Re: [NTLK] Deep discharging Li-Ion ceels

From: Joost van de Griek (joost_at_jvdg.net)
Date: Sun May 11 2003 - 13:12:26 PDT


On 2003-05-11 20:30, Frank Gruendel wrote:

>> As for running a Li-ion cell down to nothing, there seems to be some
>> indications that this actually contributes to the effect described
>> above.
>
> This would be an understatement. Running Li-Ion cells down to nothing
> is one of the easiest and most reliable ways to kill them. Fortunately,
> this doesn't happen very often since they have next to no self-discharge
> and a built-in electronics normally prevents deep discharge.

I can attest to that. A Li-Ion Palm device will quite adequately destroy its
internal battery if left out of the cradle for an extended period of time.
Replacements are made of unobtanium, and expensive to boot.

Ouch.

The Li-Ion battery of my Sharp MiniDisc recorder was also left in the device
without AC power for about a year, but suffered no ill consequences. In
fact, it had some charge left in it, as it was stored fully charged.

> This electronics, however, is also the reason why you can't revive this type
> of cells by brute force as you can with NiCad and NiMH. Not that I would like
> to try, though. Li-Ion cells frequently develop an annoying desire to explode
> if they feel they aren't charged the way they are entitled to.

Li-Ion is a very user-friendly battery technology. Basically, you just feed
the battery a stable input voltage, and it'll charge until full. Pretty much
no charging logic necessary.

That would lead me to think that adapting a Newton to use and charge Li-Ions
shouldn't be excruciatingly difficult...

,xtG
.tsooJ

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Joost van de Griek
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