Surefire A2/U2?

I carry one of these (usually A2) on a daily basis. I use it frequently enough that I leave the 123's in it. Is there any draw, I guess the correct term would be parasitic, even thou the light is off? I have a Black Diamond hybrid headlamp that draws when off. I have yet to speak to BD, but I have been told that my lamp is not unusual.

I could be wrong, but I don't believe either the A2 nor the U2 exhibit parasitic drain.

-Robert

No parasitic drain on those. They use mechanical hardware switches, not electronic ones.
bernie

Bernie,

Do all lights with electronic switches have a constant drain? i.e. Zebralight H30-Q5.

I do not know, sorry. Possibly yes, but others will need to chime in.
All I know is that a mechanically interrupted path won't have a parasitic drain.
bernie

jw2n said:

I carry one of these (usually A2) on a daily basis. I use it frequently enough that I leave the 123's in it. Is there any draw, I guess the correct term would be parasitic, even thou the light is off? I have a Black Diamond hybrid headlamp that draws when off. I have yet to speak to BD, but I have been told that my lamp is not unusual.

Click to expand...

The A2 is my favorite General Purpose light, but I have thought about getting a U2 as well.

Since you have both, will you give me your opinions on them?

I have a U2 and it is my most used light (it is sitting behind me on a shelf right now!). It is very versatile and not heavy on battery consumption. The clip is great. It has been my going to the pub light all summer.

Hope this helps :wave:

I'm glad this issue was brought up, because I've been experiencing parasitic drain in my A2. I popped in a new pair of batteries and used the incan beam for five minutes, max. Six months down the road the batteries were drained quite a bit; there was only about 20 minutes left on the batteries.

Anyone else have a similar experience?

dudemar said:

I'm glad this issue was brought up, because I've been experiencing parasitic drain in my A2. I popped in a new pair of batteries and used the incan beam for five minutes, max. Six months down the road the batteries were drained quite a bit; there was only about 20 minutes left on the batteries.

Anyone else have a similar experience?

Click to expand...

They were fresh, new from the packaging SureFire SF123As?
You stored the A2, confirming that it was indeed fully locked out, in a cool, dry location out of direct sunlight?
Nobody else could ever have used it without your knowledge?

Once a CR123A battery has been used it's shelf-life is compromised. I'm pretty certain that is the case although I can't say where I know that from.

The A2 draining batteries is not a known issue. Occasionally people find the batteries in a flashlight have not given them the runtime they expect. It's not usually model or battery brand dependant AFAIK.

Size15's said:

Once a CR123A battery has been used it's shelf-life is compromised. I'm pretty certain that is the case although I can't say where I know that from.

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I've heard that mentioned around here, though CPF user selfbuilt did a test for this (see his CR123 and AA shootout thread from earlier this year), and he found no evidence to support this. Rather, his data indicate that CR123 self-discharge is unaffected by the amount the cell has been used. Granted, this is only one test, but I don't think I've seen test evidence elsewhere to contradict it.

Anyway, in regards to dudemar's A2, my guess would be either some battery issue (not recently manufactured cells, etc.), or it wasn't locked out and got accidentally activated at some point. Or possibly if the cells were from a less reputable manufacturer? (In my experience, for instance, Tenergy CR123's have only provided barely more than half the capacity of brands like SureFire and Panasonic.)

NE450no2,

I will attempt to answer your question to the best of my ability. Keep in mind that there is subjectivity in this. First whereas the A2 is more along the Executive series in size, the U2 is massive, being far larger than any of my SF 6v lights, and I have a lot. The U2 is also relatively heavy. As for use, the U2 is the easier of the two. I seem to use it either on it's lowest or highest setting. The U2's LED is very yellow in color, whereas the A2 is much more natural (LED) in color and gives far better color rendition. One thing I do not really like about the A2 is the relative weakness of the incan. It is 50 lumens, as compared to the 60 that a P60 emits, but the difference is significant. Maybe the small reflector combined with the intrusion of the LED's. With all of this being said, I like both lights, but the A2 is what goes with me every day.

Size15's said:

They were fresh, new from the packaging SureFire SF123As?
You stored the A2, confirming that it was indeed fully locked out, in a cool, dry location out of direct sunlight?
Nobody else could ever have used it without your knowledge?

Once a CR123A battery has been used it's shelf-life is compromised. I'm pretty certain that is the case although I can't say where I know that from.

The A2 draining batteries is not a known issue. Occasionally people find the batteries in a flashlight have not given them the runtime they expect. It's not usually model or battery brand dependant AFAIK.

Click to expand...

This has happened ever since I purchased the light (in 2004) and after I got a replacement TC by warranty (in 2006) because the lock-out feature no longer worked (if anything this is indicative of how often I used the lock-out feature). This happens irregardless of brand or freshness of the battery (including SF), and the only other brand I use is PentagonLight (which made great batteries).

This isn't the first light that had this happen to me. I have a Pila GL3 (old style) and a PL eL2 that ends up with dead batts if they sit too long.

I guess it's just better to leave the batteries out under long-term storage.

dudemar said:

This has happened ever since I purchased the light (in 2004) and after I got a replacement TC by warranty (in 2006) because the lock-out feature no longer worked (if anything this is indicative of how often I used the lock-out feature). This happens irregardless of brand or freshness of the battery (including SF), and the only other brand I use is PentagonLight (which made great batteries).

This isn't the first light that had this happen to me. I have a Pila GL3 (old style) and a PL eL2 that ends up with dead batts if they sit too long.

I guess it's just better to leave the batteries out under long-term storage.

Click to expand...

I don't suppose you'd be interested in doing an experiment? Specifically, take two sets of cells from the same batch (same brand, same manufacture date, fresh from package, etc.). Put one set in the A2, activate it on high for a given period of time (maybe ten minutes?), then take out those batteries, and set them aside, leaving them untouched for six months. Then, with the second set, put them in the A2, run it for exactly the same amount of time on high as with the first set of cells, but this time keep them in the flashlight, and set the light aside for the six months. At the end of the six months, run both sets of batteries dry on high on the A2, measuring how long each lasts. Assuming they're good cells, then this should tell you whether the power drain is a CR123 issue, or something specific to your A2.

Of course, such a test would put your A2 out of commission for six months, which may not be possible depending on your lighting needs. But if your use of the A2 is pretty infrequent, then even just swapping out the "test" batteries for "general use" batteries on the occasions when you need the light, the test should still be useful, so long as the "test" batteries go back in as soon as you're done using the A2.

Granted, this wouldn't be the most reliable test setup, but if it yields a significant difference between the batteries left in the flashlight vs. the ones stored separately, then you know it's something to do with the light. And on the other hand, if the cells perform the same (and exhibit the same reduced capacity you saw before), then maybe the issue of CR123 self-discharge after partial depletion deserves further scrutiny?

jw2n

Thanks for your reply, and I under stand your answer 100%.

I was considering the U2 as not an EDC but as a USER when hunting/camping, because of its low/high capability, keeping the A2 in reserve as an EDC with full batteries. [With my E1e as an EDC as always].

I have found the Regulated 50 lumens of the A2 to be perfect for "Personal" use when I need "some high", and the 3 lumen low to be easy on my night vision, bit bright enough for "navagation" in a tent,motel room or on a known trail.

Any light much brighter than the 50 lumens of the A2, are just to bright for Personal Use IMHO, and as much as I like the 6P type lights the fact that they have no "low", makes then not suitable for a Personal light for ME.

They [the 6P, G2, C2 etc.] are a great compact Tactical, and use at a distance working light IMHO.

Do you have an E2L and or an A2L and what do you think about them?

The only reason I am considering another SF light besides a third A2 is for the advantage of the longer runtime of an LED, as some of my trips are out in the bush, toolies, or into third or fourth world countries for fairly long periods of time.

Also let me add that I have never experienced any parasitic drain in any SF light.

Some of my Weapon lights have had the same batteries in them for YEARS.

jw2n

PS. it is your, and other USERS "subjectivity" about a light that is important to me.

You can study the "stats" all you want, but the true crux of the matter, is what the "Human" factor reveals.

Thanks again for your reply.

Size15's said:

Once a CR123A battery has been used it's shelf-life is compromised. I'm pretty certain that is the case although I can't say where I know that from.

Click to expand...

I've noticed this problem with high-drain flashlights, usually incandescent. Either the initial high drain compromises the shelf life, or else the partially used batteries are less forgiving of further high drain after they have been sitting for a long time.

I have not noticed a loss of capacity for moderate-drain LED lights. My 2007 Surefire E2L (Cree emitter, 45 lumens) lasted for over a year with intermittent use on its original set of batteries.

NE450No2,

I am not going to be the best person to ask about LED. I own several, but I am more of an incan/HID user (blasphemy). I use LED for close up and general lighting, and incan or HID for brilliant illum, or distance. I utilize them in a complimentory role. i.e. Zebralight H30 as a headlamp and general illum, and a M2 Turbo for the reach out and touch something light. I bought the A2 to see if a hybrid would work for me, and simpify my pack. I carry a small pack everyday and the two light arrangement is the type of set-up that works best for me. I am currently looking at the Jil Light eznite as a possible upgrade. You will notice I try to stick with a common batt type for EDC, nor do I carry rechargeables. This is what works best for me and I do not expect that it would be the same for someone else. I didnt answer your question, did I?

I don't own a U2, but I do own a few A2s...if they're in the house where room temp is 77F ambient you have no worries, now if its stored on the car where temperature regularly hits 90F ambient with an occasional high you will experience some degree of parasitic drain, but its not because of the light itself

This is one of the reasons why I like these forums. I am constantly learning new things. I did not know that high ambient temp affected lithium batteries.