On Tue, 24 Dec 2019 16:07:28 GMT, Pamela
wrote:

On 16:00 24 Dec 2019, Andy Burns wrote:

Pamela quoted:

a Li-ion battery cycled within 75%-25% SoC (blue) would fade to 74%
capacity after 14,000 cycles.

If this battery were charged to 85% with same depth-of-discharge
(green), the capacity would drop to 64% at 14,000 cycles,

and with a 100% charge with same DoD [depth of discharge] (black), the
capacity would drop to 48%.

Assuming a charge cycle per day, I probably wouldn't care whether a
battery had 74%, 64% or 48% capacity left after 14 years ...

As mobile phone users know only too well:

For unknown reasons, real-life expectancy tends to be lower than in
simulated modeling. Environmental conditions, not cycling alone, govern
the longevity of lithium-ion batteries.

Well, most of my batteries have exceeded expectation (one lasting over
five years). I generally let the phone become quite well discharged
before putting it on charge. I am not convinced that an apparent full
discharge does any harm at all, as I assume the phone will shut down
before any harm comes to the battery.

There's a brisk trade in replacement batteries for phones only a few years
old which have lost a lot of capacity. Mine lost 10% capacity in 9 months
from new.

Is that abnormal? What do you believe the design life of a battery
is?