Hi HarryN,
Thanks for the interesting comments:
[ QUOTE ]
There are tradeoffs to each selection of battery size for a light. I am not sure that I have enough data yet to say that AA or 123s are better for extreme temperature conditions, as so far, Silverfox has only tested down to 0 F, which is not really "extreme", just "cold" (I have lived places where we were really happy for days that went above 0 F)
[/ QUOTE ]
Quite true. We need more testing. I really want to see Li/MnO2 123s tested at -20C and Energier and BatteryStation Li/FeS2 AAs tested at 0C and -20C. The Energizer Li AA data sheet does have achart showing that they deliver "70% Typical Service" at -20C as compared to +20C.
[ QUOTE ]
I remain conservative about whether or not the typical high end flashlights sold with fancy electronics and boost converters will work on a really cold day, especially if run off of a cell pack which is only starting out at 1.5V on a warm day.
At this point, I have taken the path with my lights that V battery must be > LED Vf + 1 - 2 volts at 0 F. (or colder) or it is potentially not rugged enough. From a battery pack perspective, this means at least 2 x 123, 2 x CR2 or 3-4 x AA. 4 X AA can be kind of large for a small light.
[/ QUOTE ]
I use the UK4AA handlight. This form factor with 4AA cells is very compact. It fits in pant pockets and even shirt pockets. One drawback to this form is that since it is not cylindrical it does not lend itself to being fabricated from aluminum. Currently I use the UK4AA with a 1W LED and also with the 4 watt incandescent. I would like to see it with a 5 watt LED module and a 10 watt incandescent, 4 Lithium AA cells are capable of supporting these loads, the problem is that the plastic body might not be a good enough sink for the waste heat.
[ QUOTE ]
This may be just plain wrong, and power wasteful, but there are few things worse than being stuck on a road when it is (-35 F) and your flashlight does not work. When it is that cold, you REALLY need your stuff to work.
[/ QUOTE ]
Quite so but I also want my GPS, radio and headlamp to work and they all operate on AA cells. A flashlight that uses 123 cells means that I have to carry spares in my backpack just for it.
[ QUOTE ]
If I have some extra V bat and a resistor, it is virtually a given that it will start up. (blaspheme, I know). With the right setup and battery, it can also achieve reasonably flat light output and 75 - 80% of the power efficiency.
[/ QUOTE ]
I carry enough stuff in my backpack. I don't even like carrying spare batteries (123s) that are only good for one device.I think I will resist the tempation to carry resistors et. al.
Big_Ed:
[ QUOTE ]
Also, if a lithium AA isn't available, a standard alkaline AA will do just fine. You can't really say that about 123's.
[/ QUOTE ]
Yes, another big plus for Lithium AAs vs 123s.
Lynx_arc:
[ QUOTE ]
If you must have lithium for now it is a tossup as to which is best as until another vendor comes along eveready and batterystation are the only two playing the game as far as I know. At over $2 each unless batterystation keeps lower prices the around $1 123 cells may end up being cheaper later if somehow eveready manages to intimidate/sue batterystation out of the market.
[/ QUOTE ]
I remain optimistic that alternate Lithium AAs will remain on the market. From the testing that SilverFox has done you can see that the BatteryStation Lithium AAs perform differently from the Energizers; I hope this means that they are different enough that they don't infringe on the Energizer patents.