Maukka does your ROT66 measure higher @turn-on the hotter the head gets?
I’m getting 4500 when the light is really cold and 5000 when the head gets really hot.
Yes, I’m experiencing the same effect as you. Good catch!
When the light is cold and batteries are somewhat discharged (4.1 V during my test), I get a gradual increase in output of about +12% compared to 0 sec. When I turn off the light and let it cool for 30s and turn it on again it’s brighter still. 25% brighter than the initial turn on output, 11% brighter than it was at the highest during the first cycle. Third cycle is 5% brighter than the second at turn on. On the fourth one it wasn’t any higher anymore.
The initial output increase didn’t happen in my tests before when I used fully charged batteries, but I didn’t test the reset turbo method after the light had warmed up. I’ll test that later.
Can’t reproduce this with freshly charged and warm full batteries and a cool light. After the first 30 second warmup cycle and 30 second cool off period I get an increase of 3.4% in output. Subsequent 30/30 cycles didn’t go any higher than that but remained exactly the same until the light was starting to thermal throttle after the fifth cycle. I have significantly increased the thermal limit on this light.
So it probably has more to do with the batteries than the light. My test was done with 30Qs.
Being a FET driver it may be responding to the warmer batteries. I haven’t tried to measure this myself, but I’m always hearing that warmer cells deliver more power.
I wonder if Lexel saw this?
Explains the 5700 lumens I got the other day, though I can’t remember the voltage, cells or temps as I’ve slept since, I’ve not been able to match it yet.
I’ve just let the head cool to 20c and again I’m down to around 4500 lumens, I fire it on and off a few times on Turbo and it gradually goes back up to 5000 lumens. Same happens with both VTC6/VTC5A, Lumens stayed at approx 5000 when I swapped cells to a cooler set.
I’ll try it with my 30Q’s later.
(my Convoy S2+ alternates between 270 and 370 lumens with VTC5A and my D4S alternates between 4400 and 4600 with Shockli, probably for different reasons, I’ve only ever had lights throttle down from turn-off until recently.)
I just received my Fireflies that I ordered on the last day of the GB. I still haven’t received the one I ordered before the GB.
Here are the results measured with the TA Lumen Sphere calibrated with Maukka lights.
Champagne host 219B 4500k 9080
4650 lumens at 0s
1482 lumens at 30s
Dims at about 17s
Black host 219B 4500k 9080
4500 lumens at 0s
3991 lumens at 30s
Edit: The champagne host was tested with fresh off the charger VTC5D and the same cells were then used on the black host so that might have accounted for some of the lumen differences at 0s.
I tested the Champagne host twice and it steps down at about 17s. It doesn’t do that on the Black host. Anyone have any idea why that is?
The tint is super nice. It’s the best looking tint I have seen to date. I was afraid it might look too magenta as some people have commented on the 4500k 9080 but I’m so glad it is not magenta at all, just some pink/rosy. Even on turbo, it’s not as rosy looking as what you see in the pics. It’s very white at the center of the beam. On the lower modes, it is just neutral white and perfect.
I compared it with all of my other lights that looked neutral tinted before and now they look ugly yellow/green.
The calibration of the internal temperature sensor is probably rather inaccurate. If you want to compare them properly, configure the thermal stepdown for the same measured head surface temperature on both lights.
I’ve had mine step down at 20 odd seconds and 50 seconds from cold, it reads different at start up depending on temp/volt, strange light.
Maybe someone who knows more about the driver can shed some light for me: So the light has ruler flat regulation when in mode sets, but when in ramping is every single possible lumen output up to 700 lumens fully regulated as well? IE, is a hypothetical 537 lumens ruler flat regulated, is 284 ruler flat?
Yes. All the modes utilizing only the 7135 regs are flat in output.
Thanks! How does the light handle stepdown to the 700 lumen regulation if it’s getting slightly too hot at say like, 1000 or 1200 lumens? Is it a temperature controlled deal where it will eventually step down to 700 lumens 10-20 minutes in?
Assuming we are talking about the Nichia version, if the thermal limit is reached it will step down from 1000 or 1200 lumen down to 700 lumen (which is FET turned off and all the 7135 chips working at 100. Or channel 3 turned off and channels 1 and 2 working at 100)
Starting at higher lumen levels the light usually has to step down twice to get to this fully regulated level as seen in the run time chart below.
This is a complicated question and I’ve tried to answer it as simple as I can, but it still may not be clear. You can get some more information from this thread.
Ps. You can choose the temperature at which it steps down.
Received my ROT66 219B from GB.
The bad first.
The driver doesn’t seem to memorize nothing! If you re in Modes and do a power cycle (physically lock out or changing batteries) you re back to Ramping again. And if you want to change any setting (I tried many times to disable blinkys, to choose 6 mode from the mode set, and to set the thermal to timed spepdown) after the power cycle… back to default!!
The driver seems to reset to the default every time you do a power cycle. If you don’t do a power cycle everything works OK.
I always change these 3 settings in my narsilm flashlights, and i always physically lock out the lights every time, so for me this is a huge problem.
The second bad is that i think one of the leds looks like the dome has lifted from the phosphor or something like that, if i can described it correctly. I took some photos but i don’t know if you can see it. The led works OK, but if you see it directly with moonlight the damaged side looks more yellow. Maybe in the factory push hard the tir? I don’t know.
I will forward my comment to fireflie and see how it goes…
Now the good.
I have many lights with 219B sw45k R9080. This is from the best, more neutral, excellent tint and beam profile.
Fireflies have told me to fix mine or send it to Vinh.
It’s a huge gamble buying a ROT66.
i smell fishy about this light from the start…. lucky i didn’t jump on to buying one.
Mine is still en route to me but reading your post makes me worry already. How can they suggest their customers to resolder a defective LED by themselves? I'm pretty sure that most of their buyers are not skilled to do such a repair. How can they suggest you, living in England, to send the light to Vinh Ngyuen who lives in the US? In my humble opinion, this sounds rediculous. Will they gonna pay the significant shipping costs and the tariff fees for inbound/outbound customs. As far as I know, in Germany every single parcel from the US will be processed by customs and you always have to pay at least the 19% import turnover tax.
In my opinion, if they want to achieve and keep customer satisfaction they should quickly think it over again and send you a new light.
I don’t think fishy is the right word. They are a new company and this is their first light. The design needs some tweaking.
It’s a known issue, and happens randomly. Basically, if you keep trying, keep making it save settings, it should eventually remember. Make sure to save a few times before disconnecting power.
And if I understand correctly, it should be fixed in the next batch. Not that that helps you, but hopefully at least things will be better for others later.
This happened to me as well. After using the light and changing the settings for a while it started remembering the settings.
Please don't take this as an offense. I know about the risks of buying things that are brand-new but when the groupbuy started, I was not aware that the driver had a "known issue" and that the light would behave weird in terms of saving settings. I am wondering if a flashlight that cannot save its settings would be subject to a warranty claim and exchanged by a revised version from the next batch. I have never seen a flashlight before that is unable to save its settings unless stated otherwise.