# how are gemini and lupine lights at overheating?



## rixsurfer (Jan 9, 2007)

Wondering how you Gemini and Lupine owners experiences have been with overheating in hot climates? In particular Gemini's Olympia and Xera and the Lupine's Betty, Wilma and Pico.

I'm in TX so sometimes it's still in the 90's at night. Currently I have a Magic Shine 870 and 808. When it's hot, the 808 seems to do fairly well but the 870 seems to overheat and power down often unless I'm moving at a fast pace. I'd like to upgrade to something where this isn't as much of a concern. The Gemini lights are attractive because of the price but heat dissipation and longevity are probably my first priority.

Thanks in advance for your responses.

Rix


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## juergenor (Mar 30, 2004)

Had a chance to try out my MS808e's and Piko 3 ( both at full power) earlier this year in hot AZ nights - no problems. They got hot but were able to handle the heat.


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## MRMOLE (May 31, 2011)

My Olympia and Xera lights have been trouble free so far in the Phoenix heat (100 + at night). When I trail ride I turn the lights down or off for anything other than a brief stops and while I never run the Oympia on high on the street, the Xera sits through traffic light cycles with no problems on high. These lights are also programable in 10% power steps,
so you can set them at a lower setting for the hotter nights if you want to.


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## AP783 (Aug 3, 2012)

good thread info


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## Justin Oughton (Jan 6, 2016)

I know this is an old thread, but have been searching for information about this. I have the Gemini Duo 1200 from mid 2014. I live in a fairly warm part of Australia (Northern New South Wales) and so I do most of my riding at night, usually for 3 hours on mixed bitumen, forestry roads and trails. For the last year, The Duo was my helmet light. I find that the overheating or the overheating set point (The temperature at which the light cuts out) to be unacceptable. It is an otherwise great light but some nights I can only run it at full power for 10 mins before it cuts down to 50%. It then takes about 5 minutes to cool down and fire up again. This is obviously worse the more up hill I do and the warmer the evening. 
I have just bitten the bullet and am going to try the new Lupine Piko 7. I was a little hesitant as the Piko has almost no cooling fins on the back and I dont expect there are too many hot days in Germany. It is also twice the price of the rivals (Gemini, Glowwworm, Tumble and Fall, and MTB-Batteries). Out of all of these, only the Lumen 2200 (MTB-B) makes reference to any kind of cooling technology (liquid cooled LEDs) but couldnt get enough info on them and there is no Australian distributor.


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## MRMOLE (May 31, 2011)

GoPro adapters for bike lights

Can't help with any Lupine information but this will help your current light run over 10° cooler. I can run my Duo in 100° ride temps with this mount.
Mole


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## tigris99 (Aug 26, 2012)

Heat is a price you pay for high output and small/light weight light. There is no way around it. Leds generate heat, drivers generate heat. Its a pick 2 situation: Output (lumens), size/weight, heat management. 



Only way to keep lumen output and be able to deal with high temps is larger (and of course heavier) light. To dissipate heat means more surface area. Since everyone demands small and light weight lights but has to have high output, the only option is thermal step down. Reduce power to leds to keep the system from overheating and damaging components.



This isn't a "bad design" or product fault, its the limits of current Led technology available that will fit the limitations and demands of cycling use. Some companies use driver components that are designed to run at higher temps, but those components cost alot more and also means the light head does what Mr. Mole refers to as becoming a "branding iron". Not desirable because you dont want a physical burn on your hands from touching your light. So what is available is what can be done currently.


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## indebt (Nov 8, 2009)

Justin Oughton said:


> I know this is an old thread, but have been searching for information about this. I have the Gemini Duo 1200 from mid 2014. I live in a fairly warm part of Australia (Northern New South Wales) and so I do most of my riding at night, usually for 3 hours on mixed bitumen, forestry roads and trails. For the last year, The Duo was my helmet light. I find that the overheating or the overheating set point (The temperature at which the light cuts out) to be unacceptable. It is an otherwise great light but some nights I can only run it at full power for 10 mins before it cuts down to 50%. It then takes about 5 minutes to cool down and fire up again. This is obviously worse the more up hill I do and the warmer the evening.
> I have just bitten the bullet and am going to try the new Lupine Piko 7. I was a little hesitant as the Piko has almost no cooling fins on the back and I dont expect there are too many hot days in Germany. It is also twice the price of the rivals (Gemini, Glowwworm, Tumble and Fall, and MTB-Batteries). Out of all of these, only the Lumen 2200 (MTB-B) makes reference to any kind of cooling technology (liquid cooled LEDs) but couldnt get enough info on them and there is no Australian distributor.


 If I'm reading your post correctly I'm getting the impression your climbing with the output on high? If so try climbing at 50% output and the problem should improve considerably. Only use full output once you have some speed and airflow.

If that's not the case, as MRMOLE linked,, that gopro heat sink adapter will fix the problem.

Also if you pulled the trigger on the Piko, this year Lupine has made a optional heatsink for it and I strongly recommend you order it. Between that and Lupines awesome thermal management you shouldn't have any issues unless you grunt out slow steep climbs on full power.


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## tigris99 (Aug 26, 2012)

Remember, top end thermal management is still thermal step down, just much less noticeable. It still cuts back power, but gradually instead of a huge step, then increases power as head cools. Same heat issue, just a more involved way of handling it so rider doesnt have to deal with a massive output decrease with no warning or having to manually turn the light back up to high.


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## indebt (Nov 8, 2009)

tigris99 said:


> Remember, top end thermal management is still thermal step down, just much less noticeable. It still cuts back power, but gradually instead of a huge step, then increases power as head cools. Same heat issue, just a more involved way of handling it so rider doesnt have to deal with a massive output decrease with no warning or having to manually turn the light back up to high.


 Yes, I am aware that it will step down but as you mentioned very gradual unlike the Duo, and with the optional heatsink should almost be unnoticeable unless grunting out long steep climbs on full power.


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## Action LED Lights (Nov 11, 2011)

The Gloworm lights also gradually step down power (in 2% increments) until the light stops heating. It's so gradual that you really don't notice it. Then when you start moving again the light steps back up to were it started.


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## TechniKal (Mar 18, 2004)

I had a Gemini Duo and switched to the Glowworm X2 and am much happier with the way the x2 handles heat. I don't want to futz with changing light levels all the time, and the terrain here doesn't really support that approach anyway. The change in brightness on the x2 is not noticeable where the duo switched from high to low, which is annoying.


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## patski (Dec 12, 2005)

Action LED Lights said:


> The Gloworm lights also gradually step down power (in 2% increments) until the light stops heating. It's so gradual that you really don't notice it. Then when you start moving again the light steps back up to were it started.


I was going to say that my Gloworm XS/X2 combo seems to handle hot Sacramento nights without a problem, but maybe I've never noticed the gradual step down, great design how ever they're doing it! :thumbsup:


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## arphaxhad (Apr 17, 2008)

MRMOLE said:


> View attachment 1040565
> 
> 
> GoPro adapters for bike lights
> ...


Didn't want a go pro mount on my helmet so I fashioned this heat sink.

Funny that my buddy and I both bought duo's and his drops down but mine hasn't yet on the same ride. I made this to keep it that way!

A little thermal paste on mating surfaces. So far in static tests the sink is as hot as the housing.
View attachment 1056976


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## gecco (Mar 15, 2016)

I also replaced the thermal paste , now it is much faster hot.
The Yinding is really small , a bit better having solved the Nitefighter BT21 .
She may be a little bit bigger but just behind the Led is the case back to the large cooling fins can dissipate heat better !
I both ( Yinding and Nitefighter BT21 ) provided with new thermal paste Arctic MX4 !

However, they are only in the state of hot or if they are operated with high light intensity , if you are traveling by bicycle they cool well
.

Otherwise you could even attach heatsink with cooling pads .

https://www.google.de/search?q=kühl...hUpG5oKHTJnALgQ_AUIBygC#tbm=isch&q=kühlkörper+


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## Vancbiker (May 25, 2005)

arphaxhad said:


> ......Funny that my buddy and I both bought duo's and his drops down but mine hasn't yet on the same ride.


You might want to look into that. The temp sensing on most lights is done by a thermistor, integral to the MCU chip on the driver board. If the driver board is not in good thermal contact with the light housing, the thermistor will not be able to sense the housing temperature.


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## arphaxhad (Apr 17, 2008)

Vancbiker said:


> You might want to look into that. The temp sensing on most lights is done by a thermistor, integral to the MCU chip on the driver board. If the driver board is not in good thermal contact with the light housing, the thermistor will not be able to sense the housing temperature.


Thanks! I will look into that. We got them both from Jim at ActionLed. He has always been awesome about fixing problems.

p.s. I appreciate you not critiquing my rudimentary machining skills. :eekster:

If you made one that still allowed me to use the stock o-ring mount, I would buy it. :thumbsup:


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