D
Don Klipstein
- Jan 1, 1970
- 0
I haven't bothered to look into the numerous consumer alert-type stories
that have been on the TV news, but there have been quite a few regarding
laptop and cell phone batteries starting fires, sometimes in pockets,
briefcases or luggage.
All the stories I ever heard had to do with lithium ion, which is
fussier (extreme intolerance of overcharging) and involves more reactive
chemicals. In that past year, I have been hearing a lot fewer horror
stories.
It's been suggested/discussed here in RCM before, that in general, the best
battery charging is slow charging.. both in terms of quality/level of
battery output and long battery life.
NiCd and NiMH is easily overcharged by slow charging. NiCd usually
tolerates slow-charge overcharge well, with a slight voltage depression
that can generally be fixed by full discharge followed by full charge
without overcharging. NiMH appears to me less tolerant of overcharging,
and prefers fast chargers because faster charging enables better detection
of full charge. Smart chargers for NiCd and NiMH tend to have charge
times 4 hours or less.
The instant gratification or demand for instantaneous results (commercial
uses) of power tool, or critical use batteries have contributed to the
availability of rapid-charging battery chemistry and construction design
technology.
Forcing rapid chemical changes can't be good for long battery life, and
probably reduces the useful charge output, in most cases (for most types of
batteries).
- Don Klipstein ([email protected])