New AAA-P's - Short Tubes?

Got a few AAA-P's for myself & gifts to family.

Noticed that the head/bezel seems to stick out a little more than pics I've seen of the AAA-P:


Tried w/Duracell AAA's I got from Costco and Powerex NiMH 800 mAh AAA's and the head still sticks out a little.

Is this normal?

Thanks.

if head shows oring, it's sticking out too far.

you need to send back to ARC or remove some solder to lower height of head. possibly the stainless pin is not pressed in all the way.

Definitely send it back. That is about a full turn and a quarter too far out.

that's not normal, mine is not like that. u should definetely warranty the light.

I just received my ARC-P yesterday. I am unhappy.

I have the exact same condition as you do with the O-Ring. However, to get to the position where you have shown a picture I ended up putting a very healthy dent into both the top and bottom terminal of the battery.

With a fresh battery, the O-Ring is not under the tube. I cannot see how the 100 ft waterproof rating applies.

Also, the adhesive on the donut is very gooey. It's probably past it's shelf life when applied, or some oils from the threads contaminated it. When I installed my battery for the first time that donut fell off. The second time I opened it, it stayed jammed down inside the tube making it hard to remove the battery.

I ended up removing the gooey adhesive from the donut and jammed the donut down to the (-) terminal of the battery (which works extremely well). Perhaps the manufacturer should consider dropping the adhesive and putting the donut at the bottom with a slight interference fit that exists now anyway.

I think I'm going to return my device. I strongly feel my unit is defective because of this issue. I shouldn't have to crush batteries to make the product waterproof.

Hmmm... I'm not entirely convinced this "defect" is a serious problem.

My new Arc-P has the same slightly-exposed O-ring issue, but I've already noticed that it is gradually receding as the little light "wears in." I also believe that "waterproof-ness" is heavily dependant upon timely lubing of the threads -- in ALL flashlights.

I wonder if Arc may have tweaked the design/tolerances of the battery contact studs to compensate for (a) long-term wear, and (b) subtle battery size variances?

I suspect Arc's Peter Gransee originally had to decide between (a) a SPRING (like the Fenix EO/E1 uses) to hold the battery snug under twisty-switch pressure, or (b) the solder-blob/metal stud/foam compression-ring design -- which the Arc uses. Peak lights also use a variation of the latter approach with their little rubber ring at the neg (-) terminal... and I've had their ring work loose/degrade on my Matterhorns, too.

Both approaches have their pros and cons re long-term wear.

However, the SPRING that the little Fenix lights (and some others) use will eventually lose its spring-force (AND ability to absorb battery-damaging shock from drops) under extended use (i.e., on-off compressions). That'll also inevitably beget "flickering" much like we've seen in lights like the little (springed) Inova X1.

I don't play an engineer on TV, but I do know that continuous compression-expansion of springs in firearms magazines ("clips" to the gun-illiterate) wears out those springs much faster than simple long-term compression alone. That's also why gun experts advise replacing certain semi-auto pistols' recoil spring every 500-1,000 rounds because of compression wear -- ESPECIALLY in some compact pistols where down-sized springs work harder.

Hence, the issue of design tradeoffs in flashlight design... made more sensitive with the parts-miniaturization inherent in Arc/Peak/Fenix lights.

In another current thread (see "Arc vs. Fnx EO" in LEDs) some folks mentioned that the ARC's knurling was too rough. I disagree... and find the Arc's rugged knurling (and thick anodizing) a nice ergonomic upgrade from the slippery finish of the Peaks. The Arc's exterior strikes me as much closer to the heavy-duty design of the superior, military-tough (i.e., tactical/beyond urban hot-house use) pricey-but-worth-it Surefires.

Perhaps Peter Gransee might wade in on this Tubes-Too-Short issue (or non-issue).

In another current thread (see "Arc vs. Fnx EO" in LEDs) some folks mentioned that the ARC's knurling was too rough. I disagree... and find the Arc's rugged knurling (and thick anodizing) a nice ergonomic upgrade from the slippery finish of the Peaks. The Arc's exterior strikes me as much closer to the heavy-duty design of the superior, military-tough (i.e., tactical/beyond urban hot-house use) pricey-but-worth-it Surefires.

Click to expand...

HAIII and the perfect level of grippy knurling on the Arcs is second to none...check out the thread bellow and ask yourself if your Arc-P will look like that in 5 months time...I sincerely doubt it.

https://www.candlepowerforums.com/threads/135086

My old AAA & AAA-LE don't look like that after several years of keychain carry and daily use...that's down to superior build and quality IMHO.

Battery thing is also a non-issue for me as the widest part of my o-ring sits ever so slightly bellow the top of the tube when off and disapears when on...which means it couldn't be any more waterproof even if the o-ring sat an inch bellow the tube.


CFU

Edit: not knocking Fenix - I own several and I like them...great VFM...I just don't accept they are equal to Arcs in build, durability or reliability.

Any proper switch has a spring and a pair of contacting surfaces. The contact system is designed so that a predictable contact force is delivered over a known range of travel. Other things come into play, such as size/materials used for the spring (stress relaxation longevity) and surface plating (resistance to oxidation and tarnish). But a reliable contact system starts with a spring.

The Arc has no spring. The foam donut has nothing to do with contact force being delivered. Instead, the torque from your fingers is converted into a compressive force in the axis of the battery. The minimum force is what's required to make enough microscopic surface contact spots that the required current can flow. This is in the order of 25-100 grams, depending on how dirty the contacts are. The problem is, the ARC has no maximum force limitation because there is infinite stiffness (no spring rate).

A screw is capable of exceeding this force by many multiples. When this occurs, something has to give. Arc has intentionally designed the tube and solder ball to have a point smaller than the battery terminals. This way, what gives is the head and tail of the battery due to the relatively large pressure (Force/Surface area, with less surface area).

This isn't a terrible thing, I notice most batteries are usually given a crease upwards at the terminal. But it's permanent deformation, not a spring.

The worst case for the ARC (assuming the LED head doesn't suffer) is what happens when the battery has been dented enough that the minimum force cannot be delivered to the battery anymore. The screw runs out of threads and bottoms out before delivering those grams of necessary force.

It's been suggested in a matter of words "who in their right mind would turn the head past the point at which the light comes on". Do some calculations, it's easy to deliver Kilograms of force to the battery instead of grams with just a tiny bit more torque.

It's not up to the consumer to delicately control the amount of torque to turn on the flashlight. It's our job to use the flashlight within a human range of ergonomics. It's up to the supplier to make sure that range of motion and force is sustainably handled by the device. It could be a ratcheting device, but if you go to this complexity you might as well have paid a real spring.

There is no need to worry about properly designated springs losing their force over time. There are lots of springs out there that last thousands of cycles through heat and fatigue cycling. Yes, they need periodic replacement. But their duty cycle is thousands of times more vigorous than a battery spring. Only cheap disposable flashlights have poorly tempered springs that lose a significant amount of their force over time and from being overextended, a $2 flashlight, not a $40 flashlight.

So now I've exposed some of my expertise. In summary, there is only two good things about not having a spring (1) It's cheaper to make, and (2) You can have a little less length to the device.

Right now I have the battery out of the ARC-P. I turn the head down as far as it screws into the tube. There is still a healthy gap between the top of the tube and the undercut space provided for it. The O-Ring is still in plain view. The tube could definitely stand to be longer. From pictures I have seen on reviews, I can see that it once was a better fit.

For instance, the picture copied below is from Arc's own web site. The overlap shown in this picture is impossible with the flashlight I received from them, even with batteries removed. This picture shows the unit lit, so I must assume they have a battery inside.

If there was an intentional change to the tube length to acommodate a greater variance in battery size and indentation through ON/OFF cycles, there should have been a corresponding change to the location of the O-Ring to keep it in the tube. Or perhaps they made this change, but had more heads than tails (thus I got a mismatched product).

EngrPaul, your engineer's expertise is much-appreciated here (and I sincerely hope you'll bring it to the table frequently, too). The beauty of CPF is the cumulative depth of technical and practical experience of its contributors.

I do agree that the Torque Control issue you described is a potential shortcoming of ALL springless twisties... including Arc, Peak, Infinity Ultra, etc. However, I don't believe it's necessarily a flaw.

I've never had a problem w/this with a dozen of these springless twisty lights. However, I can see where a klutzy newbie, or an elderly/arthritic senior person, or anyone under street-stress, might well over-screw the twisty and do some damage. (Heck, I'm gettin' kinda arthritic myself!)

I'll leave the science of flashlight Springs (design, metallurgy, stress) to folks like you. OTOH, as a handgun shooter, I've had extensive field experience with all kinds of factory-issue and aftermarket-upgrade springs. They can be extremely quirky and they DO fail (cause jams)... especially in downsized (compact) versions of Colt .45 ACP pattern pistols like the mini Kimbers, Detonics, and Officers Models. Some recommend replacing those guns' recoil springs every 500 shots -- as opposed to the similar (but longer) springs used in the full-sized versions of those guns (usually good for thousands of rounds). Why? For reliability.

The Lesson: miniaturized springs (at least in guns) are fussy and less durable. They wear out faster -- even the best ones -- under intense stress.

So, the issue here, as you clearly framed it, is pretty much about the ability of a Spring (albeit a tiny one) to reliably do the job of the Arc/Peak foam-and-blob/stud retention system -- versus the Fenix' spring system.

I suspect Arc's Peter Gransee has done his own extensive testing of subtle design alternatives for the nifty AAA-P. So, maybe he can weigh in here re this whole tube-length, thread-length, and related battery-compression issue.

But in the end -- and over the long haul -- the market will ultimately answer this question.

I have the same problem of a tube a bit too short, but only when I use energizer lithium aaa's. The o-ring is not exposed, but it is nearly no overlap when the light is off. So it gets a lot of dust into the groove! I bought the arc aaa-p about 1 year ago.

If the tube was 1mm longer, in all cases it would be better!

Maybe Peter can do some QC and add 1mm of material - for 40$ plus expensive shipping costs this should be possible.

jens

EngrPaul said:

The worst case for the ARC (assuming the LED head doesn't suffer) is what happens when the battery has been dented enough that the minimum force cannot be delivered to the battery anymore. The screw runs out of threads and bottoms out before delivering those grams of necessary force.

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Do you guys use keychain flashlights for torque contests? :thinking: With my ARC (or my lug-style Peaks, for that matter), I easily turn the head between two fingers until the LED comes on. There also are more than enough threads to compensate for considerable variation in battery length. So why should a switch mechanism have to withstand serious torque attacks when such force is completely unnecessary for operating it?

From that other post, it sounds to me that your battery got dented when you tried to force the light's head further down into the body than it would easily go (correct me if I'm wrong). Very likely your unit isn't right and may be best returned to the manufacturer, especially given its lifetime warranty. Using force on a new device that doesn't operate as it should is rarely ever a good idea, though. And in general, the ARC withstands more extreme force than most batteries.

Regarding consequences of the ARC's mechanism: I run my ARC on rechargeables exclusively, use it frequently, and noticed that the stainless steel negative contact leaves marks on the bottom of my batteries. So I decided to cycle just two of my rechargeables in that light. They both have gone through probably a dozen charge cycles each, with the number of on-off-cycles probably in the hundreds. Both batteries have *very slightly* dented blank spots at the bottom and still work perfectly fine. I do think that a larger and less pointy negative contact would be a good idea, but from all I can say until now, it doesn't really seem to matter that much in actual use.

There are slightly longer products that use spring-loaded battery contacts, if you prefer it that way. Personally, I'm glad my keychain light is as small as it is.

The problem with most flashlight springs is that the spring travel isn't given a bump stop. When you drop a light on the side of the spring, the inertia of the battery can overcompress the spring, leading to permanent deformation (the free length of the spring is shorter, and you get less force at the point of deflection). Meanwhile, the suface of the spring gets oxidized. These two problems lead to the condition of poor contact.

What it usually takes is grabbing the spring, pulling it a little past the free length you need, and letting go. Then take a pencil eraser to the top and clean off the erasure rubber with isopropyl alchohol. It will be almost as good as new. But depending on the spring material, the spring could eventually break.

There are usually two kinds of springs used. Typically tempered stainless steel or tempered copper alloy.

Stainless has the advantage of being a great spring, but it has relatively lousy conductivity and cannot be reliably soldered. A good grade of stainless that is passivated will typically maintain adequate surface condition given the spring force. However, unless the spring is a long, tapered spiral which can travel the whole way down to flat without yielding the material, it should have a bump stop. This could be a small ledge down in the tube, in which the spring goes deeply enough that the battery hits the tube before the spring material yields.

The better choice for spring material is copper-based. Raw copper has good conductivity, but poor spring temper. By alloying different metals into the copper, it is better able to have temper (can deflect and go back to it's original shape). A couple examples of copper alloys are "beryllium copper", "phosphor bronze", and "brass" (in order of performance). These coppers can be plated with a nickel, and for best performance plated with some gold. Usually it's given an inexpensive flash (3-5 microinches) of thin soft gold, the better thing to do for a high quality contact is 10X this much with a hard gold (gold alloyed with nickel or cobalt).

I agree that the contact design in the AAA-P can be a reasonable solution for a consumer flashlight. I'm not suggesting this flashlight is a POS because it doesn't have a spring... it has an excellent overall profile because of it's design, it would be bigger otherwise.

So far I've tried to not compare the Arc to another product, but at this point I think it's effective. Pick up a Fenix light that works ON/OFF with a twist. The barrel turns very smoothly, and when the light comes on it firmly stops. With your eyes closed, you can tell when the light is on or off.

Now pick up the Arc. When you turn the head, it is a lot more stiff. When the light comes on, there you see it more than you feel it (try it with your eyes closed). You're turning so firmly to engage the light that it's easy to go past the point when the light comes on and crush the battery.

I suppose this condition is because the Fenix's threads and O-ring work smoother, and partly because they have less components in the spring stackup (directly tail to LED circuit board, instead of through a battery to the middle of a board.)

Still, my major complaint is with the tube length not meeting the O-Ring without purposefully cranking down past the ON position, crushing the battery to get it there.

The flashlight has a personality of it's own, and I don't dislike it overall. If they can fix the tube issue, I won't mind putting it on the list of flashlights I like.

nocturnal said:

They both have gone through probably a dozen charge cycles each, with the number of on-off-cycles probably in the hundreds. Both batteries have *very slightly* dented blank spots at the bottom and still work perfectly fine.

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Thanks for your experience. This reassures me that the battery switch system in the ARC can be sustainable.

However, your experience also convinces me I received a defective unit worthy or return or exchange. My threads feel rough and gritty, not smooth like all my other devices I have. Also, it really resists even more when on the O-Ring. I cleaned the threads and addes a dab of Krytox, this hardly helped.

TonkinWarrior said:

EngrPaul, your engineer's expertise is much-appreciated here (and I sincerely hope you'll bring it to the table frequently, too).

Click to expand...

Here's a good resource for people who want to know more about the basics and terminology:

http://www.duracell.com/procell/design/batterycontact.asp

===

Also, if you look here, you will see recommended terminations. Screwing down on the cell terminal with the head of a sharp object is not listed as one of their recommendations.

http://www.duracell.com/procell/design/cavity.asp#ContactDesign

sounds like a tolerance buildup issue.
as for crushing the battery i doubt it would ever be an issue unless done intentionaly.
i have carried a aaa on my keyring since they have been availible and never crushed a battery.
and my freinds say i can break an anvil.
i am willing to bet this aaa has several thousand on-off cycles on it without the slightest problem.
every 6 months or whenever i think about it it gets a clean and lube.

PROBLEM SOLVED

By nature I'm a problem solver, not a complainer. So here's what I've done:

(1) I used the Duracell battery provided in the packaging instead of an Energizer brand. Evidently the Duracells are significantly shorter. This time, the tube reached the O-Ring (but didn't go onto it) when the light came on.

(2) I looked into why the head isn't going into the tube when threading. I used magnification and could see aluminum shavings in the threads. I removed these with a dental pick. Next I cleaned the threads and put the head on without a battery. For the first time, I could turn the head into the tube until the top of the tube meets the undercut on the head.

(3) I observed the thickness of the hemispheric solder blob [which makes contact with the (+) terminal of the battery] is about the distance of I need the bottom tube to go further onto the O-Ring. I proceeded to file the solder blob down until it is nice and flat (but still leaving some solder).

(4) As before, I pushed the foam donut down into the bottom of the barrel (after removing the gooey adhesive).

(5) I put some fresh Krytox on the threads, o-ring, and battery terminal.

No more "tolerance stackup" problem. The top of the tube now reaches the edge of the slot provided for the O-Ring a hair before the light comes on.

Whew! I'll be keeping my AAA-P now.

The Arc AAA is a good light but man people sure seem to bend over backwards to like them and justify the purchase.

Re: PROBLEM SOLVED

so the solution is pretty simple... file off a little of the solder blob

no biggie!

EngrPaul said:

By nature I'm a problem solver, not a complainer. So here's what I've done:

(1) I used the Duracell battery provided in the packaging instead of an Energizer brand. Evidently the Duracells are significantly shorter. This time, the tube reached the O-Ring (but didn't go onto it) when the light came on.

(2) I looked into why the head isn't going into the tube when threading. I used magnification and could see aluminum shavings in the threads. I removed these with a dental pick. Next I cleaned the threads and put the head on without a battery. For the first time, I could turn the head into the tube until the top of the tube meets the undercut on the head.

(3) I observed the thickness of the hemispheric solder blob [which makes contact with the (+) terminal of the battery] is about the distance of I need the bottom tube to go further onto the O-Ring. I proceeded to file the solder blob down until it is nice and flat (but still leaving some solder).

(4) As before, I pushed the foam donut down into the bottom of the barrel (after removing the gooey adhesive).

(5) I put some fresh Krytox on the threads, o-ring, and battery terminal.

No more "tolerance stackup" problem. The top of the tube now reaches the edge of the slot provided for the O-Ring a hair before the light comes on.

Whew! I'll be keeping my AAA-P now.

Click to expand...

^ I don't have any problems with my aaa-p so I've been very happy with my purchase so far. But if I had to personally file off part of the solder blob due to a design flaw then it would definetely change my opinion of this light. I feel that the premium pricing of the arc aaa-p is there for a reason including the quality and craftmanship. The need to modify a new light of this caliber is unacceptable imo.

agreed...you shouldn't have to modify anything on your new ARC. but if I had a simple to fix issue like this.

it's so simple to heat solder iron and remove a little solder VS sending back to ARC. or scrape a little solder off with your knife.

I'd rather take 5 minute to fix VS having to mail off to ARC so they can do the same.

this fix is nothing new... being adjusting ARC contacts for years. thought nothing of it..