The 18650 battery, I think this pretty much comes under the proprietary or unique type of battery that I try and avoid. After having a bad
experience with Sony MiniDisc and their unique gumstick batteries that are hard to source and very expensive to replace I think i'd like to pass on this type.
18650s aren't proprietary at all -- they're the cell used in practically all Li-ion laptop batteries. Individually protected cells are a bit of a specialty item (laptop packs use unprotected cells with a single protection circuit for the whole pack; protected cells are pretty much only for flashlights), but they're still available from quite a few sources, and if anything supply is
increasing. Additionally, some 18650 lights, including the Solarforce L2, can also run on 2 CR123 or even RCR123 cells, so you're not even locked into 18650s should they become hard to obtain.
They offer the best energy/size ratio of any commonly available battery, and offer the simplicity and safety of single-cell with more power and energy than 2-cell 123 (Li-ion
or primary) setups. The technical advantages are both a good reason (IMHO) to invest in 18650 cells, chargers, and lights, in spite of whatever slight risk they may become unavailable, and also the reason they
won't become unavailable -- they're just too good to disappear from the market.
There are only 3 downsides to 18650s, IMO:
- No directly-compatible primaries for emergency use.
- Establishes minimum light size -- arguably a little big for headlamps and some people's notion of EDCable lights.
- Unfortunately, many 1x18650/2xCR123 lights under-perform on 18650 due to cheap drivers and high-Vf emitters. 18650-only lights and some combo lights are unaffected.
Considering that AA primaries (alkaline, but better Lithium) are available and mostly compatible, and that AA is plenty small for headlamps and such, I'd tend to recommend 18650 and AA as the most practical battery sizes, and CR123 (except possibly as a primary option for 18650 lights) as the one to avoid.
1) I am now leaning towards the PD30 as a multi purpose flashlight seems to have all the bells and whistles. I don't think its as rugged and
tactical looking as the Surefire E2DL though and doesn't have the strike bezel.
If you like the PD30, you might also consider the 4sevens Quark 123², also runs on 2xCR123 (primary or li-ion), has a wider selection of modes, and basically similar UI. Substantial mechanical improvements, IMO (clip, knurling, etc.). The Quarks are new, and the first batch just shipped out today, so there should be some reviews online in a few days.
Important detail: Quarks are rated by actual light output out the front (OTF) of the flashlight, but Fenixes are rated by light output from the LED, only about 70% of which makes it OTF. So while the Quark 123²'s high is rated 190lm, this should actually be slightly brighter than the PD30's rated 220lm. Again, look for head-to-head beamshots in a few days; I'm sure some review will pair these obvious competitors.
2) Need to find a good 2AA led flashlight I'd prefer multi modes but ideally I'd like to have a low power mode with just 5 lumens that gives
you upto 100 hours of runtime, then a regular mode maybe 100 lumens for perhaps 10 hours runtime.
Not possible, really. AAs get 2Ah * 1.2V = 2.4Wh, 2 AA is 5Wh, getting 1000 lumen hours would require 200 lm/W. The best you'll get from 2AA is around 3 hours at 100lm.
I'm not sure what to make of your "I'd prefer ... ideally I'd like ..." construction; if you're thinking more modes is better, as long as 2 of them are at those levels, the LD20 or Quark AA² are obvious picks; the LD20 has 71h @ 9lm (about 6lm OTF), 5h @ 94lm (~67lm OTF), and 2h @ 180lm (~130lm OTF) , and the Quark has 5 days (120 h) @ 3.5lm, 5h @ 70lm, and 1.3h @ 170lm. If you meant that you'd prefer
only those two modes, with a good UI for switching between them, the L2T and the tactical version of the Quark AA² (due out in a couple weeks, IIRC) would make sense. The L2T is fixed at 32h@16lm (~11lm OTF)/2.4h@152lm (~110lm), but the tactical Quarks can be programmed to any two of the 7 modes, so you could go with either 70lm or 170lm high, and either tighten for high or loosen for high -- much more versatile, and maybe hits your low target closer...
