On Mon, 2005-12-26 at 17:14 -0800, William Chops Westfield wrote:
> On Dec 26, 2005, at 7:42 AM, David VanHorn wrote:
> 
> > Poor Nicad is left in the dust
> 
> As I take apart modern laptop battery packs, I am amazed by the
> amount and complexity of electronics they contain.  And I always
> wonder what sort of performance could have been pulled from older
> technologies (like NiCd, or even Lead-acid) if a similar amount
> of 'smart electronics' had been dedicated to 'managing' THEM...

Not much. Lead acid and NiCad are comparatively both very forgiving of
charge curves, overcharging, and even deep cycling (to an extent).

The majority of electronics in modern packs are there for safety reasons
and to protect the battery from deep discharge. 

NiCads and lead acid were quite safe, they could take a huge amount of
abuse and usually get ticking (of course, push any battery too far and
bad things will happen, it's just the bar was pretty high before the bad
things started happening). 

Li-ion batteries can be VERY dangerous from even the most "benign" types
of things. Overcharging or charging them too fast can be VERY dangerous
(think flames...). Discharging them too far can irreversibly destroy the
battery.

Aside from safety, putting more of the charging circuitry into the pack
itself lets manufacturers keep their devices slightly more generic,
passing some of the cost over to the battery, allowing cheaper "trim"
levels (like in cars).

The only real distressing thing to me has been the complete loss of ANY
standardization of batteries. It would really be nice if laptop
batteries were standardized. The batteries would be FAR cheaper.

TTYL

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