Date: Sat, 06 Feb 1999 00:41:06 -0500 (EST)
From: Marty Goodman MD KC6YKC <MARTYGOODMAN@delphi.com>
Subject: AA 1.5V Lithiums vs "123" 3 volt Lithiums
To: bikecurrent@cycling.org, randon@cycling.org, info@night-sun.com,
        cateyeusa@aol.com
Message-id: <01J7EKF2CJR69C2NQS@delphi.com>

I just had occasion to do some quick comparisons between two
easily-available primary (one time use / disposeable) Lithium batteries:
 
The Eveready AA 1.5 volt LiFeS battery
 
   and
 
The "123" style 3 volt photoflash battery (I'm not sure of it's
chemistry).  These batteries are a little wider in diameter than an AA
battery, and about 2/3 the length.
 
  Both of these type batteries are widely available at all Radio Shack
stores, and at all Home Depot stores (the latter has by far the best buy
on them).   The "123" photoflash battery is also available at many drug
stores.
 
Reading from Eveready's literature comparing the batteries when used in
a 3 seconds on, 9 seconds off intermittent operation (there were no
graphs for continuous duty use... that was the most continuous use of
those recorded in Eveready's comparisons in their literature) one learns
that a 6 volt battery consisting of 4 Eveready AA cells will operate a
given photoflash for 2000 cycles before voltage falls below 4 volts,
while a 6 volt battery consisting of two "123" type cells will operate
the same flash for 1000 cycles before voltage falls below 4 volts.
 
   From this I conclude that 2 AA Eveready LiFeS batteries have roughly
TWICE the energy capacity of 1  "123" style 3 volt lithium photoflash
battery (in that application).
 
   In terms of WEIGHT, two AA LiFeS batteries weigh just a bit less than
twice as much as one "123" cell.  Meaning the two cells are very similar
in power capacity per unit weight, tho the Eveready AA has a very slight
advantage there.
 
   In terms of ECONOMY, four AA Eveready LiFeS batteries cost about
$8.50 at Home Depot (rather more at REI or Radio Shack), where two "123"
cells cost $9.50 at Home Depot.   But 4 LiFeS AA's have twice the watt
hours of 2 "123" cells, so in terms of ECONOMICS, the Eveready AA's are
more than TWICE as economical.
 
   In terms of VOLUME, one "123" cell has roughly the same volume...
maybe a bit less... than a single Eveready AA cell.  And each cell has
roughly the same power capacity (watt hours).  So they are essentially
the same in terms of watt hours per unit volume.
 
 
   I hope this has proven of interest to tinkers making up home brew
high end systems using Willie's LVR's and low power lighting for Randon
applications.
 
   ---marty