It’s just a warning to not spend too much money on an impulse buy, because it sounds like that is what you are doing. But if not, then by all means carry on. The SR95UT will throw further than the ST90 btw.
You should consider a HID if you don’t have one. There are ones with bigger reflectors than the common flashlight format.
The St90 is direct driven SST90. Pretty decent value for hobbyist compared to pro olights.
Will ST90 has same throw compare to SR95 or SR90?
Never thought of getting HID. Any brand that is reliable and budget price?
I would think it’s in the same ballpark, but st90 is direct draw so will dim as battery fades.
Slewflash says his 85w from here is good. Page Not Found - Aliexpress.com
Make sure to ask for 4300K bulb.
When I bought it, they said 4300k bulb was only available if you ordered 50 of more. You’ll have to buy the 4300k bulb separately unfortunately. But ask if you can, they may have changed.
Thanks for the link.
How do I know it has big enough reflector? I am not familiar with HID flashlights.
If you want hardcore throw maybe look on aliexpress for a large (4”+) reflector like the SM5200 or SM5500, but that light has enough output that it compensates for the size (still not any worse than the leds).
about the 85W HID, if I left it at 45W on for hours idly, will it get very hot?
Is it good idea to use it to flood room with lights?
I’ve never tested the temperature on 45W, but it’ll probably only be around 10 to 15 degrees cooler I think.
You can use it to illuminate a room by tailstanding if you wish, but if the spill goes into your eye you’ll have trouble walking around the room, so put the head higher than your eye level, and don’t look at the roof when you turn it on.
Most of my lights application is indoor. So I am thinking will this 45W which is the lowest settings be too high. I like the highest 85W though.
So this HID will out throw TN31 and TK70 by a lot?
I am a bit worried about the battery used though, wonder are they protected. They have one using Panasonic battery at 9300mAH. But more expensive though.
Yes…
It seems they can do it now for any order. I just asked.
DENGOH, the “protection” is built into the battery block. Buy it! :party:
I communicated with Liu yesterday. The default battery doesn’t have indicator for the battery status. He can provide me one with battery that has status indicator, but cost much more but he didn’t tell me how much. He told me I can choose 4300k, no problem. Now my main concern is the battery. Also the reliability is one of my concern as I read that one got it and it doesn’t throw as far as the bulb is not pointing correctly? Also one guy actually burn a paper with the light pointing at the paper very close, I assume it will be super hot, wonder what will the heat do to the batteries.
After damaging one of my 26650, I started looking at flashlights with low voltage indicator. Even my cheapest ultrafire 501B has indicator by flashing light on and off. I have many batteries, some are protected, some are not. Non protected batteries have less voltage drop for high current. My Trustfire X100 doesn’t have indicator, now I just found that Thrunite TN31 doesn’t too, it will be just not able to go to highest mode, same as Fenix TK70. I mean to say batteries are important part to me. Will probably wait longer to study more about this China HID.
But no way I can get 8500 lumens with LED for many years to come at this price. So I might get it eventually. 
Thanks for the suggestions.
The TN31 does feature low voltage warning via blinks as per my review "Shortly after 123min, the low voltage warning (3-4 blinks every min or so) kicked and at 127 min, one of the RL3100's PCB finally kicked in terminating the run."
Then my TN31 is not behaving as it should be. I found that the output between the highest and 2nd highest is similar. Then I quickly take out the batteries and measure, two were 2V, one was 3V. I let them rest for two hours, two rise to 3V, one rise to 3.3V, then I start charging them.
Do you know what is the voltage for the low voltage warning? And can your TN31 still has highest output mode working before the low voltage warning kicks in?
As for the subtle perceived difference between L6 and L5, it's a common complaint and barring a genuine defect with your TN31, it's likely due to the way our eyes perceive brightness. I had written up this explanation for the TN30 but the same rule applies here.
Below is an excerpt of the runtime for L6 (review here). One of the PCB's of the 3 x RL3100's had tripped thus terminating the run but after restting, they were all around 3.26V (resting voltage). I have not tried whether L6 works w/depleted cells but will give that a shot in the future and post back results.
=======
RUNTIME
The relevant battery stats are provided above each runtime graph along with:
- Voltage of the battery at the start and end of the test
- Current draw as taken right before the test
- Actual runtime using ANSI FL1 (first in HR and then in M so for the RL3100 read this as 1.5hrs OR 91min)
- Also for High, captured the temperature: ambient, the head at start and the max it reached (fan was used for all bats)
As with the TN30, there is a subtle but distinct step down after 1.1 minutes, but it's only about 100lms. After that it does two more tiny step downs and then one step up as if trying to find a sweet spot and then runs just about nearly perfectly regulated for the rest of the run. Shortly after 123min, the low voltage warning (3-4 blinks every min or so) kicked and at 127 min, one of the RL3100's PCB finally kicked in terminating the run.
As can be seen, heat isn't really an issue and based on lessons learned from the TN30 run, I was able to validate that the highest heat point would be right aft of the control ring so I placed the thermocouple there. The TN31 only got to a high of 96F with the heat dissapation likely greatly aided by the large head, reflector and the copper heat sink within.
Thanks for the explanation. Really appreciate your input.
I think my perception is not wrong about L5 and L6, as when the battery is fully charge, I can see the difference between L5 and L6 clearly. But when the battery is low, they look the same to me. I am not saying L6 is similarly bright with L5, L6 is simply not as bright comparing to when battery is fresh. I know our vision will adjust to it, but it is not in instant. The difference of 500 lumens still can be perceived very easily to me.
Regarding the heat, I actually ask a question on CPF this morning, as below:
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Is it my TN31 having issue as I found problems below seems like no one mention about it:
1.The hottest location is on the magnetic rotary switch. By looking at it, the LED is indeed sitting on the same level on the rotary switch. But then after using the light for long hours, the battery tube get quite warm. If I take out the battery at that time, the batteries are quite hot. Temperature on the heat sink on the head seems to be not doing good job as they are much cooler.
2.The rotary switch has some play to it, it is not purely rotating when touching on it and rotate, seems to be a little bigger than ideal gaps between the rotary and body.
This is very good flashlight. Just want to make sure is this something Thrunite should improve for their future flashlight. Or it is isolated mechanical problem or my batteries problems.
——————————————————
I'll do some output measurements of L6 vs. L5 w/depeleted cells next time and post them afterwards.
During my testing, the highest temp I measured was just aft of the ring so you're assessment is very close to mine. I didn't notice that the batteries were particularly hot (I used 3 x RL3100's). While the batteries do make contact with the tube, keep in mind that it's largely isolated otherwise sitting in the carrier and not having a good direct thermal path w/the emitter. As such, I suspect it might be your cells, what kind are you using? Also, was the tube as hot as the area around the control ring? I measured a max temp of about 100F which isn't all that hot.
As for the ring play, I do notice there's a minute amount when I'm not rotating it but I certainly don't feel it during actual rotation/operation.
ThruNite actually has their own forum over on CPFMP as well as their personal retail stie: www.thrunite-store.com so you should post your concerns/feedback for them to address.
Cheers,
Tim
My cells are Moli unprotected cells. I suspect it was my cell too, as it is hotter if the cell voltage is low. I suspect when it is drawing a lot of currents, my cells are generating a lot of heat. But one thing I would like to point out is even my cells voltage is high, I found that the temperature is hottest on the rotary, then the battery tube, then the heat sink. Do you have same observation? Feels like the heat transfer more easily from the rotary ring area to the tube body than to the heat sink. I have ordered some EFEST battery, will try to experiment with the new cells.
Yes, that is the play I am talking about the rotary ring. Wonder could it be done that way to solve heat on ring issue as it might expand more when temperature rise, so have to have some play in it to make sure it can still rotate smoothly even it is hot.
Thanks for pointing out. I will post on Thrunite thread when I have more experiences on their products as I have just order TN30, will compare it with TN31. To me, definitely hottest point on the rotary ring doesn’t sound like a good design. Can it be designed this way so that user will know the temperature getting too hot and switch to lower level? But then it is wasting the mass on the heat sink that can act as thermal mass.
Apart from this, this is very good flashlight in terms of UI, build quality and output/throw. Long term reliability is not known yet though as I have my TN31 for about one week only.
Ok, did the test on low voltage indicator(LVI) feature again last night.
My original observation is not complete as I might have missed the low voltage indicator. Wonder is it my fault or the design of the feature that is prompt to mistake.
Last night, I pay more attention to it and found that TN31 start blinking on L6. I timed it and it blink every 25s. I let it blink 3 times to confirm the timing. Then I quickly take out battery carrier and measure 9.997 volt. Then I put the batteries back to continue to test. I rotate the level from L6 to L1 to make sure every level are still working fine. And they are. One thing that is not working is at some point, when the batteries are really weak, LVI is not working or “obvious”. I tested it until a point that L6 and L5 is similar brightness to me which is same observation as previous. And if I look at it hotspot on wall closely and hold my light steadily, it actually blink very very slightly that until now I still doubt is it LVI blinking. If I don’t pay very close attention, I won’t know it is blinking at all. At the end, I take out the battery carrier and measure 7 volt unloaded.
So my opinions about this feature is as below:
1.TN31 has LVI feature, it will blink every 25s when voltage is about 10 volt unloaded. (I wish it blink all the time instead of every 25s for reasons below).
2.TN31 LVI feature seems not working well when batteries are almost drained. And the trigger voltage level of unloaded 10 volt might be set too low because that is too close to completely drained batteries. Remember the 10 volt I measured is without load, so TN31 LVI trigger voltage is set much lower. I wonder do they have different trigger level for different brightness output level.