Problem with Surefire A2?

I recently bought a new Surefire A2, and was initially impressed, like so many others, by the incandescent light. Although the beam was not as perfectly round as my E2E, I believed the voltage regulation feature would more than compensate. However, with the initial set of batteries, the lamp initially dropped out of regulation in what seemed a surprisingly short time, and then intermittently went in and out of regulation for awhile. So I put in a fresh set of Surefire batteries, and timed the runtime of the incandescent lamp. After 39 minutes, the lamp dimmed (presumably dropping out of regulation) for about 45 seconds, then brightened again to full intensity. Over the next eight minutes, the lamp alternated intermittently between the dim and bright levels, and then finally stayed dim. The lamp continued to gradually dim further, until the filament went completely cold about 15 minutes later. The net result is that the incandescent lamp is reliable for less than 40 minutes on a set of batteries, which is disappointing.

Now, this does not sound like the behavior described by other A2 owners on CPF. And the runtime chart in QuickBeam's review indicates a longer time in regulation, and does not indicate a period of intermittent dimming and brightening as the light falls out of regulation. But, before I call Surefire, I am very interested in hearing if the behavior of my A2 is typical of other units out there. I will certainly be grateful for any input you care to offer.

I have learned so much already from CPF that it is probably audacious of me to make my first post an imposition for help. I hope I can be on the contributing side in the future. Thanks.

--Chuck

Welcome to CPF.

I've never done a runtime test, but the A2 incandescent normally dims before it shuts off. The first time it did this I thought there was some thing wrong with my light.

Now I just replace the batteries when it dims.

Yeah, my A2 will sort of flash from bright to dim several times when the batteries are depleted, I think it is the A2's way of telling me to change the batteries. I wouldn't run the incandescent when it is dim as that underdrives the lamp could cause premature discolouring of the glass. 39 minutes does seem about 10 minutes too short, though try experimenting with other battery types. Some batches of SF batteries seem to have QI issues every now and then. But overall, your A2's performance sounds pretty normal.

It's a battery issue. The manufacturing of 123's is apparently not precise enough so that all batches of them are identicle.

Also, the temperature is key. If you did your runtime test in cool or cold ambient conditions, this would explain the difference.

As for the A2 incan runtime, please keep in mind that this is a 2 level light. When it drops out of regulation and the incan no longer runs at full brightness, the batteries still have 25 percent of their capacity left to run the LED's for many more hours. It was designed this way intentionally, for a number of reasons. But in any case, most people will not normally run the incan continuously until it dies. In most situations, you can get by with the LED's on constant, and with intermittent usage from the incan. If you only ever intend to run the incan, keep in mind that the A2 will never get more than about 75 percent from your batteries before shutting down.

As for the beam profile, a transverse filament focused for maximum throw in a textured parabolic reflector will, of necessity, be oval. If the hotspot were made round it would not throw as far. No getting around that.

In a few days I hope to post my thread on the A2 with lots of info along these same lines. So I don't want to tell people how I know these things or argue about them at this time. Such discussions can take place in my "SF A2" thread that I will be posting soon.

Thanks, gentlemen, for your replies, although I must admit I would rather have heard that my A2 had a faulty regulator. Using Surefire batteries from the same batch in the same conditions as for the A2, my E2E (with MN03 lamp and roughly the same maximum output as the A2) will still produce about 75% of its maximum output after 40 minutes (which seems consistent with Brock's measurements, also), at which time the A2 goes out of regulation. The E2E will then run for another 20 minutes or so before reaching about 50% output (46% at 70 mins. per Brock's table). Also, if the batteries from my A2 are removed when the incandescent lamp drops out of regulation and inserted in the E2E, the latter will produce a light which has dimmmed, but is noticeably brighter than the dimmed A2, for some additional period of time (which I did not measure). So I have learned that the voltage regulation in the A2 is a double-edged sword, with a significant trade-off: a consistently bright white light, at the cost of run time, and with no visible indication of diminishing battery capacity prior to the "big drop" in light output.

Jim, I look forward to your new thread on the A2, and will hold off on any further discussion until then.

Chuck

Chuck,

OK. Then it isn't the batteries, so something important is wrong with your A2. It may possibly be the regulator, but this is unlikely.

The most likely possibility is that there is some contact resistance somewhere. If some stuff gets on the floating contacts inside the LOTC of the A2, it can cause a situation where the voltage to the regulator is less than the voltage actually across the battery stack. Take a look inside your tailcap, and also at the butt end of the rear of the light (where the TC contacts mate) and clean everything thoroughly just in case. Nice soft cotton pipe cleaners work great to clean those small contacts inside the tail cap.

But, certainly, something is wrong. If the batteries are powering the E2e for the correct amount of time, then they most definitely should power your A2 for very close to the full 50 minutes of in-regulation incandescent running.

As for regulation being a double edged sword, that in general, is not an accurate statement. It's just that in this application, with the dual level setup, and the way that switching is implemented, that it turns out this way. It doesn't need to be that way, though. You can make a regulated light which gradually fades out (as in a normal direct drive light) after reaching the end of regulation.

In the A2, there is no provision for this, nor are there any warning flashes directly built into the regulator, because you will still have the LED's, and thus will not be left completely in the dark, and because it will warn you by exhibiting the odd end behavior. If you turn off, then turn back on, you can always get a minute or so of additional light from the incan if you need it.

SureFire could have set the regulation voltage set-point lower, and made the incan run for longer, leaving the batteries with less juice for LED only running after the end of incan running, but they didn't for whatever reasons.

At least one reason is the difficulty of making efficient medium to high powered incandescent lamps that are down near or below 3 volts. The LVR's are buck regulators only, so you have to match the end of run or near end of run voltage to the set-point. For 2 123's, that would mean something like 2 volts. To make a 5 watt filament that is 2 volts, would mean a 2.5 amp draw. I'm not sure, but I suspect that the lamp laws more or less prohibit a desireable filament with those parameters. It would be thick and short, and not able to be wound into a tight coil. This would affect throw and beam profile. Plus, it seems that low voltage filaments like that can't be made as efficient.

Anyway, however that may be, there IS something up with your A2. If cleaning doesn't help, contact SF CS.

Chuck,

OK. Then it isn't the batteries, so something important is wrong with your A2. It may possibly be the regulator, but this is unlikely.

The most likely possibility is that there is some contact resistance somewhere. If some stuff gets on the floating contacts inside the LOTC of the A2, it can cause a situation where the voltage to the regulator is less than the voltage actually across the battery stack. Take a look inside your tailcap, and also at the butt end of the rear of the light (where the TC contacts mate) and clean everything thoroughly just in case. Nice soft cotton pipe cleaners work great to clean those small contacts inside the tail cap.

But, certainly, something is wrong. If the batteries are powering the E2e for the correct amount of time, then they most definitely should power your A2 for very close to the full 50 minutes of in-regulation incandescent running.

As for regulation being a double edged sword, that in general, is not an accurate statement. It's just that in this application, with the dual level setup, and the way that switching is implemented, that it turns out this way. It doesn't need to be that way, though. You can make a regulated light which gradually fades out (as in a normal direct drive light) after reaching the end of regulation.

In the A2, there is no provision for this, nor are there any warning flashes directly built into the regulator, because you will still have the LED's, and thus will not be left completely in the dark, and because it will warn you by exhibiting the odd end behavior. If you turn off, then turn back on, you can always get a minute or so of additional light from the incan if you need it.

SureFire could have set the regulation voltage set-point lower, and made the incan run for longer, leaving the batteries with less juice for LED only running after the end of incan running, but they didn't for whatever reasons.

At least one reason is the difficulty of making efficient medium to high powered incandescent lamps that are down near or below 3 volts. The LVR's are buck regulators only, so you have to match the end of run or near end of run voltage to the set-point. For 2 123's, that would mean something like 2 volts. To make a 5 watt filament that is 2 volts, would mean a 2.5 amp draw. I'm not sure, but I suspect that the lamp laws more or less prohibit a desireable filament with those parameters. It would be thick and short, and not able to be wound into a tight coil. This would affect throw and beam profile. Plus, it seems that low voltage filaments like that can't be made as efficient.

Anyway, however that may be, there IS something up with your A2. If cleaning doesn't help, contact SF CS.

Thanks again, Jim, for your advice, and for taking time to explain things. You are right, of course, that my remark about voltage regulation being a double-edged sword should have included the qualification "in this particular case." Until I experienced the behavior of the A2, I had a rather naive picture of voltage regulation as being a panacea that every decent flashlight ought to have. What I have learned, in part from you, is that it is not that simple. For example, the Peak 2005 CPF Special, I now realize, was designed to take advantage of an unregulated circuit (in conjunction with a rechargeable battery). I realize now, also, that there are many factors affecting both the need for, and the design of, the regulator, including the discharge characteristics of the battery, the intrinsic run time of the lamp/battery combination, and so on. I'm learning, I hope.

Now, Jim, I am threatening to go off into exactly the sort of tangent that you want to avoid until your new thread is up, and so I will retreat to clean the contacts in my A2.

Chuck

CLB,

Tangents are fine. I didn't intend to try to dampen discussion. I just didn't want someone to start arguing with me. I wasn't in the mood to argue about it and tell how I know the things I stated and get into a back and forth about it.

But you know, this is your thread, talk about what you want! No problem. I really only just wanted to avoid someone challenging me at this particular time, 'cause I won't defend my statements right now. Take em or leave em kind of thing. But discussion is good. Bring it on if you want.

My runtime results with Amondotech and Battery Station cells gave me runtimes of 40 and 42 minutes respectively. This was immersed in water for cooling and run contantly.

Floating Spots,

Don't immerse in water and those runtimes will go up. Primary 123's lose capacity with temperature quite dramatically. Check out A paradox to thermal relief?.

This is why your runtimes are 10 minutes short of the standard 50 minutes which is quoted for the A2.

Thanks FS for your input, and Jim, for the link to the very interesting thread on the effects of temperature on battery performance. If the consensus there is correct, then Floating Spots negatively affected his runtime by immersing the light in water, but positively affected it by running with the light constantly on. In my case, the light was at coolish room temperature (around 68 degrees F), and I ran the light in 15 minute increments, at intervals of several hours. So I had one factor positive (perhaps) versus Floating Spots, and one negative. If QuickBeam does his runtime tests at 70 degrees, say, with the light constantly on, then both factors would be positive in his test (by comparison with mine).

I'm beginning to doubt that there is anything "wrong" with my A2. Given some normal variation in individul batteries and lights, combined with the effects of temperature, my 39 minutes may not be out of line with QuickBeam's 50 minutes. Does that make sense?

If so, then, I return to my original concern about the A2. The advertised rating of 60 minutes in regulation certainly requires "interpretation." I use my A2 on my boat, in a way that seems very close to the designed purpose. As in Surefire's own description of pilots, I use the two modes in mutually exclusive ways: the LED to preserve my night vision while reading charts, and the incandescent light to identify medium distance objects such as channel markers, berth numbers, flotsam, and so on. When I need the incandescent light, the LED will not do, nor do I often have time to change batteries (nor to wait a minute for another short burst of bright regulated light). The combination of the short runtime and the regulated light (with no way of knowing the remaining capacity in the batteries) is turning out to be a questionable design for my purpose, and I would think for many pilots as well. My E2E lets me know, while still being usable, that I need to start thinking about changing batteries, but the A2 does not. When you combine this with the short runtime, it's a double whammy. My point is simply that I did not understand the tradeoffs involved in the design, and, as a neophyte, I wish these limitations had been pointed out either by Surefire, or in the many glowing reviews. Perhaps you will address this in your upcoming thread.

Chuck

Well, Chuck, I think there is indeed something wrong with your light; or you have a consistently "bad" lot of batteries.

I used my A2 extensively during the Katrina unpleasantness, much like you describe; some incan, some LED, for bursts of each. Some short "bursts", some long (5-10 minutes). While I admit to being too busy to actually time the "bursts", there were a few occasions when I got two 12-hour (or longer) night shifts worth out of one set of DuraCell 123s.

39 minutes for the incan seems 'way too short of a runtime, IMO...

CLB said:

My E2E lets me know, while still being usable, that I need to start thinking about changing batteries, but the A2 does not. . . .

Click to expand...

Chuck,

I agree completely. One of the things I look for in a regulated light is how it dies. You don't want to be starting something important in the dark and be worried that you don't have enough runtime left.

My solution is to use keep the A2 topped off with fresh batteries. I use my SureFire G2 more frequently, so I run batteries through the A2 first, then into the G2. The A2 gets a fresh set when the G2 gets a change.

I think the best solution is t have a spare flashlight, or perhaps in your case to switch to your E2E and a Photon Freedom.

Scott

Well, Jim, I cleaned the little contacts in the tail switch, and lo and behold, with the same batteries that prior to this had no longer been able to provide regulation level voltage even briefly, the light now produced about thirty seconds of bright light on the first burst. With short rests in between, I coaxed another minute or two of brightness over several succeeding bursts. So it seems that my short runtime was indeed at least partly due to resistance in the contacts. I admit I was skeptical about this, because the light was brand new, and because there was little or no visible evidence of anything on the contacts. I hope this doesn't recur often, but am glad to know about it; thanks. So, considering this, along with the temperature factor and the intermittent use during my runtime test, I will assume that my A2 is probably ok. I don't plan to run another continuous runtime test now, but will try to keep track of the time in regualtion on the next set of batteries. I plan to do this once out of curiosity, but the need to track cumulative runtimes in order to know the remaining battery capacity has already ruled out the practical utility of the light for my intended purpose.

Thanks, Steve C for your input. And Scott, you must have been reading my mind, as a Photon Freedom and an E2 (or G2, etc.) is exactly the solution I intend to use on the boat. Your battery rotation idea is very clever, and I may be able to adapt it to make the A2 more practical in other uses, but not on the boat. I have enough to worry about on the water.

Chuck

Well, after discovering Pizzaman's thread on his problems with Battery Station CR123's in his A2, I tried a set of new BS batteries in my A2, and, like you, Scott, got only 12 minutes of regulated light. So, in frustration, I sacrificed my last set of new SF batteries, and did another runtime test, with the newly cleaned contacts. This time the light ran 49 minutes continuously before dropping out of regulation. So, I conclude that my A2 is "fine", i.e. functioning normally. But not fine for me and my intended use for the A2. I will chalk it up as a learning experience, and it seems from the A2's popularity I should not have trouble selling mine.

So, thanks all, for your help.

Chuck