the same. Same battery (fresh from the charger) used for both light heads.

Single speed test setup
Bicycle frame Product Bicycle accessory Bicycles--Equipment and supplies Bicycle handlebar


Both lights on max. Yinding throwing both farther and wider
Nature Atmosphere Green Infrastructure Water resources


On the trail the difference is less pronounced. The MS lower levels are considerably lower (which may or may not be a good thing depending on personal preference)
Text Darkness Graphic design Graphics


More of the same
Darkness Symmetry Graphic design Graphics


Cheers
/Johan
 
#3 ·
Interesting. I don't think it's 8000 lumens. If it was it would draw about 24A. That would require quite a very large battery. 3500-4000 lumen might be doable though.

Monster of a heat sink on the back. Stupid that it's using an o-ring mount. As big as it is I would think a better mount be required. Looks like a smaller 4-up in the background. Could be there are smaller versions of the same design. If the UI and optic choices are right these could be interesting. ( none of that low beam /high beam stuff. All leds on or off at the same time. )

I find it interesting that Magicshine continues to market new products.
 
#4 ·
I agree with cat, no way that thing could handle 8 emitters at 3A each. 35-4k is more likely. Even at XP-L V6 emitters your talking ~2.8 per emitter. Head is just too damn small to handle that much heat. Plus the power requirements to pull it off even with a boost driver, battery would be huge or really short run time.
 
#7 ·
@pabcor: Sorry pab, I didn't open the link. I take back my previous comment. I figured 8K Lumen was just an estimate. Seems this is the actual claim from MagicShine. That is some kind of freaking awesome! Still, it must have one humongous battery to be able to provide that much output for 3hrs. Interestingly they didn't show the battery that powers this beast. Can't wait to see what kind of beam pattern it produces. Hopefully there will a smaller version that is more practical. I don't think I would ever need 8K Lm coming off the bars. 2K-3K...maybe. Actually, I like my current bar lights. A super bright lamp lightweight enough for the helmet would be nice to see though.
 
#8 ·
Hmm im have trouble accepting 8k lumens on a head that size, especially for 3 hrs run time. 600 lumens on 2 emitters is nothing, I have single emitter flashlights that push 8-900 and one that pushes 1300 (it gets HOT on full). I'll be waiting to see if it can push the lumens and if so for 3hrs without a 2lb battery pack :p
 
#12 ·
Ok now I am saying not possible, they are doing lumen rating more like the Chinese cheap crap.

Reason I say that is the claimed run times versus battery pack. So either their lying about run time, which I dont think is happening, or their rating their output based on emitter capability, not actual driver output to the emitters - loss at optics.
 
#14 ·
Funny math - MJ-900

2600mAh pack /2.6h runtime = 1A from the pack ie. 7.4W to the light. Counting some losses, 0.9*7.4W = 6.66W to the led. Divided by Vf 3.2V gives you about 2-2.1A. At that current you are going to get about 750lm out of U3 bined led. So take some losess because of lens and you are at 650lm out of the front. Of course this calculation is baseda on claimed runtime.

Based of calculation above MJ-902 should run leds even lower and you can expect about 1000lm out of the front.
 
#15 ·
2 Amps divided by 2, so one amp per led? I'm still confused on these calculations.

If I go to this chart:
Cree Product Characterization Tool
and select 2 leds, cree xm-l2 (white U3), 25 C junction temp and generate the chart.

if I go to
1 AMP - 1000 lumens - 6.05 W

if I scroll down to the 6.7 W line (to match your calculated wattage) I see the line
1.1 A - 1086 lumens - 6.7 W

I'm just trying to understand these calculations.
 
#16 ·
No, MJ-902 has 3.2h of runtime so it should run at lower current ie. less output. I've estimated it to 500lm OTF per led (based on specified runtime).

I understand you could be confused. There are several things to take into account including graphs and tables from Cree -> XM-L2 datasheet.
Particular graph you need to look is Forward current vs Forward voltage and Relative Flux vs. Current on page 5. Taken apropriate values from the graphs and tables you can calculate actual otput at different points. Keep in mind forward current and voltage are highly depended on each other. As current changes also voltage does (if not limited) and vice versa.
 
#18 ·
Yes probably you did edit it. 902 has 2 leds and 5200mAh battery which equals 2600mAh per led. So power from batteries per led it is the same as MJ-900.

But based on runtime MJ-900 is run harder. If you calculate it per led 2.6h on MJ-900 and 3.2h on MJ-902 (this is because it has doubled battery pack divided by 2 leds = 2600mah per 1 led = MJ-900). So MJ-902 has longer runtime per led which implies it is runt with less power = smaller current.

More close to the reality would be if you take 85degC junction temperature. At that point U3 would give you 800lm output powerd by 6.6W. I've estimated 750lm from the graphs. Not so accurate as the readings on the Cree page you have linked.
 
#19 ·
To make calculations easier, dont use watts, just use current. Vf is a constant in the fact its control by current and temps.

Then simple data sheets will give you output of the emitters.

Then take that total output and multiply that by .85 (85% due to 15% losses of optics/reflectors).

Wont obviously give u the exact number, only way to get exact numbers is a integrated sphere.
 
#20 ·
I don't know why I bothered to bring up the 902, I want to go back to talking about the 900. The 902 is confusing the issue in my mind as it comes with the rear light also.

You first stated that you can estimate that 6.66 W go to the leds (on the 900) and that would create 750 lumens before optics losses. Using the cree calculator with the settings I described and going down to the line which has 6.7 W in the third column.

1.1 A - 1086 lumens - 6.7 W

So I'm assuming that means 1.1 A to each led and a total of 1086 lumens.

I think that's pretty close to the 1200 lumens claimed by Magishine. You calculated about 750 lumens, which is a big difference to 1086 lumens, so how did you come up with that number?
 
#22 ·
Yes you are right and I'm an idiot! I thought the 900 was the same light head as the 902 without the rear light included. But it's only a single led light! Haha that's what I get for late night posting. I put 2 leds into the "led multiple", that's how I came up with 1086 lumens.

So basically the 900 is just a reworked 808 including a newer housing and a vastly overstated output. The only way it could be 1200 lumens is if they drastically overstated the battery life and it's drawing way more current (over 3 amps).

It's really kind of a dumb move by Magishine. They are vastly overstating the output and who is the target market for a single xm-l2 light? I don't think anyone is buying single emitter light for premium prices. The base model, or the new 808, should be the 902 lighthead without the rear light sold at the old 808 price.
 
#23 ·
Im with varider here, I see them way overstating lumens which is where the 8000 lumen claim is bogus on the big one. They are making claims based in max rated output, not driver output before lumen loss at least. They are slipping to typical cheap Chinese light ratings and charging a premium.
 
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