[Elecraft] OT sort of. Charging Lithium Ion batteries

[Barry]

I've been driving a Tesla for almost 5 years and it runs on Lithium
batteries.  I've read some of the literature on Li battery use and chemistry
over the years from Tesla and elsewhere, including Jeffrey Dahn, PhD, of
Dalhousie University, who is the world expert on the subject.  Google his
name and you'll find a number of papers he's written.

The recommendation, for best life, is keep the charge between 20-80%.  If
storing for a while without use, 50% charge is best.  Tesla recommends only
charging to 100% immediately before starting a trip.  The biggest killer for
Li batteries is leaving them at 100% charge in a high heat environment (over
100F).

My car has a 85 kWh battery (roughly 7000 individual cells) and had a range
of 270 miles when I bought it almost 5 years ago.  I have adhered to the
recommendations and now, with about 55K miles on it, the max charge is 262
miles.  So about a 3% degradation - not bad!

It's a real shame that most device manufacturers don't tell you any of this,
especially with the trend of making batteris in cell phones, laptops, etc.,
not user-replaceable.

Barry W2UP



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