# Ituo XP2 vs. Gemini Duo



## alexdi (Jun 25, 2016)

I'm looking for what's likely to be a bar-mounted light for fast singletrack. Can't decide between these two. The only specific reason I see not to choose the Gemini is that it doesn't like hot weather. 

I'm experiencing a bit of research fatigue. Which would you pick?


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## indebt (Nov 8, 2009)

If you live in the real heat i think you have your answer. If not then it's subjective. The XP-2 does have better thermal so you can ride fairly slow with higher output without it dropping to 20% output like the Gemini does. If its as good a thermal as i have, it drops output in such small increments most of the time you wont even notice unless you stop riding. So you dont have to be as aware of your output as the Duo. 

Unlike the XP-2,,,, the Gemini is a proven product and has wireless remote. If riding in cooler temps and you chose the Duo, those are two positives the XP-2 cant match as of yet.


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## Dirt Road (Feb 6, 2016)

I don't own any Gemini products, but I have a wiz20 which I use for a bar light. I like the wireless remote of the Duo, it's surely the future of bike lighting, but for myself, I like the xp2. Cheap readily available optics ($1.99ea) customize it for throw or flood or both... A kickin battery pack with 3200ma panasonics and lastly a top button on the lighthead. Xp2


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## Cat-man-do (May 16, 2004)

I don't have an XP2 but I do own one of the ITUO Wiz1's and know that these are well made products. I do own a couple Gemini products including the new Duo. Yep the Duo gets quite warm really fast especially if you run the high mode for extended periods ( which I don't do ). I run the Duo on the helmet with spot/spot optics. I didn't like the standard optics. The Gemini "wireless remote" though is a super big plus and makes the Duo a lamp worth owning. 

If you're going to compare lamps with duel emitters you can't forget to include the Gloworm X2. The GW's handle heat very well and have a wired remote ( new models soon to be sold with wireless remote more than likely at some point ). GW's also offer a nicer mounting system but the ITUO lamps are being made compatible with the Gopro mounts, a big plus. 

If the lamp is for the bars then having a wireless remote is not a main issue. The current model of the XP2 doesn't come with a remote but the Gloworm X2 does ( wired ) so at the moment the GW wins the duel emitter shoot-out but only because of the remote. 

Of course if you are willing to pre-order and wait till the end of July the ITUO people will be releasing their XP3. The triple version will come with a removable remote and likely will make a super great bar or helmet lamp. Gloworm won't be too far behind as they are upgrading all of their lamps to "wireless" remotes. The XP3 right now is the deal of the moment. 

Anyway, Tigris is likely the only one right now that owns all of these lamps so I'm sure he'll kick in his opinion very shortly.


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## tigris99 (Aug 26, 2012)

I do have both (along with many other lights, not going to admit how many).

Duo I'm not a fan of compared to the xp2.

Duo has heat issues and it's thermal protection is a very dangerous level step down. Just out of no where you have very little light output until such time as the head cools back down.

Part of its heat issues is inefficient driver which creates access heat and less run time.

Some have been experiencing issues with the wireless remote.

The xp2 is better in literally every way:

Ituo xp2 and xp3 both come with Removable wired remote so no signal issues, but also have the on head button so you can use either option.

Active, real time (no other light I have seen has this) thermal management. So output is only slightly adjusted to maintain head temperature inside safe levels, but it senses it faster than any other design as it's not driver mounted. This translates to almost unnoticeable output level changes unless your at max output while moving slow/not moving for too long, but as soon as you move again, output immediately returns to normal. And it deals with heat A LOT better. 10x better IMO. Mainly because the driver is highly efficient.

Doesn't use the band style mounts, xp2 (as all but the Ituo wiz20) uses a GoPro style mount. Including the helmet mount. Basically a GoPro helmet mount on Velcro straps. Bar mount is a quick release GoPro mount.

Wide range of cheap but Hugh efficiency optics. I know gemini offers some variations not sure what all exactly. Ituo doesn't use proprietary optics, so about and options for properly.

Duo comes with at best a 5200mah pack. Ituo uses only Panasonic cells, packs are 6400mah.

The only light that can begin to rival the xp2 is the glowworm x2 which has proprietary optics and mounts at a fairly higher cost.

Im honestly not impressed with the duo at all. It's a good winter time light to be able to run at max output with the help of the custom finned mounts. Their Olympia is better than their duo but has a couple draw backs and for the money could by the Ituo xp3 which spanks the Olympia and runs right along side the XS.

Final bit. Ituo quality is equal with the best I have (Glowworm) and such. So what you get for the money IMHO is far better going with the XP2 than anything else. Only other light I would consider paying for (which I did buy) is glowworm x2 (and I bought an XS)

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## MRMOLE (May 31, 2011)

^^^^^^^^^^
That's why I got an XP2 (XP3 ordered also)! Glad you didn't sugarcoat the thermal issues with the new Duo. I haven't seen anyone in a warm climate review this light and yet the hot running/overheating thing is always brought up. Probably something duo owners will have to deal with no matter what climate they live in.

Took my XP2 on a blissfull 32 mi. single speed ride tonight. Only about 5 of those miles were single track but switched back and forth between 70% and 100% power in that section. Was still 98 when I got home @ 10:48 pm so all those single track miles were done at 100+ with no heat issues. Far better designed light than the Duo IMO.
Mole


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## alexdi (Jun 25, 2016)

Thanks for the summaries guys, I appreciate it. 

I nixed Gloworm because they don't appear to be price-competitive. Not at $230 for 1500 lumens. 

The major draw of the Gemini is the wireless remote. That seems like a killer feature for a helmet-mounted light. But then, I've never used a helmet light and would not expect to helmet-mount a rig with an external battery. I have a Cygolite Metro 550 that might be good for this purpose. (Or maybe I've got this backwards.) 

I'm also not likely to buy two sets of Gemini lights, so the ability to share a single remote isn't a major factor. And I live in the south. My last two rides were at 88 and 92 degrees with average speeds around 11 MPH. Perhaps that nixes the Gemini. 

Sounds like if I need a light now, the XP2 is it. If I can wait, the XP3. Do we know if the current pricing for both is of the 'perpetual promotion' sort? Or how Ituo bills for preorders?


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## Dirt Road (Feb 6, 2016)

I have an xp3 on preorder, $185 for full kit. Expected arrival is end of July. Seems when Ituo gets lights in stock, the price goes up a lil bit so I jumped on with a preorder. There's nothing cheap about my wiz20. It's an awesome commuter/mtn bike light. So I have little doubt of Ituo and their quality and $185 for a triple with 2300lm is a good buy imo. Another big plus is Ituo offers a neutral white emitter which is mandatory!!


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## indebt (Nov 8, 2009)

MRMOLE said:


> ^^^^^^^^^^
> That's why I got an XP2 (XP3 ordered also)! Glad you didn't sugarcoat the thermal issues with the new Duo. I haven't seen anyone in a warm climate review this light and yet the hot running/overheating thing is always brought up. Probably something duo owners will have to deal with no matter what climate they live in.
> 
> Took my XP2 on a blissfull 32 mi. single speed ride tonight. Only about 5 of those miles were single track but switched back and forth between 70% and 100% power in that section. Was still 98 when I got home @ 10:48 pm so all those single track miles were done at 100+ with no heat issues. Far better designed light than the Duo IMO.
> Mole


 I understand both you and tigris are really PRO XP2/Xp3 and i dont disagree as it seems like a very good product,, and you both are credible guys. But all of us Gemini owners are not dealing with heat issues. Yes i do ride in cooler temps as i've disclosed but i wouldn't call the temps Cat has described as cool temps and if i'm remembering correctly he wasn't having heat issues either. There were others too with no heat complaints. Yes thermal is bad so you have to be careful to not ride slow on high output to activate (common sense!!)

Just my 2 cents.

Also surprised the Xeccon Z-11 hasn't been brought up. Tig you were quite happy with this product after reviewing!!


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## tigris99 (Aug 26, 2012)

Your talking about the OLDER duo, I'm referring to the NEW ones which have more output. That extra output translates to increased heat generation. 

It's not a thermal problem, but the new ones run substantially hotter that the old ones. The problem is they heat up and step down easily compared to most lights and they thermal step down is dangerous as going from full to step down suddenly is not too far above the light just randomly shutting off.

Our opinions are based on the fact of performance of the lights side by side. Being the cost of the lights, every aspect of the xp2 is better than the duo (except the wireless remote) so you get a lot better light for the money.

And in my opinion one shouldn't have to "be careful not to travel at slow speeds" to avoid a light dropping from high to low mode. If i need to slow down for a section I should be able to leave the light on high knowing I'll need it right back at high after the section I slowed for.

I thought the z11 was cool at first. Was fun during the cold winter. As soon as temperatures went above freezing then it started stepping down all the time. You literally can't leave it on max for more than a couple minutes even at higher speeds, it steps down. I have touched mine in months because they had some serious update work to make that light usable during the summer. So far no changes. Definitely steer clear of those for now if you want more than 800 usable lumens.

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## indebt (Nov 8, 2009)

tigris99 said:


> Your talking about the OLDER duo, I'm referring to the NEW ones which have more output. That extra output translates to increased heat generation.
> 
> It's not a thermal problem, but the new ones run substantially hotter that the old ones. The problem is they heat up and step down easily compared to most lights and they thermal step down is dangerous as going from full to step down suddenly is not too far above the light just randomly shutting off.
> 
> ...


 Must have missed reading that in your follow up somewhere. Good to know as i won't recommend the Z-11.

Cat was testing the (new) Duo in 80degree temps and didn't have heat issues?? Maybe he rarely used the high output???


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## indebt (Nov 8, 2009)

I think with so much output been shoved into such small lampheads you guys hit the nail on the head with it been a must to have the most efficient drivers and thermal heat management. I do 100% agree that if Gemini doesnt jump on board their sales will likely plummet with more competition out there offering better internals.


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## tigris99 (Aug 26, 2012)

My testing was done at 75deg.

It's not a matter of heat problems if you rarely use high mode. But why should you be restricted? I only lower my modes for longer, slow climbs. Anything else I leave where I want it and done. 

And my huge complaint wasn't that it kept stepping down on me. It's that I KNOW it runs hot which means Id have to baby sit the thing on hot nights other wise I ran the really high risk of it stepping down and cause me to crash because I couldn't see.

Basically not worth the the risk. Gemini lights would be fine if it wasn't for that brutal step down. Till they fix that (and have more too offer for the price like better mounts and so on) I can't recommend the DUO over ANY light in this price range. But to the xp3 spanks the Olympia too (and I really like the Olympia) on every aspect except the wireless remote.

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## indebt (Nov 8, 2009)

If my Xera/Duo were my primary lights i may have had more complaints i guess. My over priced Lupines like the XP2/XP3 have incredible heat management. I can if i want run full output and based on my speed will determine my output. Higher speed=higher output. So yes i've been spoiled for years with great heat management. I will be helping a couple friends who want to start night riding in the fall get set up with helmet/bar lights, so i think i'm going to pick up four sets of the Ituo's. Cheers!!


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## MRMOLE (May 31, 2011)

indebt said:


> I understand both you and tigris are really PRO XP2/Xp3 and i dont disagree as it seems like a very good product,, and you both are credible guys. But all of us Gemini owners are not dealing with heat issues. Yes i do ride in cooler temps as i've disclosed but i wouldn't call the temps Cat has described as cool temps and if i'm remembering correctly he wasn't having heat issues either. There were others too with no heat complaints. *Yes thermal is bad so you have to be careful to not ride slow on high output to activate (common sense!!)
> *
> Just my 2 cents.
> 
> Also surprised the Xeccon Z-11 hasn't been brought up. Tig you were quite happy with this product after reviewing!!


That's what I meant when I wrote "Probably something Duo owners would have to deal with no matter what climate they live in"(sorry if I wasn't clear on that). Having to take steps to insure the light doesn't overheat is what I consider having to deal with the issue. Certainly possible to take steps to avoid step-down. Method I use on my older Duo is to adjust mode programming to only run @ 70-80% power + I have a "Vancbiker finned GoPro mount" (see pic.) for additional cooling. This whole thing would be a far smaller issue if the Duo didn't have such a "Hard" step-down (dropping power to 20% at speed could be very bad). I currently own 6 Gemini lights so I'm also "pro Gemini" for their good points (power output, reliability, value) but think they can do better with the thermal/hard step-down thing.









Now for my "pro Ituo" comments. I know run-time has been mentioned as one of the XP2 advantages but only brushed over lightly. Large difference because of better efficiency and larger battery capacity. I borrowed one of the Tigris charts to show this + note that power output is only equal for the first hour at which point the Gemini fades and the Ituo keeps running stronger and longer.









Mole


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## indebt (Nov 8, 2009)

I am anxious to pick up four sets (probably all XP2's) for friends once i have the green light. Maybe two XP3's but i know with our crappy Canadian $$ and shipping it will be pushing their budget. Of coarse i'll have to tinker with the new toys before handing them over,,,,,,, you know,,,, just to make sure everything is working alright.


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## MRMOLE (May 31, 2011)

indebt said:


> I am anxious to pick up four sets (probably all XP2's) for friends once i have the green light. Maybe two XP3's but i know with our crappy Canadian $$ and shipping it will be pushing their budget. Of coarse i'll have to tinker with the new toys before handing them over,,,,,,, you know,,,, just to make sure everything is working alright.


At the moment the XP3's are only $15 (US) more than the XP2's which should last till the 3's arrive at the US distributor. Super deal that I hope you can take advantage of. It'll be good to have another voice to review Ituo products. Tigris, Dirt Road and I are the only ones posting that own these lights and if you notice seem very happy with them (sorry, Cat too has a Wiz 1 or 2). We all like to help people get the best lights they can for the money so Ituo's (Gemini and Gloworm too) success is important to all of us as another choice when looking for quality/reasonably priced lights. Too many "Cheap Chinese" companies and buyers who's most important interest is price makes any new (and current) manufacturer of quality/reasonably priced lights a valuable asset.
Mole


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## tigris99 (Aug 26, 2012)

^ x2

Glowworm, gemini and Ituo are the ones I recommend out of my massive pile of lights. Cheap Chinese lights to me are a waste of time. I like tinkering but only so much you can do and if you night ride a lot it's higher risk. And though I used to think "oh I can buy 5 of these for the price of one brand name light" but having to inspect and fix things on each light to make sure their safe to use becomes annoying.

Gemini makes decent lights with only one major issue (poor thermal step down design) and the duo is too small to push as hard as they do with that design. Are good "bang for buck" lights.

Glowworm makes awesome lights, I paid for those fully myself to have them. But on top of the higher price it costs extra for neutral emitters (though I had plenty to install in mine).

Ituo comes into the picture and we get everything we "wish for" that can be done at a good price point while maintaining high quality and product support. So we end up with Glowworm quality and performance (and xp3 has a bit higher output than xs) at a gemini price point.

Ituo durability some say needs to be tested, but Cat and another user has had their wiz1 or wiz2 since last year and no complaints. I've had the Wiz20 since last fall and has been used far more than any other light I own. From 10deg in the snow on my fatty to 85deg summer nights. Paved and taking a beating riding my fat bike on the trails. Not even a glitch.

Glowworm was the only light I would trust to run as a single light alone (group ride) but Ituo has my faith as well. Even ended up doing it which I never do for trail riding. Group ride where a fellow rider had a cheap crap tri clone that failed on her. Gave her my xp2 I had on my bars so she could continue with us and rode the rest of the ride with just my xp3 on my lid.

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## Cat-man-do (May 16, 2004)

indebt said:


> Must have missed reading that in your follow up somewhere. Good to know as i won't recommend the Z-11.
> 
> *Cat was testing the (new) Duo in 80degree temps and didn't have heat issues?? Maybe he rarely used the high output???*


You would be correct. Everyone rides and uses lights differently. Some people want to set their lamps to max and just let it rip. As for me I believe in using only the amount of light that "I need" in order to see. If I'm poking along on a winding section of single track that has only <100ft of line-of-sight visibility I don't need full power from my lamps. On those sections I might run med/med ( bars/helmet ) or med/low depending on my relative speed and how far my line of sight actually is.

Of course like everyone else once I hit a downhill section I like to play with speed. Then I'll run med/high or high/high. Where I live these sections only take a minute or two to ride through. Doesn't matter what lamps I use... I use all lamps the same way. I only use the output I need. So far I've had no big problems with using the Duo on the lid but it does bother me that the lamps do seem to heat up real fast. On the other hand they also cool very fast so I can't help but wonder what makes the Gemini's get hot so fast.

Anyway, I take the reviews by others very seriously. I do ride on warm nights and so far I've not experienced step-downs. My main concern with the Gemini's would be how they would hold up on an extended section where it "Would be necessary" to run high for more than 20 minutes. The only place near me I might be able to test the Duo on high for more than 20 minutes at a speed greater than 10 mph would be on a rail trail. I could do this on the road too but then I'd be annoying on-coming traffic which I'm not gonna do. If I get a chance to test the Duo on an extended run I'll update my review. Besides, it would be nice to know that if I choose to use a Duo on the helmet and ride down the side of a mountain that somewhere in that half hour descent the lamp isn't going to step down. I figure if you're riding faster than 10mph the lamp simply shouldn't step-down. This weekend I might get a chance to test the high mode on the Duo more thoroughly. ( not in the mountains though ) ( Please note; I'm generally using the two cell on the helmet so _usually_ I don't like to waste battery power. When I do an extended test I'll bring an extra two cell along just in case I need it. )


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## indebt (Nov 8, 2009)

MRMOLE said:


> At the moment the XP3's are only $15 (US) more than the XP2's which should last till the 3's arrive at the US distributor. Super deal that I hope you can take advantage of. It'll be good to have another voice to review Ituo products. Tigris, Dirt Road and I are the only ones posting that own these lights and if you notice seem very happy with them (sorry, Cat too has a Wiz 1 or 2). We all like to help people get the best lights they can for the money so Ituo's (Gemini and Gloworm too) success is important to all of us as another choice when looking for quality/reasonably priced lights. Too many "Cheap Chinese" companies and buyers who's most important interest is price makes any new (and current) manufacturer of quality/reasonably priced lights a valuable asset.
> Mole


 I have to admit getting caught up in a little bias and still feel the Gemini are good value. That been said i'm not ignorant to accept when there is a new and better product to be had. I too truly just want to recommend to fellow (woman too) riders the best reliable products without braking the bank unless they have a huge budget.

I have a lot of respect for the main players here and their opinions, i have learned a lot over the years from you guys. I am excited to get my hands on these products but am really worried how i'm going to get them here as Canada post looks to be going on strike.:madman:

I havent promoted the Gloworm products much only because i cant stand the UI. Once that has been improved then yes it is a top contender but more $$.


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## tigris99 (Aug 26, 2012)

I figured cat is much more controlling of his lights that even I am. My trail conditions change quickly once the first big climbs are covered so I rarely turn down after that cause I'd be shifting light output levels more than I'm shifting gears. And this year has been some.of the hotest in record for us and the duo doesnt like me leaving it blasting unless I'm up to speed and keep it there. I have a lot of fast flow that's hard braking into some tight and twisty, short steeps I can mash over quick and then back to speed again, rinse and repeat.

The only time I was cautious was when I was running xp3 as my only light on record hot night on dense wooded trail. Running a 3500mah 2 cell that had to last over an hour so I was regulating it a lot more than I nornally would as I had to compensate for no bar light so running it at higher power on medium than normal.

It's definitely a personal style and use matter but this summer is not one lights like the duo are doing well with. South West, upper here in North Western Illinois and so on, country is cooking. If you have an option and night ride a lot. Go with something that's better at dealing with it. And even the older duos according to Mole did better but they have much lower output than the new ones. Too hard to push such a little light head when its this hot imho.

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## tigris99 (Aug 26, 2012)

tigris99 said:


> I figured cat is much more controlling of his lights that even I am. My trail conditions change quickly once the first big climbs are covered so I rarely turn down after that cause I'd be shifting light output levels more than I'm shifting gears. And this year has been some.of the hotest in record for us and the duo doesnt like me leaving it blasting unless I'm up to speed and keep it there. I have a lot of fast flow that's hard braking into some tight and twisty, short steeps I can mash over quick and then back to speed again, rinse and repeat.
> 
> The only time I was cautious was when I was running xp3 as my only light on record hot night on dense wooded trail. Running a 3500mah 2 cell that had to last over an hour so I was regulating it a lot more than I nornally would as I had to compensate for no bar light so running it at higher power on medium than normal.
> 
> ...


Hey I was hugely biased on night fighter (for cheap lights) and glowworm. Was drueling over glowworm for a while before I could finally afford them. Gemini lights I like except that step down pisses me off because its so harsh it's dangerous.

Glowworm UI is annoying till you get used to it. Took me a while to sort it out so I didn't enter programming mode while riding.

Same point is my "complaint" on Ituo is a thing with the UI. You have to press and hold, go through the hidden flash to turn off. Fine on the wiz20 and such. But the XP series that should be off then the hidden flash. When you want your light off on the trail, standing there for 5 seconds and holding it gets in the way of enjoying sites sometimes. But that's literally one of only 2 complaints. Other is I think the GoPro style mount was better served in this case as single part on the light versus the slide lock intro the GoPro adapter then to the GoPro mount on the bars or lid. That's just an annoyance though. Doesn't effect function or durability at all.

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## Cat-man-do (May 16, 2004)

tigris99 said:


> I figured cat is much more controlling of his lights that even I am....


That is likely true. Particularly when I'm running two lamps with two remotes. Still there are times when I too have to chose a setting and just let it be, especially if it's a trail I don't ride too often and the terrain is constantly changing. Usually when that's the case I'm running med/med. That translates over to 600 lm on the bars and 700-800 lumen on the lid as that is about how I have the lamps programmed. At those settings I'm good for almost anything save a super fast downhill.

Right now I'm trying to decide where to ride. 92°F at the moment. Should drop to 80° by the time the sun goes down. I have a place in mind where I can ride twenty minutes without stopping but I almost hate to do that. I like my little breaks here and there. I'll have to run a battery from my pack just to make sure the Duo gets all the amps it needs for a long run on high. If I do the ride I'm thinking about, at the end of the ride I have to climb a 0.2 mile short/steep paved hill to get back to my car. I hate that climb, granny gear all the way and it still kicks my butt. I'll let you know how it goes. I guess it looks like I get my butt kicked tonight. ( Duo will likely get it's butt kicked as well... )


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## Cat-man-do (May 16, 2004)

*When things go bad*

Continued from my last post;

I went out tonight with the intent to ride a particular trail loop. The opening trail of this loop was a trail I discovered earlier this year as it was listed on an app I have the uses OSMcycle. This particular trail branched off a main road and was otherwise hidden from view. It lead down to a part of the Patapsco St. Park trail system that I have ridden for years. This particular trail though I only knew about recently because of the app. I've only ridden it about three times and the nice thing about it was that not only did it give me a nice opening downhill run through a very thick forest area but it allowed me to do the ride in loop fashion without having to ride too much of the park trails more than once.

Sadly as I'm approaching the trail head in my car ( using my GPS app as a guide ) my jaw drops completely to the floor as I approach the exact spot where the trail ( supposedly ) drops off into the woods. Much to my utter dismay not only is the trail gone but the woods where the trail used to be is gone as well! ( insert "the Empire strikes back"/ "Darth Vader theme" here ) In it's place was a new road and a spanking new ( elite level ) housing development! I can't tell you all the expletives that came out of my mouth when I saw this. I was so mad I was literally foaming at the mouth with anger. I don't know how they built this so fast but they did. Last time I rode that trail had to be in the Spring. The whole thing just reminds my of a lyric from an old John Denver song, "...more people, more scars upon the land".

Anyway I decided to do a ride in another area. It was damn hot tonight, 80's and was also very humid. When I did the test with the Duo it didn't take long for the Duo to power-down once I started keeping it in high. The thing is I don't think it would of happened but I came to a trail juncture where I wasn't sure which way to go so I had to stop. When I stopped I had to get the phone out to consult the GPS map. While I sat there a couple minutes trying to figure it out the Duo dropped output. At that point I turned it off, thought about my options again, took the trail to the left and off I went. I turned the Duo back on to high as soon as I started to move and continued to finish the ride. Actually both the Duo and the Gloworm X2 ( bars ) got very hot but only the Duo dropped in output. Once I started moving again the Duo continued to work on high although it remained quite hot to the touch. After I finished my short downhill most of the ride back to the trail head I was moving at a steady pace but not very fast. Once again the trails were lined with high grass and just loaded with curves. Speed was not an option. Twenty minutes later I got back to the car. I figure it this way, as long as you don't stop and leave the lamp on high OR leave it on high while climbing a steep, it probably won't power down.

Bad karma continues to follow me lately. I also had a small accident on the first part of the ride tonight as I must of hit a rock with my crank arm and it knocked my foot off a pedal and the crank arm somehow must of spun around and clocked the inside of my ankle. Ouch! gave me a good size bruise but I continued on.,,,

Yep, Duo gets real hot if left on, particularly if you ride super slow or leave on when stopped. Of course if you are riding super slow or stopped you don't need full power. If you use only the amount of light that you need ( OR ) use the remote in a timely fashion you likely won't have too much problem ( unless you live somewhere hotter than where I live )

If I were Gemini I would consider making a small attachable heat sink ( with fins ) that would clamp onto the sides of the lamp and perhaps slide into some of the top grooves to add some additional thermal contact..If made from aluminum it wouldn't weigh much and would do a world of good in helping the lamp stay cool. I'd make one myself but I'm not Vanc.  ( edit: Option two; coat the lamp head with Zinc oxide. Likely that will solve the heat dissipation issue for the Duo )


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## Dirt Road (Feb 6, 2016)

That sux loosing a trail. The pedal hit hurts like heck. But at least your riding which is always good! I've kinda ignored the Gemini line of lights mainly due lack of nw emitters. How is the wireless remote? Any issues besides the big step down?


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## Cat-man-do (May 16, 2004)

Dirt Road said:


> That sux loosing a trail. The pedal hit hurts like heck. But at least your riding which is always good! I've kinda ignored the Gemini line of lights mainly due lack of nw emitters. How is the wireless remote? Any issues besides the big step down?


The wireless remotes I have ( both Duo and Olympia ) work fine. The only time I ever had an issue with the remotes was when I first got it and was setting it up. My theory is that at initial start up the the lamp needs to sync and sometimes this doesn't happen right away. I used both set-ups now at least a dozen times and the only problem I've had with the remote had to do with the mount not being properly stabilized. If the remote is not stabilized on the bars then sometimes the lamp will do strange things when changing modes. I've only had that happen a couple times and now that I know about it I make sure the remote doesn't tilt, rock, slide.. etc. when I'm setting up the remote on the bars.

Gemini at some point is suppose to switch over to NW when they finish selling off the old stock but you can order the Duo with NW emitters from Action LED with NW emitters, you just have to request them and pay a little extra ( $25 ).

I too don't like the thermal power-down issue but in my case I'll likely never have a problem with it because I always power down the lamps when climbing or when stopped. What I did last night was just for demonstration ( worst case scenario ) purposes.


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## whokilledJR (Sep 24, 2012)

MRMOLE said:


> ^^^^^^^^^^
> That's why I got an XP2 (XP3 ordered also)! Glad you didn't sugarcoat the thermal issues with the new Duo. I haven't seen anyone in a warm climate review this light and yet the hot running/overheating thing is always brought up. Probably something duo owners will have to deal with no matter what climate they live in.
> 
> Took my XP2 on a blissfull 32 mi. single speed ride tonight. Only about 5 of those miles were single track but switched back and forth between 70% and 100% power in that section. Was still 98 when I got home @ 10:48 pm so all those single track miles were done at 100+ with no heat issues. Far better designed light than the Duo IMO.
> Mole


Interesting, a lot of people knocking the duo for it's thermal heat/step down. I have one and I'm in hot tropical weather territory (South of Vietnam). whilst I've noticed the step down, it seems reasonable. When it steps down it still seems a tad brighter than medium mode, which would mean in excess of 1000l, certainly nothing like stepping down to 20%.


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## whokilledJR (Sep 24, 2012)

Cat-man-do said:


> The wireless remotes I have ( both Duo and Olympia ) work fine. The only time I ever had an issue with the remotes was when I first got it and was setting it up. My theory is that at initial start up the the lamp needs to sync and sometimes this doesn't happen right away. I used both set-ups now at least a dozen times and the only problem I've had with the remote had to do with the mount not being properly stabilized. If the remote is not stabilized on the bars then sometimes the lamp will do strange things when changing modes. I've only had that happen a couple times and now that I know about it I make sure the remote doesn't tilt, rock, slide.. etc. when I'm setting up the remote on the bars.
> 
> Gemini at some point is suppose to switch over to NW when they finish selling off the old stock but you can order the Duo with NW emitters from Action LED with NW emitters, you just have to request them and pay a little extra ( $25 ).
> 
> I too don't like the thermal power-down issue but in my case I'll likely never have a problem with it because I always power down the lamps when climbing or when stopped. What I did last night was just for demonstration ( worst case scenario ) purposes.


Pretty much been my experience, the duo wireless switch on my remote is working flawlessly now as well


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## tigris99 (Aug 26, 2012)

whokilledJR said:


> Interesting, a lot of people knocking the duo for it's thermal heat/step down. I have one and I'm in hot tropical weather territory (South of Vietnam). whilst I've noticed the step down, it seems reasonable. When it steps down it still seems a tad brighter than medium mode, which would mean in excess of 1000l, certainly nothing like stepping down to 20%.


The new duo here in the states is no that bright at all. I've measured it and its no where near 50% output. The older ones aren't as bad from what I understand.

Sent from my XT1565 using Tapatalk


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## indebt (Nov 8, 2009)

I've been exchanging emails with Chris from Gemini this morning regarding improvements to Gemini's thermal accross their product line. Sounds like he's open to these improvements. Three examples he gave me were

1 Have thermal drop to 40% instead 20%

2 Have thermal drop down and up in 10% increments.

3 Have a very gradual step down and up.

IMO #2 or #3 would be a huge improvement.

I'll keep you posted.


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## tigris99 (Aug 26, 2012)

Wonder what happened to the other gemini rep that was supposed to be handling Mtbr. He's not been around in months.

Sent from my XT1565 using Tapatalk


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## indebt (Nov 8, 2009)

Yeah no idea where that rep has been. Also neutral tint lights are now in production and Chris was saying they look to release them in September when the night riding season really kicks in.

I had mentioned to Chris as well about an optional heat sync for the Duo (like Lupine has for their Piko) This would be a nice option for those riding in hotter areas. No word yet as to whether this will be looked at.


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## tigris99 (Aug 26, 2012)

Gonna need a good heat sink on the new one, it runs a lot hotter than the old ones.

Imho 1500lumens from a light that small is pushing it. OK for cooler climates but if it's over 80f at night, over heating is going to always be an issue.

Sent from my XT1565 using Tapatalk


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## indebt (Nov 8, 2009)

I agree. Not sure why these company's don't just add 20 extra grams worth of material to the lamp heads maxing out as many cooling fins as possible. IMO anything under 100 grams would be just fine on the lid. Or at least offer a heat sync for those customers who need that. Not to mention,,,,, it's an upsale of an extra $20 or so.


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## Dirt Road (Feb 6, 2016)

Wireless remote for the lid does sound like a win. Nw emitters forthcoming is good news.


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## Cat-man-do (May 16, 2004)

whokilledJR said:


> Interesting, a lot of people knocking the duo for it's thermal heat/step down. I have one and I'm in hot tropical weather territory (South of Vietnam). whilst I've noticed the step down, it seems reasonable. When it steps down it still seems a tad brighter than medium mode, which would mean in excess of 1000l, certainly nothing like stepping down to 20%.


The one I have stepped down to low ( ~20% ). Actually I have no issues with how it steps down. I don't think I'd like a gradual step-down. As long as the lamp output doesn't drop off while I'm moving at a decent speed I'm fine. I power down manually when I go slower anyway. I'd rather the lamp NOT drop in increments because then I might get confused when I start changing modes. At least when the lamp is powered down or turned off the lamp cools quite rapidly. When mine dropped I had it back and running on full power in less than a minute. I can live with that.

On the other hand I very much would like to see someone market an attachable heat sink. A proprietary model would be great if Gemini decided to make one but if someone else designed one to work with all small two emitter lamps that would be cool too. At least we have the Vanc Gopro mounts with fins for those who wish to go that route. Likely I'll be placing an order for one of those myself very soon.


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## Vancbiker (May 25, 2005)

indebt said:


> ......Not sure why these company's don't just add 20 extra grams worth of material to the lamp heads maxing out as many cooling fins as possible.


Adding more fins adds complexity/time/ cost in manufacturing.



indebt said:


> ......Or at least offer a heat sync for those customers who need that. Not to mention,,,,, it's an upsale of an extra $20 or so.


I've got that covered. Heat sink includes GoPro mounting too .


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## indebt (Nov 8, 2009)

Vancbiker said:


> Adding more fins adds complexity/time/ cost in manufacturing.
> 
> I've got that covered. Heat sink includes GoPro mounting too .


 You have been a saving grace with those heat sync mounts for many on this forum, other than your aftermarket one's the only company offering these as an accessory is Lupine.

Would cost really be as substantial as you say to make slightly larger lamp heads accommodating more cooling fins???


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## tigris99 (Aug 26, 2012)

That's where the bigger heads come in, Ituo and glowworm. Duo was aiming for feather weight but then push the output too high to have a true 1500. Combine that with a cheap Chinese grade efficiency for the drivers and you end up with heat issues. Not many companies understand how much driver efficiency plays a part in how a light deals with heat.

This is also why the glowworm xs may have more total surface area vs the xp2 (without a lot of work I can't say for sure but it's fairly close) but the xp2 will have better thermal performance because the driver is much more efficient. I have a graph in the xp2 thread showing how that plays out. More run time (on the exact same pack tested across all 3 lights) is the most noticeable difference. But less heat to deal with is an added bonus.

Sent from my XT1565 using Tapatalk


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## MRMOLE (May 31, 2011)

tigris99 said:


> That's where the bigger heads come in, Ituo and glowworm. Duo was aiming for feather weight but then push the output too high to have a true 1500. Combine that with a cheap Chinese grade efficiency for the drivers and you end up with heat issues. Not many companies understand how much driver efficiency plays a part in how a light deals with heat.
> 
> This is also why the glowworm xs may have more total surface area vs the xp2 (without a lot of work I can't say for sure but it's fairly close) but the xp2 will have better thermal performance because the driver is much more efficient. I have a graph in the xp2 thread showing how that plays out. More run time (on the exact same pack tested across all 3 lights) is the most noticeable difference. But less heat to deal with is an added bonus.
> 
> Sent from my XT1565 using Tapatalk


Bingo! Bar has been raised by Ituo with driver efficiency. All the other things being talked about here are good and necessary but are only band-aids to help the outdated Duo design compete with a newer better designed Ituo light unless Gemini finds a way to increase driver efficiency to a competitive level.
Mole


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## Vancbiker (May 25, 2005)

indebt said:


> ..... Would cost really be as substantial as you say to make slightly larger lamp heads accommodating more cooling fins???


When you are talking about a small light like the Duo it is. My current helmet light is close in size to the Duo and is ~60 grams (with wired remote). For its size and weight it has a huge fin area and it was very time consuming to machine. Several areas that are only 1mm thick. Pretty delicate and hard to hold while machining. Better cooling is achieved by orienting the fins parallel to the air flow too. Orienting the housing to cut them that direction would typically add another machining operation.


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## indebt (Nov 8, 2009)

Vancbiker said:


> When you are talking about a small light like the Duo it is. My current helmet light is close in size to the Duo and is ~60 grams (with wired remote). For its size and weight it has a huge fin area and it was very time consuming to machine. Several areas that are only 1mm thick. Pretty delicate and hard to hold while machining. Better cooling is achieved by orienting the fins parallel to the air flow too. Orienting the housing to cut them that direction would typically add another machining operation.


 I guess i'm having some difficulty understanding there been a big burden when Gemini is getting their lamp heads mass produced in China. One more step in a large production run i assume wouldn't be a big cost burden or time burden if the milling work is computerized,, if in fact that is how it's been done?? I do understand your position when doing everything manually.


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## Vancbiker (May 25, 2005)

The Chinese light housings are an near net extrusion that is CNC machined to create the fins and cavities. I CNC my stuff for the most part too. I do not have any idea how large of production runs Gemini does. For an order quantity of a few hundred housings, my CNC machine time to duplicate a Duo housing would be around 5-6 minutes each. Adding a machine stop to re-orient the workpiece and cut details in the new orientation would add maybe a minute. That's a 16-20% increase in machine time. More complex CNC machines or robotic parts handling could narrow that gap, but at a significant increase in the machinery cost.


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## indebt (Nov 8, 2009)

I'd like to see what you have done differently than the fining of a stock Duo, if i'm understanding correctly you have cut your fins front to back instead of left to right???

I guess the least expensive way for Gemini to improve the Duo's cooling would be to just add a little more mass, say bump it to around 90 grams with the fins machined the least expensive way and, or use a more efficient driver. Obviously Ituo has figured it out and kept cost down.


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## Vancbiker (May 25, 2005)

They are mostly top to bottom directly behind the LEDs. This post shows the housing from back.

New helmet light started - Page 3- Mtbr.com


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## indebt (Nov 8, 2009)

Those are some deep cuts (lots of cooling surface) it has to be really rewarding using something you made yourself!!


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## alexdi (Jun 25, 2016)

Thanks to your help and Keith at Ituo, I've just sprung for the XP3. 

My last ride with the Cygolite 550 was exhilarating. When you can't see anything past twenty feet, you have to react pretty quickly. Maybe not the right sort of adrenaline.


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## whokilledJR (Sep 24, 2012)

tigris99 said:


> The new duo here in the states is no that bright at all. I've measured it and its no where near 50% output. The older ones aren't as bad from what I understand.
> 
> Sent from my XT1565 using Tapatalk


The one I've got is from action led lights around 2 months ago. It steps down a tad on high however I can still cycle the modes, high still being slightly more than medium which indicates a moderate step-down. Perhaps they've updated the newer models. Shame I no longer have a lux meter to test it with.


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## indebt (Nov 8, 2009)

In email exchanges with Chris from Gemini just the other day, he acknowledged thermal steps output down to 20% output.


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## MRMOLE (May 31, 2011)

indebt said:


> In email exchanges with Chris from Gemini just the other day, he acknowledged thermal steps output down to 20% output.


Fixing that one thing would be a big improvement. First time my Yinding stepped down (50%) I remember thinking to myself "that's not too bad, wish Gemini would adjust their lights like this". I also remember the Yinding recovering quickly with temps. in the 90's so IMO Gemini's 20% is probably overkill. Glad to hear Gemini is interested in improving the thermal characteristics of their lights. Interested to see what they come up with.
Mole


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## indebt (Nov 8, 2009)

MRMOLE said:


> Fixing that one thing would be a big improvement. First time my Yinding stepped down (50%) I remember thinking to myself "that's not too bad, wish Gemini would adjust their lights like this". I also remember the Yinding recovering quickly with temps. in the 90's so IMO Gemini's 20% is probably overkill. Glad to hear Gemini is interested in improving the thermal characteristics of their lights. Interested to see what they come up with.
> Mole


 Yeah you know as long as company's are willing to listen to their customers and better yet keep tabs on the feedback on forums like this,they should do well provided they execute recommendations made by users of their products. Ituo is throwing down right now and this is good as it should hopefully keep the competition on their toes.


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## Skyraider59 (Jan 17, 2013)

I know my post will come to late for the writer of this thread, but I have been riding with the Ituo WIZ1/2 since September 2015 and later on with their WIZ20, they are used on my daily commute sun rain and snow as well as during our weekly single tracks rides here in the UK and the quality is very high. Back in December 2015, I bough an Gloworm XP2 1500lms as an early Christmas present and despite having spend a lot of money on that light I was delighted with its performance and design which were far superior to the cheap helmet lights I have been using (Solarstorm X2 and Yinding YD). Now after having used both the ITUO XP2 and the Gloworm X2,for me the Ituo XP2 has the edge by far on the design and price. 
Ituo XP2 is much better priced, has a removable remote switch + a body mounted switch, battery gauge is build into light (so you can use other battery packs and know how your battery is doing), gopro mounting, more sturdy helmet mount, proper bar mount, very effective thermal regulation, so far good quality and reliability. Here is a mini review video I have done, free music to fill the silent bits is not easy to find, so I hope you like it.


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## whokilledJR (Sep 24, 2012)

whokilledJR said:


> The one I've got is from action led lights around 2 months ago. It steps down a tad on high however I can still cycle the modes, high still being slightly more than medium which indicates a moderate step-down. Perhaps they've updated the newer models. Shame I no longer have a lux meter to test it with.


I should correct myself here for the record, my duo wasn't stepping down, rather I made the assumption as the difference between high and medium wasn't that noticeable. That being said I should have known better, human eyes aren't very good at perceiving light differences and the difference perceived between 1600l and 1000l isn't that much.

To confirm I live in a hot tropical climate and have never had the light step down, but that may also be due to the fact it's pretty flat where I am so I'm always moving at a decent pace. Out of interest I tried cycling around the block for around 5 mins at a low speed of 17km on high and it didn't step down. I would only imagine this light would step down if you're crawling up a step climb on high, and the question should be asked why you would be blazing 1600l at crawling speed.


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## tigris99 (Aug 26, 2012)

That's the thing, many riders just go max power and leave it instead of cycling modes. Duo does get up there in temps before stepping down at least. 

Sent from my XT1565 using Tapatalk


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## MRMOLE (May 31, 2011)

whokilledJR said:


> To confirm I live in a hot tropical climate and have never had the light step down, but that may also be due to the fact it's pretty flat where I am so I'm always moving at a *decent pace*. Out of interest I tried cycling around the block for around *5 mins* at a low speed of* 17km* on high and it didn't step down. I would only imagine this light would step down if you're crawling up a step climb on high, and the question should be asked why you would be blazing 1600l at crawling speed.


Curious what the approx. ambient temp. was when you did your test (important to have a point of reference). Also are your impressions based mostly on road riding? I know everyone rides in different conditions and have varied levels of fitness but I would consider 17km a "good pace" for trail riding not slow speed. If your light was cold when you started 5 min. is definitely not enough time to totally warm a light up if moving. I've done a lot of thermal testing on lights and virtually all the ones I've tested (with similar thermal threshold) require a minimum of 5 min. of runtime before their thermal protection is activated in 80F ambient temp. with no air-flow. Time to retest?
Mole


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## whokilledJR (Sep 24, 2012)

It was at the end of a ride so it had a lot of continuous use. It's really more cross bike territory where I'm at right now, mostly just light trails. Not sure on temperature, I'll check next time. I'm in the South of Vietnam right now to give you some idea. I'd assume the extra air flow from faster speeds would also somewhat be offset by higher temperatures. 

I don't doubt thermal protection would kick in after 5 minutes with no airflow, I certainly know how hot LEDS get from modding flashlights myself in the past.

My main point is I can't see the thermal protection of this light being a huge issue considering air flow and colder temperatures unless you're using it continuously and impractically on high. That being said going down to 20% is overkill.


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## MRMOLE (May 31, 2011)

whokilledJR said:


> That being said going down to 20% is overkill.


That's really the main problem with the Gemini lights (Duo happens to be the worst). While I've seen it mentioned before with the older models (what I own) Gemini's method of increasing the output to match the competition was to run the emitters harder (1.8a vs. 2.5a draw old vs. new) creating even more heat. For summer rides I would always run my lights no higher than 70-80% to deal with this but light testers are going to be more critical because of the fact that the Duo's main competition (X2/XP2) both have an easier to deal with linear step down, draw less amp's to make the same amount of light, and in the case of the XP2 handle my 100 degree ride temps. with no visually detectable loss of light output.
Mole


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## C.M.S (Aug 28, 2009)

For me the previous version of the Olympia was throwing fits when it came to step down (even @ 80 %)and Duo which is a previous version never had step down issues . I have since gone to a GW X2 and a 2016 Olympia and both have been fine . But like someone else said to me is that maybe i need to add thermal paste to my older Olympia and be fine . I want to try out Olympia/Olympia combo.


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