[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: (ET) New Member
On 3 Jul 2008 at 8:59, Michael S Briggs wrote:
> High internal resistance effectively translates into a high Peukert
> number, as more energy is lost over the internal resistance at high
> discharge rates (and high charge rates), and thus not available for
> use by the external circuit being powered.
Go out and mow your lawn. Now put your hand on a battery. Too hot to
touch? No. Warmer than ambient? Probably not. The ET simply does not
use
enough current for the small loss of golf car batteries to matter. It is
negligable.
Some engineers (btw, note well - I'm a EE dropout ;-) get excited by new
developments, especially when the developers hype them as the answer to
every problem. These engineers sometimes forget about the solutions which
have served them well for many years, and often end up using the new stuff
where it's not really a better answer. (For example, these days it seems
as
if everything has to have a microprocessor in it.)
Let me give you an end-user's (rather than an engineer's) example.
Some years ago I installed supplemental electric heat in a cool room of
our
house. I bought an electronic (non-programmable) thermostat to control
it.
It cost about twice as much as a mechanical thermo, but it promised
tighter
temperature control.
I replaced that thermostat twice in 3 years. The first time I tried
another
electronic thermo. When that failed too, I put in a $12 mechanical
thermostat. The mechanical thermo is still working fine 5 years later.
The
comfort is just as good as it was with the fancy electronic thermostat; at
least I can't feel the difference. Sometimes low-tech is the appropriate
solution.
I would also note that many ET owners feel this way about the GE control
vs.
electronic controller upgrades. The contactor controller may be "Apollo-
era," as one EE has called it, but it works well enough for them, and
(maybe
more importantly) they can work on it.
The main reason I like my Alltrax better than the GE contactor controller
is
that it gives me the finer control of speed, and I really like that for
manuvering round tight areas in my yard.
I also found that the old GE controller in my ET had frequent reliability
problems, no doubt mostly from age. I probably could have rebuilt it with
new components and gotten improved reliability. However, I thought it
would
be easier to drop in the Alltrax, and I wanted the smoother control anyway.
For me, an electronic controller is appropriate; for many other ETers, the
old tech contactor and resistor controller is appropriate.
To cut to the point -- please excuse me for saying so, but I think that
using lithium batteries for an ET is an inappropriate use of the
technology.
As I've detailed before, lithium batteries offer no significant
advantages
for the average ET user, Meanwhile, they run up the cost and complexity
markedly.
There are a few other issues I haven't mentioned before.
Lithium battery technology is not proven, and lithium is far less
plentiful
than lead. It's not clear that there's enough to mass-produce EVs using
lithium batteries for dozens of years.
Lithium is also geographically concentrated in strategically questionable
areas : I may have misunderstood, but from what I've read, China controls
most of the world's supply of lithium.
I don't know about lithium's ability to be recycled, but lead is certainly
proven in that matter. If the supply is limited, let's hope it's easy -
and
doesn't require a lot of energy - to recycle it!
Of course, just as I found enough reasons to convert to an electronic
controller, you've apparently found enough reasons to convert to lithium
batteries. Go for it! Keep us posted.
David Roden - Akron, Ohio, USA
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to the "etpost" address will not reach me. To send
me a private message, please use the address shown at the bottom
of this page : http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =