[Lowfer] Lithium packs (Was: A power supply head scratcher)

[riese-k3djc at juno.com]

Supposedly, the best storage lifetime occurs when they are kept cold, 
but somewhat discharged.  For most LiIon chemistries, this is probably 
in the 3.3-3.6 volt region.  Supposedly putting semi-discharged LiIons 
in deep freeze will mostly stop that "clock."  I obtained some surplus 
"new" LiIon cells (raw cells - with no attached circuitry) several years 
ago and charged them to about 3.5 volts/cell, wrapped them in plastic 
and kept them in the deep freeze.  When I have pulled them out for a 
project (to "re-cell" a camcorder pack or something like that) and run a 
load test (using my West Mountain Radio CBA-II) to determine their 
health, they seem to be maintaining their capacity - even though they 
are now getting to be quite old, so the "freeze thing" seems to work.  
Occasionally, I'll check the cells' voltages and top-off (after they 
return to room temperature!) those that have dropped below 3 volts or so 
due to self-discharge.
 

I have some Nicads from the phone factory where I retired 10 yr ago
several years before that I borrowed some and read that a full charge and
freezing them
will keep them and it does. I still have some that are good and show
nominal term voltage
while frozen

Bob K3DJC
____________________________________________________________
Penny Stock Jumping 2000%
Sign up to the #1 voted penny stock newsletter for free today!
http://thirdpartyoffers.juno.com/TGL3141/4bcd08a017360236f1m03vuc