There is something whacked in the software.
If it won’t turn back on with the 4.2 battery after having been on, just by twisting the head twice breaking contact and then Boom comes on fine until it is turned off again.
It is acting like an electronic lockout.
Doesn’t do it as bad with 1.2 Ni-Mh but still acts wonky.
What is the sequence for lockout on some of the other Manker flashlights?
Maybe software is the same?
I am just treating as a lockout feature for now 
Later,
Keith
Yeah me too… mandatory lock-out. So far this is the only thing wrong with it.
Sigh…
Got mine in today, only tried with Eneloop, same lock out problem…
Switch seems to be good though, but once turned off it won’t come back on unless i unscrew and tighten the tailcap first…
:weary: this sucks…
(edit)
Hmm… sometimes it does turn on, once every 20 clicks on average…
Maybe it is the switch afteral…
Very vague problem…
Good idea, that is, if everyone who bought one this time will vote.
I’ll start a poll.
So what do guys do with all these malfunctioning ut01 lights? Do you reach out to GearBest and demand a refund?
Try this;
Smack the flashlight (tail down) fairly hard onto a solid surface like you’re smacking a pack of Cigarettes and see if it doesn’t come right back on with a click after doing this.
The freakin driver assembly is free to move around, bad design.
I tried switching the tailcap and batt tube from my good one, no difference, problem is in the head.
Later,
Muto
I’m not going through the hassle of video, 14 PM’s and emails of bad translation and form letters for a $10 flashlight that works fine once you know what it needs to come on. It works fine once it’s on.
The older version I have does not have this problem, Progress they say?
Poll here:
Please vote to get an idea how many % is bad.
I may well open a ticket, yes.
See what solution they can offer.
I mean, a bargain is nice, but not when the product is faulty (obviously).
Just got mine today. So far, it appears to have no issue on either NiMH or Li-Ion cell, knock on wood.
However, visually, I don’t think this thing delivers 800 lm. Based on the results of the ceilingbounce app in my make-shift integrating sphere, lumen output is about the same as my JetBeam Jet-1 MK, which claims 480 lm on high.
Have you tried programming in the brightest setting? Some members suspect it comes programmed at a lower output level for its “turbo”.
Thanks. Programming to the brightest turbo setting helped. Looks like I’m getting upwards of 600 lumen now. I’m guessing the 800 lumen factory rating is for the CW emitter. Mine is NW, so it’s going to be lower. Plus, the cell I’m using (Sanyo UR14500P) isn’t exactly a high drain cell either, so that may also be limiting my output.
I don’t believe this light is spec’d for OTF-ANSI Lumens. IIRC the 800L is spec sheet emitter lumens.
Glad you got it re-programmed, and yours works fine with either cell chemistry.
It most certainly doesn’t do 800 OTF. I am not sure what the current draw is, but theres a good chance without an IMR cell you could be pushing the limits of the 14500.
Just a note: the problems with this light are not because of loose driver, bad contacts, or a bad switch. The switch however, is what manifests the problem. The problem is how firmware decodes the signal from the switch. When the light is off, something in the firmware tightens up the parameters that determine whether the button was pressed or not. Reason for this is unknown but I’ve wondered if it more “picky” with the handling of the signal from the switch to limit accidental turn ons. The firmware may not be broken through as it verywell may have worked with the switch used in testing(which may have not been actual physical switch at all). I say this because the light works fine with some switches and does not turn on at all with others. All my testing was done with the driver outside of the light so all other theories of mechanical problem from the host can be dismissed. Of course there is the normal one or two lights out there where this could be the problem.
I’ve read about all reported issues and all of them can be explained by my theory. Someone claimed my theory is in correct because their light started working when they straightened a twisted driver. However aligning the switch and pressing the button from a better direct angle changes the signal profile of the button press. It gives a better clean click so the driver reads the presses correctly.
Another claimed the problem is with the type of battery or because of different charge levels. These observations are probably correct but it doesn’t disprove my claims. Different voltages will also mess with the way the firmware views the signal from the switch. Either the voltage from the switch or the internal reference voltages of the MCU can be affected by different input voltages. This was confirmed by using a power supply to test the driver. Different voltages did affect the chance of the light turning on. Though, there wasn’t a general rule that deterermined what voltages did what. Each switch was different.
So, changing the switch may help defective drivers but not because the origional switch was “bad” it was instead not compatible with the firmware.
Good firmware design should take these factors into consideration. In fact, the designers of this light would have had to concider these things to some extent or the light wouldn’t work at all. The designers, however, must not have been thorough enough to acount for hardware variations.
This is my theory atleast. I admit, I am not fully qualified to make these statements. So maybe someone with a scope and a better understanding of firmware and switch press debouncing will test this theory further.
Sounds logical to me!!
I’m getting about 1.3-1.4A current draw on the highest Turbo mode.
I also wanted to mention, UT01 works great as a walking light, attached to the brim of a hat. On ‘High3’ setting, using a high capacity NiMH cell, it’s bright enough, and gives more than 80 minutes of runtime.
Oh wow thats way less than I was expecting!! cool
Took the chance on the UT01 for $10. So far mine is OK from what I can tell.
Used the 14500 at first and was hesitant to change to NiMh for fear to “confuse” this thing or mess up what was so far a good working light. I did the swap and all seems OK here too.
Pretty impressive on AA NiMh Tenergy green flat top made for pack builds. No Eneloops in AA.
For 14500 I have Windy cells from MtnE that are supposedly good higher drain and I have used them in SC Quads at 7A+. 14500 is brighter but not really too impressed with the difference to my eyes indoors. I have changed the outputs in menu.
I have another on the way and would be interesting to see the side by side difference in the cell chemistry.
My tail spring board came unglued on the second battery change. Easy enough to fix and I wanted to figure out a magnet for it anyway and possibly spring bypass but doubt its really needed.
Saw some talk about backwards tube but I looked closely, measured some things but my tube is identical on both ends. Pics are gone on Giorgoskok review so I have dug further for other pics to compare mine.
Took the head off to see whats in there. Got blue-goo boogers in the reflector and lens but wasn’t hard to open. Logo on bezel still lines up with SW after reassembly. Like how the reflector tightens down on the MCPCB. Will take it apart further later on to get the reflector cleaner and change the thermal compound, check shelf machining etc.
I got the NW 5000K but seems pretty Yellow for 5000K to me. At least its not Green. But I like it.
So far in the short term, I like the light and glad I bought it.
I did get some extra literature in my box. Thought this was funny.
Huh? A Lumintop warranty card in a Utorch box?
Food for speculation? (like why Lumintop after all these years finally manages to come out with a AA light with a driver done well, that even looks like the UT01: the EDC05)
