Discussion : - Utorch UT01

I think they probably will; most of mine accept Eneloops and Imedion NimH. If they are too long, I’d definitely try the ‘copper-wire-loop-in-the-tailcap’ trick. A circle made from thin silver solder wire works too, and it’s easy to form.

One of my lights was ‘iffy’ until I added a bit of length that way. Works perfectly now.

I think the tubes and tailcaps have manufacturing variances in their lengths. Incidentally, if you can find one of those cheap, skinny little split rings that sometimes come with key tags from the Dollar Store, they fit inside the tailcap perfectly and add a millimetre or so.

If I were getting any more, I’d check one thing before I ever put in a battery - if there’s zero gap between the tailcap and the corresponding shoulder on the tube, I’d address the length issue before risking crush damage to the driver with a too-long cell.

Thanks for your help! Have a UT01 on the slow boat from China and was going to pick up some Laddas. I'll let y'all know if they work.

me also. shipped on 12/11. Should be getting close :wink:

arrival! I was inspecting the light, it looks good. Didn’t know it had double springs in the tailcap. I’ll report back later after playing with it.

by the way here is the tracking site that works: http://www.sky56.cn/english/track/index

I was using that track17 one and got nothing. This new one showed my light had arrived in the USA on Dec 22nd! So 15 days in the U.S. until it reached me.

edit: light works great after adding the wire in the tailcap. Would not come on before that. Thanks for the tip Forum! I have neutral tint and it is very pleasing to me. Running on a NiMH. Great offering at $10.

I just got a UT01. First issue was that it was touchy about length of cells; longer protected 14500s did not allow the tailcap to make contact, and a small piece of copper wire inserted in the tailcap did indeed resolve that. The second, more substantive, problem has not been resolved. After you turn the light on it will go through the levels OK, but when you turn it off it won’t turn on again until you loosen the tailcap to break the circuit (this is stock, without the additional wire in the tail) and then tighten it again. It does this with every type and length of battery; it appears to be a driver issue (?). Any one have experience with this fault? Also, the one I received did not have the ability to go into the program mode to adjust output levels, which is not as big a deal.

My Ut01 is scheduled to arrive this Monday or Tuesday. Wonder what my fate holds in store for me concerning the flashlight. Work or no work is the question. My Lumintop Edc05 seems to be lost in transport. No update info since December 25, 2017.

I have the same problem as Rock with the one I received recently.

I have 4x UT01 now. Two work perfectly. Two have the common issue with requiring a power-cycling after being turned on once with unprotected 14500.

I’ve observed that battery length and perhaps clearance in the head seems to be an important contributor. My hypothesis is that the spatial tolerances in the head are such that with too much pressure components pressing against things they shouldn’t. This leads to cracks in solder, which leads to a open or higher resistance in some key circuit. The excess pressure probably comes from trying a long cell, like a protected 14500.

Swapping in a shorter cell, relieves the strain and allows the cracked joint to make contact again. Putting in a longer cell, like an un-protected 14500 opens up the gap again.

The glue holding the driver board breaking loose could also trigger the problem because it allows the driver assembly to be pressed further/harder into the head.

Replacing the switch itself may not actually be what solves the problem. Rather, the process of replacing the switch may close the cracked joint again. If the replacement switch is slightly smaller, that may also help by reducing the pressure that causes the break in the first place, and opens it under too much pressure.

Rotating the driver board slightly to center the switch may move the switch out of the way of something in the head cavity it interacts with and/or it may give the driver assembly slightly more room because of lack of uniformity in the depth of the adhesive between the top of the driver and the ledge in the head cavity it presses against.

My earlier observations that battery voltage seemed to be a contributing factor may actually be explained by the fact that my NiMH cells are slightly shorter than the alkaline I tried, which are slightly shorter than the flat-top LiIon 14550 I tried.

When I get a chance, I’m going to see if putting something between driver and the ledge of the head cavity helps.

Just received my Ut01. Seemed to be DOA. No matter what I did it would not work. Used freshly charged Eneloops. Suddenly started working with only high,low. Then fizzed out. Realized head was a bit loose. Tightened both flashlight head and tail cap. No works just fine. Has all modes working.

Looks like I got lucky. Mine arrived yesterday and works flawlessly. Using Efest 700 (red) batts.

My EDC05 arrived today. Well built and very nice warm tint. It is a good 4mm longer than the Utorch ut01. Protected 14500's fit with lots of extra room. No longer exact copy of the Utorch. Solder joints much better also than the Utorch.

I have the same problem with my UT01

I’ve tried it with regular short alkalines, with Eneloops, and with unprotected 14500. All lead to the same result - you have to cut power to the driver via loosening the tailcap before it will power again. I also took a quick look at the little spike jobbies sticking out from the driver, and they aren’t long enough to contact anything on my cells. The driver seems flawed. As an aside, this driver also will not go into program mode, so maybe they were forced to remove the program mode and broke some other aspect along the way (?). Keep me posted, guys, if you unravel the mystery any further. Thanks.

Welp.

Update: Now it will only turn on if I'm using regular alkaline AAs. The length of those seems to be identical to the Efest 700mah (red) 14500 I was using before. What gives? It's not the Efest batts as I tried three of them fully charged and none would get the UT01 to turn on.

So strange.

I agree completely with eas. I ended up using a circle of thin silver solder in the tail caps to give a bit more length.

I suspect that many of these issues start from the tubes being too short, and the initial battery install causing permanent crush-force damage to the driver.

Every one of my four had the anodized edge of the tail cap making contact, or almost making contact, with the anodized lip on the tube when I received them. Only a hard tightening would result in contact of the conducting surfaces. I added length and the problems disappeared.

Have any photos of how you did it? Where in the tailcaps?

When i tried a protected 14500 in the Utorch Ut01 it was dead. Nothing. I traded the body and tail cap of my new Lumintop EDC05 and the Ut01 worked fine. Has to be an issue of length. The body of the UT01 is just to short to work correctly.

(Reply to Mtonne here, but my post ended up in the wrong place)

I don’t know how to post pics here, but it goes right up inside against the inner circumference of the cap and up against the outside edge of the switch plate. I used 1.6 mm rosin core solder (.062”) and its just right. Not too stiff and not too soft. Adds just enough length. Wrap a piece around an AA cell, and you’ll be pretty close in size.
Trim to length with your nail clippers.

It should end up the same size as the shiny end of the tube, so it squeezes between the end of the tube and the switch plate - hence increasing the inner length of the tube by 1.6 mm. Wiggle it in there with tweezers.

Other materials will no doubt work as well, but I find the piece of solder is just the right softness to form easily into a circle and sort of squeeze into place and stay there. (Just don’t use acid core solder, that’ll mess things up for sure).

Thanks so much for the explanation. Makes way more sense now. I've got rosin core solder so I'm going to try it out now.

I too believe this may be causing some of the issues. My UT01 would not work with any of the alkaline batteries I had on hand, the battery tube is too short and the spring bottoms out before the tail cap makes contact with the end of the tube.
The unprotected Sanyo 14500 worded well. Tried the alkaline’s and just jumped from the rear of the battery to the end of the tube and they all worked.
As others have mentioned, a small diameter wire formed into a circle that fits around the outside edge of the spring and the tail cap will fix the problem, for my light anyway.