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User review: YINDING YD-2XU2 (Gemini Duo clone)

103K views 247 replies 65 participants last post by  garrybunk 
#1 · (Edited)
Nobody has written a review of this popular light so I'll do it :thumbsup:
Sorry for any possible errors or weird spelling - english is not my native language. Feel free to ask me any questions about this light, I'll try to answer them all.

https://www.fasttech.com/p/1443727
You can buy it here and on other websites. I'm writing a review of this custom version with XM-L2 neutral white leds:
Free shipping 1Set CREE XML2 T6 3B Bike Light 1600lm Waterproof Bicycle Light LED HeadLamp + 8.4v Battery Pack + Charger-in Bicycle Light from Sports & Entertainment on Aliexpress.com

«Lights reviews - Yinding 2xU2 (Gemini Duo Clone)» all pictures are available here, you can also view high-res originals (click on any picture, bottom-right corner will list all resolutions, use google translate if needed)

PACKAGING / CONTENTS
Cardboard "gift box", used for many chinese bike lights:

You'll get the light, battery, charger, headstrap mount, 2 rubber rings for handlebar mount and the box.

DESIGN

This light is a direct copy of Gemini Duo and probably the smallest 2 XML light that you can buy atm.
Gemini Duo ? 2013 Mtbr Lights Shootout | Mountain Bike Review
Gemini Duo 4 Cell front light - BikeRadar
Gemini Duo: Nine Brilliant, High-Powered Lights | Bicycling Magazine
You can read reviews of the original at the links above, most of the info there can be applied to this clone. Main differences between the original and the clone are much worse battery and 3 fixed brightness levels on clone vs 3 programmable levels on original.

Light's head is very small with 2 plastic TIR lenses over the leds. Weight of the head is only 59g, dimensions are 44x23x34mm without plastic mount.
There is a single button on the back with model name engraved near it.



Yinding compared to SolarStorm X2 and Fandyfire D99 (another simular light with TIR lenses, but a bit larger and heavier).


It has a magicshine-style connector, mount with piece of rubber glued on it (thats a sign of good quality light, cheaper lights don't use rubber there) and waterproof o-ring on the power cable.

You can also rotate the mount, another rare feature for chinese lights.
Mounting area is flat without any cable holes so you can use/make your own mount, see post #11 for example:
https://forums.mtbr.com/lights-nigh...xu2-gemini-duo-clone-887497.html#post10818765

BATTERY

Usual cheap chinese battery, 4x18650 2S2P cells in shrinkwrap, 7.4v voltage. Not waterproof! You have to cover it in plastic bags/rubber balloon/gloves or something to protect it from water or it'll short-circuit like this:

Battery capacity is kinda ok for chinese batteries but still horrible. I have 2 lights and here are the discharge graphs for them:

Battery 1, 3600mAh with very weird unstable voltage on discharge cycle.

Battery 2, 3200mAh with good stable voltage.
Both of these batteries will work for about 2 hours on high mode and imo you should replace them with something better from Xeccon/Magicshine/Gemini.

UI
4 modes, switched with single click in this sequence: off-low-mid-high-off and repeat. Strobe on hold, high frequency, not very usable imo.

TEARDOWN

Lets open it up and see how its made :thumbsup:
Starting from the mount:

3mm hex screw, plastic mount, 2 rubber o-rings between the screw, mount and the case.

O-rings removed. These o-rings will hold the mount at any angle so you can turn it and leave at specific angle that you need.
Nothing else on the bottom so lets move to the front.

2 small hex screws (about 1.5mm) hold the front part of the case. Removing the screws and front part gives us access to the 2 plastic TIR lenses and XM-L2 leds. Both lenses and the front part of the case have rubber o-rings under them so this light should be competely waterproof.

Leds are mounted on aluminium backplate and connected in series. You can also see that this specific version has XM-L2 leds (silver color of the led, 2 bounding wires instead of 3 on 1st gen) which the seller replaced himself...and it wasn't a very good job - there are fingerprints all over the plate and wires soldering is not very good.
Moving on, next we have to remove 2 screws on the sides of led's backplate:

These long screws are connected to the back side of the case.

With screws removed we can also lift up led's backplate to discover proper amount of good thermal paste underneath - everything is ok here. And here is an important part - led's backplate is mounted directly on the outer case, there is no additional pills here so thermal transfer is excellent (unlike D99 where leds were basically handing in air).

Moving on to the back, another view of the case inside and metal wall in the middle. There is a small hole in the center for led's wires and a hole on the side for power wire. Power wire doesn't have any pull-out protection so be careful with it.


2 pics of the driver and we're done. Soldering looks good everywhere, driver is marked "HX-1343". There are 2 smd leds for battery charge level indication, R110 current sense resistor that you can replace to increase current on leds (not recommended though, case can't really handle any additional heat).

ELECTRONICS

This time I'll use a picture with every measurement:


A few addional notes about it:
Current from battery is measured on external PSU set at 7.5v, thats the average voltage on discharge cycle. You can divide your battery capacity on current to get estimated runtime in hours (for the included battery at high mode its 3200/1700 = 1.88 hours, a good quality battery like Xeccon 5200mAh will give you 3.06 hours).
There are 2 values for current on leds because driver is a bit weird...it usually outputs 1.7A on high, BUT when input voltage is 6.9-7.2v it jumps to 2A. I have no idea why this is happening, but I double checked everything and it just works like this.
Driver will go out of regulation at 6.4v on input = leds will start to dim. This is a good feature as you'll notice that even if your light is mounted on helmet and you can't see the battery indicator on it. At about 5v it will turn off competely.
Lumens output is a very rough estimation (I don't have integrated sphere to properly measure lumens output) based on this calculator:
LEDCalc.fonarevka.ru
And with 20% reduction for losses in optics to calculate estimated OTF lumens. Still it should be close to real output, I verified that by calculating and comparing results for other lights/flashlights.

IMPORTANT NOTICE!
This light is very small and very lightweight so it will heat up VERY FAST. While moving it will be cooled by air so its not a problem, but don't run it on high mode for a long time when standing still - it can and will overheat very easily.
Some users have reported that it has overheat protection that will dim/turn off the light but I haven't tested that and I don't recommend to rely on such protections - overheating is bad for leds and electronics.
znomit said:
Tested the thermal cutoff today.
Cuts in around 70C (IR thermometer).
No hysteresis so theres a bit of flicker before it come fully on… guess thats a good visual warning. Cuts all modes back by half.

BEAM PROFILE

Compared to D99 on the right:

D99 uses the same type of lenses with wider angle (probably 22-30 degrees compared to 15 on Yinding) so the beam is almost the same. Its wider on D99 but its hard to notice on that picture.
Compared to SolarStorm X2 on the right:

Here you can see the difference between TIR lens and reflector. Reflectors on SSX2 have noticable sidespill and tight hotspot in the center while TIR on Yinding gives just one wide hotspot.
You can also see the difference in color temperature in both pictures. Neutral-white XM-L2 leds have more natural-looking slightly yellow color vs blue-white color of typical cheap chinese cool white XM-L leds.

BEAMSHOTS

2 simple beamshots on the ceiling:


This light uses TIR lenses (probably 15 degree wide like these ones 15 Degree Angle LED Optical Lens - Black - Free Shipping - DealExtreme) that give it a wide and floody hotspot with gradual fade at the edges, which is less tiring on the trail than usual high contrast reflector lights. Not a very good thrower though but should be an excellent light for the bars.
Its not a pure flood light and not a thrower, its somewhere in between and works great as a single light for low and medium speed riding on the roads/trails.
And a beamshot on the road, sorry for cellphone quality:

And here are some beamshots stolen from another threads and sites ;)
Nature Bicycle handlebar Bicycle Darkness Bicycle accessory





CONCLUSION

Pros:
Very small, very light.
Good mount.
Good wide-hotspot beam.
Excellent thermal transfer from leds to outer case.
XM-L2 neutral white leds in this version, better color rendition and easier on eyes compared to cool white.

Cons:
Bad batteries.
Overheats very easily.
No brightness levels adjustment like on original Gemini Duo.

Overall - great light imo, one of the best chinese lights atm. Not very powerful but so small and light! I will probably use it myself as a backup light for long rides, it doesn't take much space on the handlebars and provides good amount of light for forest/trails riding.
 
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#39 ·
Fixed one small error in electronics section, added beam profile to compare beam and color temperature.
Finally found a good dark place near my home so I'll start adding beamshots to my reviews. They will be made from cellphone so don't expect great quality...I can't carry my DSLR on my bike so thats the best that I can do right now.
 
#47 · (Edited)
A summary of where to get the yinding. I checked all of the following sites for this light:

fasttech
dx
wallbuys
aliexpress
kaidomain
lightmalls
ebay
amazon

They all had it except for kaidomain and lightmalls; ebay and amazon have it listed for much more $$ than the others ($60-70 range). It appears from reading all of these threads that only aliexpress has the upgraded xm-l2 version; the rest are are xml u2. Wallbuys has the lowest price ($43 w/coupon code). I can't find any true light-head only options; the ones that don't come with a battery are that way due to shipping issues. Anybody else want to add to this that has done some searching around?
 
#59 ·
Ok...Kir specifically mentions in the first post of this thread that he has a "custom" Yinding with the XM-L2 LEDs. The link shows this as being from Aliexpress (per bohcewar). He also linked one from Fasttech first, but this I believe just has the XM-L U2 LEDs (my mistake). Trd620, just click on Cat's link to go the XM-L2 light.
 
#63 ·
XML2 should be a tad brighter and a bit more efficient. I have the original Gemini Duo (XML U2) and it is bright and am currently running it as a bar light. Since I really like the size, quality and design of the Duo, I want to try the upgraded LED for my helmet.

For my use, this should be a perfect set up. My XML2 just shipped from Aliexpress, so I should have it shortly. Once I get it I will make some side by side comparisons in regards to brightness and run times..
 
#66 ·
thanks for that 127.0.0.1 will be placing an order tonight!

Just out of curiosity would any know if it is possible to install a remote switch from a battery pack to control the light levels or does it have to go to the light head? I went for a night ride on the weekend a remote switch would have been ideal to ensure the light head does not overheat
 
#70 ·
The aliexpress seller (Simon Mao) can replace the LED in the light with T5 5B1 or T6 4C at no charge - it least he did it for me (bought a total of 7 of these lights from him).

He is not a man of many words but he ships quick and he keeps his word (ordered several lights from him off Alieypress - just sent him money via PayPal - and got my items safe and sound).

Yes the soldering is sloppy (as seen in the first post - same was in my lights) but hey for those who don't know how to use a soldering iron it's a chance to get a Neutral White XML2 at no charge.

I guess you can ask to replace the led with whatever he's got in stock:
CREE XML2 LED - Shop Cheap CREE XML2 LED from China CREE XML2 LED Suppliers at Shenzhen Great Wall Technology Co., Ltd. on Aliexpress.com
 
#72 ·
Hi All,

Just got the XML2 version from aliexpress for $45, let's see how long it will take before it gets here.

So you guys mentioned the battery case/holder and charger is garbage?

Where can I get an alternate replacement?

Can I run this of a 2 cell battery (to save weight)?
My commute at night is only ~30 mins.

Do they make a case/holder for 2 cells?

Can someone school me on battery/packs?

Somewhere down the road I might get another one of this Yinding Clone for my helmet, can I connect 2 of these lights to a single 4 Cell Battery pack?

Thanks for all the info guys (just joined mtbr forum) and got into lighting.
 
#79 ·
I got my XML2 T6 3B version 18 days after ordering from Aliexpress. Paid 45 with the 30% off deal on the 2nd for the head only. It arrived in a plain brown box wrapped in a shipping bag and contained the light head, charger (no battery so not sure why they are sending a charger), head strap and orings with tabs. I was inspecting the light and noticed that the front plate was a little loose so I got my allen wrench to tight up the screws and discovered the threads were stripped as the screws just spun. I can pull the front plate off without touching the screws which is a little concerning. I have inquired with the seller about this. I ran the light and was pleased with the level spacing, the color and beam pattern. It's exactly what I was hoping for based on this review and other beam shots. I put it next to a small fan that would simulate a medium climbing speed with the indoor temp at 68F. Turned it on high and using my Flir thermal camera watched it climb quickly to 125F and then it slowly continued to climb up to 140F when I abandoned the test. It quickly dropped back down, probably 30-40 degrees in about a minute. The temp on the case is fairly evenly distributed with it slightly higher right next to the LED's. The front and back plates are not well connected, as would be expected with the orings, but does warm up. Overall, with the exception of the stripped screws, I am very pleased with the light.
 
#80 ·
I also got this same one from Aliexpress and my front plate screws are stripped also. I emailed them and they told me to " try and find" some screws that fit.. I also did not have the rubber gasket on the front plate.

Played Chinese light roulette and lost! Not surprised but this is a poor quality constructed light. Glad I have an original Gemini !
 
#83 ·
I don't know who is putting the t6 leds in, but yinding is specing U2. it is the second party who is shoving in the t6 led who is stripping the screws and leaving fingerprints and whatnot. if you want an unmolested and unstripped yinding, order u2 version
 
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