Kevin Sharpe ZCW wrote:
Sorry but I'm not sure why we are discussing "various consumer products"
on EVDL... I assumed your comments were related to cars... Is that
incorrect?
I was talking about the lithium cells I can actually buy and (hopefully)
use in my own EVs. I think of them as "commodity" cells because they are
mass produced, and sold even in single-piece quantities to anyone that
asks. Miracle batteries only described in press releases, or only
available to large auto manufacturers don't do me any good.
I assume you've seen the recent PIA battery study which shows how well
'commodity' cells are performing in Tesla cars;
http://www.pluginamerica.org/drivers-seat/battery-study-updates
This is excellent. Thanks for posting the link, Kevin.
This data is very promising. It shows that long life is possible, with
the batteries and BMS systems being used by the large manufacturers. My
point is that these batteries are quite different from the commodity
batteries that individuals can buy.
The special Panasonic nimh cells used in the Toyota RAV4-EV have lasted
12 years and 100k miles. It proves that this chemistry *can* last. But
it doesn't mean that commodity nimh cells from Radio Shack will last
anywhere near that long.
The special 18650 lithium cells that Tesla uses have lasted 5 years and
100k miles so far. This proves the potential for this chemistry, too.
But it doesn't mean that generic laptop cells, or lithium cells with
other chemistries will do anywhere near as well.
I simply wanted to point out that people are buying commodity cells
based on cost, and expecting them to perform and last like the carefully
selected and meticulously managed cells in the big auto maker EVs. My
testing of various brands and types of inexpensive cells indicates that
this not likely to work.
Peri Hartman wrote:
> The other factor is, I'm fairly certain, that Tesla has a much better
> BMS than most laptops. Is that significant enough by itself?
I'm sure that plays a major factor. Most batteries don't die of old age;
they are MURDERED by one form of abuse or another.
--
Humanity is acquiring all the right technology for all the wrong
reasons. -- R. Buckminster Fuller
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
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