On Sun, 10 Feb 2002 23:49:45 -0500, "Dirk J. Bakker" wrote:
>nobody@home.nohow wrote:
>>On Tue, 5 Feb 2002 01:44:30 +1100, "Hughy"
>> wrote:

>>>Lithium Ion batteries can explode if a charge is applied when the
>>>battery has fallen below a certain voltage. For this reason protection
>>>is applied to the battery which causes it to go open circuit once it
>>>falls to a critical level.
>>>
>>>A greater problem however is the tendency of Lithium Ion batteries to
>>>fail with a full charge - especially after around one to two months has
>>>elapsed with no discharge. Canon recommend their Li Ions be totally
>>>discharged before storage.

>>Is it just me, or is there a fundemantal inconsistency in the above?
>>If the battery is going to explode when you try to charge it after its
>>voltage has fallen below a certain level, why on earth would you want
>>to completely discharge it? Or is this a nefarious plot on Canons'
>>part to injure those poor souls who follow their advice?

>It is just the way you're reading it. IF the batteries, in fact, have a
>"built-in" protection to being discharged to the point of becoming
>dangerous, then Canon's advise to be discharged [to the degree that they
>can be] is not inconsistent.
>
>What Canon advises is:
>
>"Storing the battery pack
>• If you do not use a battery pack for a period of more than a few
>months any remaining charge may cause
>damage to the battery pack, and reduce usage time. To prevent damage
>therefore, aim to use a battery
>pack's complete charge before storage."
>
>Why do you think doing this is going to invalidate the safeguards?

Don't these things "self-discharge" in time, and if you start
with a low charge, might there be an eventual further
discharge sufficient to "kill" the battery? Best I can
come up with for storage: charge the batteries fully,
then every month or two stick the wire ends of 10-ohm,
10-watt resistors into the terminals and discharge the
batteries a couple of minutes (being careful not to forget
and accidentally fully discharge the batteries!!!). When
the charge gets low (after several months, checked on a
camcorder), recharge... BTW, I have for years stored
many Sony Info-lithium batteries fully charged without
problems, but the info above scared me into this new
procedure... - maybe I should abandon it and return to
what has worked fine in the past, which also appears to
be less accident-prone? ;-) The averages may work out that
I lose fewer batteries simply storing them fully-charged...
BTW, I now do use the 10-ohm resistor on a battery for
a few minutes that has been stored (fully or partially
discharged before storage) before charging it for use
(making sure first that it still has some charge on it...).