LiteFlux LF5XT - the ultimate AA light? (Part 3)

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kaichu dento

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Part 3 already!

At least there seems to be some attention being given to the problems addressed with the LF5XT. Let's hope they get at least the cutting out problem solved.
 

Thujone

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I tested the black LF5XT that I had given my brother in law last night. With a fairly stiff smack it will indeed turn off. But not from setting it down on a table or anything like that. My replacement head should arrive today or tomorrow. Will check it out then.
 

matrixshaman

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Hmm.... I can't believe I didn't think about Eliteled as being a U.S. distributor earlier when this was being discussed. Afterall I bought one of my 2 LF5XT's from Gary. Glad to see there is local support and info coming through on these. Thanks for chiming in here Gary.

As I've said in some previous posts this 'tap-off' problem seems like an issue for some but for myself it is no longer an issue in my useage. I would like to see something done with the O-ring problem as that's an obvious and easy fix I believe. Every time I screw on the tail cap it feels like I'm stuffing an overly fat belly into too small of pants. First stuff it in on one side and it pops out on another.... How's that for a visual :crackup:
 

matrixshaman

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by TooManyGizmos
I will offer a solution to the rear Tap/cutoff's on LF5XT's

But first a quote from GBH2 about the spring tension :

Quote:Originally Posted by GBH2
I removed the head and tried alternatively compressing the battery and the brass sleeve(compressed using my fingernail). It takes far greater force to compress the sleeve than it does the battery. Also, if you think about it the the sleeve is comparatively light and has to overcome a fairly strong, almost fully compressed spring(tailspring) while the battery is comparatively heavy and only has to overcome the weaker, only partially compressed battery tube spring.

I haven't taken apart the pcb's in the head to see if there is a potential problem there.

.................................................. ...............

This is what I have been saying ..... so I agree with GBH2 on the way that he explained it.

I think the current design allows the "+" battery terminal to loose contact if the light is bumped on the rear.

The way it is - the two springs are counteracting and fighting each other. Increasing the tension of the battery spring will counteract the tension of the tailcap spring, because it pushes the brass piston rearward against the pressure of the tailcap spring ....... thus causing a tendency for even the brass piston to loose contact with the front contact ring. In other words - stronger battery spring may cause either of the front contact points to break.


I can see only 1 permanent - long term solution to resolve this Tap/off (undesirable) condition.

It will require a design change :

Remove the exterior ridge at the rear of the brass piston so it can pass all the way thru the body. (removal needed for battery change reasons)

Put threads on the contact ring in the head , and threads on the front of the piston - so they can be screwed together making the piston stationary (not floating) which will eliminate the two springs fighting each other. The piston should not be allowed to move.

Then you can put a stronger battery spring inside the piston because it will now be stationary and screwed together with no counteractive forces on it.

.................................................. .............

For battery changes you would unscrew the head - slide the body to the rear over the stationary brass piston. Then un-screw the brass piston from the head to get to the battery.


This change would allow much more force to be applied to the battery and lessen the chance of rear Tap/cutoff's.

Well ....... that's my solution ...... do you have a better one ??

TMG - thanks for explaining how you tested your light with the tailcap off using C-clamps and thanks for the innovative thoughts above as a solution. It sounds like it might work. I do suspect there would be user resistance to having to unscrew two things to get to the battery. It seems it might also be likely to put some strain on the parts in the head after removing the tail and body. I see some possible design issues but I don't have any better ideas at the moment unless they went with a design similar to Novatac which uses a spring around the outside of the battery all the way from the tail to the head.
 

orcinus

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I see some possible design issues but I don't have any better ideas at the moment unless they went with a design similar to Novatac which uses a spring around the outside of the battery all the way from the tail to the head.


There's the one i suggested... Four springs - one for the battery "-" terminal, one for the battery "+" terminal, one for the rear (closed) end of the tube, one for the front (opened) end of the tube. Instead of a spring soldered to the contact ring, that last one could also be implemented as a ring mounted on a spring or two steel leafs.

That way, everything would be dynamically suspended and would adjust according to bumps and decelerations from both sides, without losing contact.
 

BabyDoc

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I am just curious about one thing. While I understand this turn-off problem is a real issue with the LF5XT for some people who just who casually toss their light on a table, other people don't seem to have a problem ever. Others only find a problem if they really give their light a heavy knock. I am not in the habit of throwing any of my lights around in order to see if they turn off. However, I am wondering whether other non Liteflux lights so treated wouldn't also exhibit this behavior with a heavy knock. If so, is there a minimum tolerable shock proofness that should or can be expected of a quality light? If so, how much should we expect?
 

HKJ

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I am just curious about one thing. While I understand this turn-off problem is a real issue with the LF5XT for some people who just who casually toss their light on a table, other people don't seem to have a problem ever. Others only find a problem if they really give their light a heavy knock. I am not in the habit of throwing any of my lights around in order to see if they turn off. However, I am wondering whether other non Liteflux lights so treated wouldn't also exhibit this behavior with a heavy knock. If so, is there a minimum tolerable shock proofness that should or can be expected of a quality light? If so, how much should we expect?

There will not be many lights with this behavior, this requires that on/off is controlled by a microprocessor. I have listed some lights that has this and all of them are candidates, but depending on construction they may or may not have the problem.

Far more common will be a level shift, when the light is bumped, because many lights uses a power interruptions as signal to change level.
 

BabyDoc

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Is EliteLED actually the US LiteFlux distributer, or just a US LiteFlux dealer? As a dealer, I am sure they will take care of problem lights sold to their customers. But if they are the distributer, will they handle service issues on LiteFlux lights shipped to the US from abroad? If Gary is still tuned into this thread, perhaps he can comment.
 

TooManyGizmos

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I thought Gary said he is the US LiteFlux distributer in his post. (part 2 - post 343)

But maybe I got confused - maybe I just saw it on his website after I followed his link.

This is a line from his website .......

Quote :
** As the LiteFlux US distributor, we are proud to introduce LiteFlux newest Cree LED
programmable models: LF5XT and LF2X. In stock now.
...............................................................

That's where I saw .... "The LiteFlux US distributor" .......... TMG:grin2:
.
 
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redsfairlane

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Dude, I don't generally toss my lights around, I just put them down.
I don't do it gently, I don't do it hard, I just do it same as you.

Every say third or fourth time I put it down, it goes off. depending what level it is on, depending if the tail or head touches first, depending on floor or carpet or desk etc.

Honestly it is way way more sensative than any other light I have handled, My Novatac will go off if I hit it hard enough, but I don't do that.

This is a really nice light, size, looks, AA battery, UI, etc, I'm not writing it off because of this problem, but it really is a hardware problem, not a user problem.

I am just curious about one thing. While I understand this turn-off problem is a real issue with the LF5XT for some people who just who casually toss their light on a table, other people don't seem to have a problem ever. Others only find a problem if they really give their light a heavy knock. I am not in the habit of throwing any of my lights around in order to see if they turn off. However, I am wondering whether other non Liteflux lights so treated wouldn't also exhibit this behavior with a heavy knock. If so, is there a minimum tolerable shock proofness that should or can be expected of a quality light? If so, how much should we expect?
 

varuscelli

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Dude, I don't generally toss my lights around, I just put them down.
I don't do it gently, I don't do it hard, I just do it same as you.

Yeah, as I stated before with mine, I can let it drop tail first to the table from about one-quarter inch (6 or 7 millimeters) above the table (a very short distance with very little force or speed involved, to my way of thinking) and it will cut off. I might equate the force involved with such a short drop to a very light tap on the tabletop with the knuckle of one finger. Not a casual toss to the table by any means (something I don't do, either).

But from the various descriptions, I think this varies from flashlight to flashlight, unless I'm misinterpreting.
 

LED-holic

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According to a video posted in part 2, the user ever so gingerly set the light on a flat surface and the light turned off, every time. That is clearly across a threshold of being acceptable.

A light needs to be robust enough to handle gentle jostling and bumps.
 

orcinus

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There will not be many lights with this behavior...

Actually, there's a SureFire E2DL thread describing a very similar problem, and there were mentions of other SureFire and non-SureFire lights with the same behaviour.

This can happen to nearly any light that doesn't have a double sprung battery and has any kind of regulation or switching that resets on power loss. It doesn't even need to have an MCU.

So it really isn't that special of an issue. The problem are those few LF5XT's (are they few? i've got the impression they are) that "overreact" and switch off at the (s)lightest tap.
 
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BabyDoc

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Dude, I don't generally toss my lights around, I just put them down.
I don't do it gently, I don't do it hard, I just do it same as you.

Every say third or fourth time I put it down, it goes off. depending what level it is on, depending if the tail or head touches first, depending on floor or carpet or desk etc.

Honestly it is way way more sensative than any other light I have handled, My Novatac will go off if I hit it hard enough, but I don't do that.

This is a really nice light, size, looks, AA battery, UI, etc, I'm not writing it off because of this problem, but it really is a hardware problem, not a user problem.


I am sorry that my wording wasn't more clear. I didn't mean to suggest you were abusing your light in any way that you made your light shut down. What I was trying to say (I'll try again), it seems some people are really having a shut down problem with just casual usage; others only with a heavy drop; and others NEVER, no matter what they do to the light. I never meant to suggest it was a user error causing this. I agree that it IS a hardware problem, but I find it strange that people are not experiencing the problem to the same extent, and some people don't have the problem at all. ( It reminds me of the D10/EX10 complaints that circulate. Some people had a problem with erratic operation and stiff switching; most people didn't. Some people solved their problems with lubricants, and different O rings; rotating contact rings, etc; some people didn't solve their problem but had no problem when they exchanged their light for another. )

I may be stating the obvious, but it would seem both NiteCore and LiteFlux have quality control issues with their new programmable lights, rather than just design problems. Did they both rush these to market before adequate quality control testing? Are the production tolerances needed for these high tech lights tighter than these new companies allowed? Unless I am missing something, proposing add on fixes like springs makes sense only if there are design faults in the lights. Can this be the case if some lights need fixing and others don't?
 

LED-holic

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I am sorry that my wording wasn't more clear. I didn't mean to suggest you were abusing your light in any way that you made your light shut down. What I was trying to say (I'll try again), it seems some people are really having a shut down problem with just casual usage; others only with a heavy drop; and others NEVER, no matter what they do to the light. I never meant to suggest it was a user error causing this. I agree that it IS a hardware problem, but I find it strange that people are not experiencing the problem to the same extent, and some people don't have the problem at all. ( It reminds me of the D10/EX10 complaints that circulate. Some people had a problem with erratic operation and stiff switching; most people didn't. Some people solved their problems with lubricants, and different O rings; rotating contact rings, etc; some people didn't solve their problem but had no problem when they exchanged their light for another. )

I may be stating the obvious, but it would seem both NiteCore and LiteFlux have quality control issues with their new programmable lights, rather than just design problems. Did they both rush these to market before adequate quality control testing? Are the production tolerances needed for these high tech lights tighter than these new companies allowed? Unless I am missing something, proposing add on fixes like springs makes sense only if there are design faults in the lights. Can this be the case if some lights need fixing and others don't?
I don't think you can compare NiteCore to the LF5XT. The LF5XT is much more limited in circulation than the NiteCore, and the complaints about the NiteCore having issues are relatively few compared to what I've seen on the LF5XT as a percentage of people who post. Not sure why you dragged the NiteCore into this discussion.

All lights have issues, no matter how expensive or well designed. I wasn't here for the initial Fenix L1D / L2D introduction, but I'm sure if I dig hard enough there will be plenty of user issues as well. I've read several people having problems with the SureFire Titan. Does that mean just because a small percentage of users have issues mean that QC is bad? We have to look more closely than lump the NiteCore into the same bucket as the LF5XT. IMHO the NiteCore lights have far less issues as a % of overall users than the LF5XT.

And this is not a slam on the LF5XT. It is a more ambitious light so it is going to have some issues. The other key difference is when users have issues with the NiteCore lights, 4sevens stepped up right away and helped to resolve these issues. With LF5XT unfortunately the distributors have their hands tied so it's not as easy for the owners of these lights.
 
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Thujone

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The other key difference is when users have issues with the NiteCore lights, 4sevens stepped up right away and helped to resolve these issues. With LF5XT unfortunately the distributors have their hands tied so it's not as easy for the owners of these lights.

With all due respect Khoo is a fantastic customer service provider as well as David. In a thread I mentioned flicker at a couple of levels and he privately offered replacement to me. And has followed through, my light should be here tomorrow.
 

yaesumofo

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one person suggests a redesign. another says more springs are necessary....
The design of this flashlight is complicated by nature.
If anything they should go to McGizmo where they "borrowed the piston portion of the design and ask him for some help, offering him some dough wouldn't hurt. One of the things Liteflux has done here is borrow a design element redesign it (in order to disguise the fact that in fact borrowed a design element (in the piston))for the worse.
The fact that the light turns off if placed down on the tail while on with varying amounts of sensitivity is a BIG problem. This is a fundamental design flaw. Unfortunately whomever suggested a redesign was correct. Now if this "issue" doesn't happen on the majority of lights produced then it might just be smarter to halt production do extra QC on existing lights and replace units in the field with units that do not have the "issue". While this is going on, create a NEW aa light based on the design of the electronics with a new switching design. I would highly recommend a less complicated design with fewer parts. Yes I believe that the light has to many parts, which open the door for "issues" like the one that apparently many people are suffering from.

I have to say that on the surface of things..without looking at all of the parts and the innards of the light...by just looking at the picture of the light and reading about it's features the LF5XT is an interesting light. Once I saw all of the parts I knew that we would see problems, and we have.

as a small company LiteFlux should be able to react rather quickly to this design problem. If they are to succeed they might have to in order to maintain the confidence of the light's owners.

I have one on the way. I have put my money where my mouth is. I am going to give the light a chance. If my light really suffers from this problem I will send it back to the company for repair replacement or my cash back. I will not however accept a light which is defective. I will not rely on a light which (if my light has the problem) may not be totally reliable.
I do hope that LiteFlux has halted sales in order to take stock of how big the problem really is. IMHO this is the most responsible thing to do.
I do not believe that it is ok to continue to sell a light with a known defect (if many of the lights which are being delivered have the problem.
For all I know it may be a subtle problem effecting relatively few units.
Yaesumofo

There's the one i suggested... Four springs - one for the battery "-" terminal, one for the battery "+" terminal, one for the rear (closed) end of the tube, one for the front (opened) end of the tube. Instead of a spring soldered to the contact ring, that last one could also be implemented as a ring mounted on a spring or two steel leafs.

That way, everything would be dynamically suspended and would adjust according to bumps and decelerations from both sides, without losing contact.
 

matrixshaman

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yaesumofo - hopefully you'll like your LF5XT as I do believe this light has a lot of desirable features. I do not think they borrowed McGizmo's piston drive feature though as it does not move like the Nitecore EX10 and D10 do. It is simply a way of getting the power to the MCU and instead of a spring like Novatac used they used a solid piece of brass which does not move when you push the switch. I think this is a nice looking feature making it attractive but unfortunately the design currently seems to cause some problems for some people with the tap-off. I think their use of the brass cylinder was a logical choice for an MCU designed light that was made to use everything from NiMH AA's to protected Li-Ion batteries - all of which have considerably varying lengths. I also think that the particular battery a person is using may have an effect on how bad the tap-off problem is considering the big variation in not only length but in weight differences. Consider how much lighter and thus less inertia a AA Energizer Lithium primary is compared to a NiMH. I get 0.7 ounces for the the primary and 1.3 ounces for the Eneloop NiMH - almost double the weight as checked on my postal scale.
 
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