My most reliable EDC light has been the small photon light which has been on my keychain for well over 15 years and is still going strong (I'm not even sure I've ever change batteries but it is hardly ever used.)

I have since added an Quark Mini AA which is LESS reliable. Known issues:
1. uses AA. If I keep alkalines in it, the AA cell can leak and cause problems.
2. the head is screwed in and ISthe switch. The head is then loose and can fall off.
3. the head sometimes tightens up and I unknowingly end up with a dead AA.

The solution to the first one is to switch to lithium AA.

The solution to 2&3 is harder to figure out. Possible solutions:

1. keep things as they are. The head and the AA fall off inside my hip pocket.
2. tighten the head with the AA backwards or with a small bit of electrical tape.

Neither solution is satisfactory. I will eventually loose the head and fumbling around in the dark trying to turn on my light is not my idea of fun.

I am considering switching EDC single AA lights. I am considering a zebralight SC52w (if it ever comes off backorder).

Any other options (different single AA light) or ideas (change the way I carry the current light)?

I have been using a Fenix LD01 (AAA) quite satisfactorily for about three years. It too twists to light, but the head has not come off unintentionally. AA equivalents are available from Fenix et al. One good possibility is the Gerber Ultra Infiniti - I have several variations of that model and it is very reliable - just a bit too large for my keyring, however, but rock solid and dependable.

I'll bet if you took all the available single AA lights and laid them end to end, they would reach to the moon and back.

Don't ever use alkalines in anything you value. Either lithium or rechargeables are the way to go - no leaks and much cheaper in the long run, as well.

Using a thin case/holster would most likely address #2 and #3. Depending on how unobtrusive you want it, you may have to search around a bit. Many are padded a bit, which adds some bulk.

Or maybe get the holster and belt carry it, although some people may not want to look like they're carrying a folding knife on their belt.

Oh, hehe, I forgot my own personal carry method. A little while back, I developed a hole in my front pocket that I didn't notice and I lost my Fenix and Space Pen through that little hole. So I bought a small pouch (you could call it a coin pounch) that zips shut. I put my Fisher Space Pen, Fenix 1AAA light, and Leatherman Micra in there. Keeps everything together and a bonus is less wear and tear on my pockets! I think that should keep a flashlight from twisting in your pocket.

I'm surprised that the head on the Quark Mini can fall off simply from being in the off position. Or do you mean the head continues twisting in the pocket and THEN falls off? I have never had a twist-head light twist apart or turn on in my pocket before. Maybe by wiping off as much of the lube as possible from the threads, you can avoid that fate.

Twist switches do have their advantages. They are smaller, simpler and less prone to failure than click switches. In my own personal experience, the main problem I've had just once or twice is unintentionally over-tightening the head on lights that don't use spring contacts (these are typically compact 1AAA or 1AA lights). Sort of crushed the electronics in the head, although the lights still functioned.

True, KISS makes it more reliable. This may be an overwhelming feature that I can not ignore.

In my case, I keep it on a lanyard (along with a few other items). The package of stuff is in my hip pocket. I suppose when I sit up and down, the head continues to twist (on and off) from the initial off position. Sometimes it turns itself on (and I have a dead battery). Sometimes it twists enough that the head falls into my pocket along with the battery. When I pull out the lanyard, I have to fish in my hip pocket for the battery and head.

+1 on Fenix - I have a Fenix E01- no issues in 8 years.

Lithium only -- lighter weight, no leaking, hold charge forever.

I too have a Quark AA mini and have never had the head loosen on its own and definitely never enough for the head to separate from the body. I use a lithium primary or NiMH rechargeable battery.

Same here. Any flashlight with a metal battery tube carries lithium primaries. I have an E01 on a small split ring along with a LM Squirt PS4 and a screen wipe. I got it after a losing my Photon Freedom off of my keyring (crappy lobster claw).

There are two solutions for #2 and #3 that come to mind. The first is carry it in a case. Some of the guys over on EDCforums use MaxPed Micro Pocket Organizers and Notebook Covers to carry all their EDC gear.

http://edcforums.com/threads/edc-pocket-organizer-pics-part-2.101227/

I use a 3x5 notebook cover loaded with 50 sheet Ampad 20-208 pads. With only the pad, it's comfortable for hip pocket carry. When loaded with a light, knife, writing pad, business cards, etc, it's thick enough to require front pocket carry.

Second, go to a tail cap click switch like the 1xAAA Streamlight Microstream or 1xAA Fenix E12?

I have been using Fenix LD15 (AA lithium battery) for a few years. The screw switch is tight and turns only if you deliberately turn it. The LD15 is in the category of gear that I don't think about failing.

If I don't mind carrying something at least two times bigger, I carry a Fenix LD10, which is also boringly reliable. It has more throw and more features than the LD15, and has a push-button.

I carry an ARC AAA Premium.It is AAA but I get elevin hours of full light with a new battery.It carries in the pocket well and the head turns a little stiff.I will also second Hikermor on Fenix products and Gerber Infinity.Have three Infinities (car,coat and work)and had them for YEARS with no issues.The Fenix I have is an E01.Very similar to a ARC AAA and around half the cost.The ARC AAA is made in America and the Fenix in China if that matters....

BOATMAN
John

In a single AA flashlight, check out the FourSevens Quark Pro QPA. It's big for a single AA light, but the output has 0.2 lumens at the low end and 130 lumens at the high end with 5, 26 and 102 lumens in between.

BTW, since FourSevens has a 120 month warranty, why not contact them and see about that loose head on the AA mini.

I love my tiny Fenix E11. Battery lasts forever and the light is ultra bright on high mode. Low mode is great, too. Now it's been upgraded to the E12 with 3 modes. At around $30 you can't go wrong. It's my left front pocket EDC.

Another +1 for the Fenix lights.

My current EDC is a PD35 an LD01 (AAA). I decided that I needed a LOT more throw for the primary light last Fall. The PD35 was an upgrade for a LD20 which was an upgrade for a L1D/L2D/P2D set. The last three used either 2AA, 1AA, or a 123a battery with the same head.

I switched from a Fenix E01 to an E05 last year with AAA lithium... to tighten the head lamp assembly, a turn or two of teflon tape... be sure to not get any tape between the contact points

I"m still running a little E01, no problems to date. If I wanted to EDC a larger AA light I'd have no qualms about picking up a Fenix.

I'll echo that; I've had the E01 as a part of my EDC for 5 years or so now without any problems (I don't even use fancy batteries ).

I am also a big Fenix E01 fan. I use lithium batteries and I use the flashlight multiple times a day. An Energizer lithium 9x type lasts me about a year. The 9x supposedly lasts 9 times as long as an alkaline battery.

The Fenix has an o-ring under the cap so it doesn't come loose on it's own--at least it has never happened to me.

When I first started carrying the Fenix, I thought I would only need it for emergencies, but you don't realize how handy it is until you always have one in your pocket.

For an EDC I would stick with a AAA flashlight as it is much smaller than a AA one.

I lost my last E01 to an alkaline battery that was not out of date. I have since replaced all alkaline batteries with either lithium primary or NiMH rechargeable batteries.

I've moved mostly to fauxtons; cheap and reliable. Keychain, briefcase, coat zipper pull.

I picked up a few of these as stand-by beater lights. They work with a single AA, or with a 14500 lithium battery. They have been decent so far. I gave one to a friend, who uses it as a back-up bicycle headlight, which is handy with its three modes (high, low, and strobe) and zoom.

It isn't the best quality in the world. I won't pretend it is. But rain won't kill it, and it's a push-button 200-300 lumens (depending on battery) that can live in the junk drawer, BoB, or glove box without investing in name brand flashlights.

http://www.amazon.com/gp/product/B006E0QAFY/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1

Oh: The image is a bit misleading. The light is short. Just be aware.

I picked up a bunch of those lights to give out during Christmas 2012. I got mine from DX.com for $7 each. Amazon's $3.60 is a good deal. They have a zoom feature, which is cool. Seriously, with the spotlight feature, you can see farther than you should with a cheap light like this. All the flashlights still work, but they are cheap beaters like you said.

I would not want to rely on a questionable quality flashlight during an emergency when your life and/or well-being might depend on it.

May be in the bargain category, but I've carried one of these daily for about 4 years, and never had a problem with it. I keep Lithium batteries in it.

http://www.energizer.com/flashlights-lighting/flashlight/Pages/tactical-metal-1aa-1-watt-light.aspx

Recently bought the new version that has 85 lumens and like it as well.