EV Digest 3967
Topics covered in this issue include:
1) Re: Heater/defroster ideas?
by Doug Weathers <[EMAIL PROTECTED]>
2) Re: Heater/defroster ideas?
by Doug Weathers <[EMAIL PROTECTED]>
3) Re: GVWR, was: The 200sx is alive!!
by "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
4) Re: Heater/defroster ideas?
by "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
5) Re: The Amazing Little Hawkers That Refuse to Die!
by Lee Hart <[EMAIL PROTECTED]>
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On Friday, December 17, 2004, at 06:43 PM, M.G. wrote:
How about a chemical reaction that could be undone ( recharged ) at
the same time the batteries were being charged?
MikeG.
That's a really interesting idea. Something like sodium acetate, like
in those reusable heat packs?
http://www.9thtee.com/reheater.htm
Actually, I just found a nice page on other phase change materials for
heat storage:
http://www.eere.energy.gov/consumerinfo/factsheets/b103.html
It sounds like packaging is not yet fully worked out.
And this would be fairly heavy, too. I wonder if the extra complexity
and weight would be worth the savings in electricity (from not using
resistive heating from the traction pack) ?
--
Doug Weathers
Bend, OR, USA
http://learn-something.blogsite.org
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On Friday, December 17, 2004, at 11:06 PM, David Roden wrote:
On 17 Dec 2004 at 12:49, Tim Clevenger wrote:
Do hair dryers self-limit when the fan dies?
Unfortunately, no. I know this from experience.
Hmm, the hair dryers I've used all had thermal fuses in them that
opened when the airflow stopped. Of course, after they cool down
(about 5 minutes, usually) the fuse resets and they heat up again.
If you didn't catch the problem soon, you'd drain your pack, but I
don't think you'd melt anything. David, could you tell us your sad
hairdryer story?
--
Doug Weathers
Bend, OR, USA
http://learn-something.blogsite.org
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Our RX-7 originally had 18 6 volt floodies in it. Not only did I have to
replace a rear wheel bearing, but the unibody now creaks, even with the
lighter YT pack!
>How many folks out there have exceeded this value for their car, with or
>without upgrading the suspension? Is there anyone who has had a "bad
>experience" from having done so?
>
>
> --chris
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Hmmm, I just converted a 10kW genny from gasoline to propane, to use as a
range extender while pulling a trailer, and I have a propane heater in the
pop-up camper...
>I could suggest investigating a propane furnace something like a camp
>trailer or motorhome. They are quieter than the gasoline heater I had, but
>not as quiet as a ceramic heater in the original defroster ducting.
>
>Joe Smalley
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John Wayland wrote (and wrote, and wrote...):
> A while back, when responding to modular charger and battery
> questions, Lee Hart wrote the following chart:
>
> cost power range life
> ---- ----- ----- ----
> Hawker, Optima AGMs high high low low
> Concorde AGMs medium medium medium medium
> Flooded golf cart low low high high
>
> With all the well deserved respect to my friend, I had to laugh at
> this...
John, thank you for providing so many good data points to support my
little chart. Everything you said fits in with it perfectly! :-)
Most of your anecdotes provide excellent examples of the Optimas and
Hawkers high peak power capabilities -- just as I said. And, there were
no examples of long range EVs with these batteries -- as I said. (There
are some examples, though. One is Alan Cocconi's Honda Civic with an
amazing 26 Optimas jammed in, though he also used a generator trailer to
extend his range, so it wasn't all due to the batteries).
While you've had good *calendar* life with these batteries, I'll bet
your *cycle* life is pretty low. You don't use these vehicles every day;
in fact, if they have lasted 7 years, I'd guess you cycle them a couple
times a month on average. That's 7 years x 12 months x 2 cycles/month =
168 cycles. In this kind of service, your batteries *will* last many
years. They will die of old age or some other abuse rather than from
cycle life.
Have you actually done an amphour capacity test on any of these
batteries? I'm curious to know what they actually deliver. Many of the
applications you mentioned are not at all stressfuly from an amphour
perspective -- they just required high peak power for brief periods of
time.
> The only time golf car batteries give the high range Lee lists, is
> when they are a part of a HUGE battery pack... Red Beastie
I should have labelled my chart "Cycle Life" instead of just "Life".
What I intended to say was that you'd get more total miles out of a pack
of floodeds, and less out of Hawker or Optima typ AGMs.
You supported this with your comments on the golf cart batteries in the
Red Beastie. They provided far more range than your Hawker or
Optima-powered EVs. I'd guess that its pack delivered 2-3 times more
miles than your Optima-powered Blue Meany.
And, you are correct that you need a bigger, heavier pack to get a given
amount of power from flooded golf cart batteries. Their power capability
is low, as shown in my chart. I'd guess that for a given amount of peak
power, you need twice the weight in flooded batteries to match the best
AGMs.
If you build an EV with flooded batteries, and then try to pull huge
currents from them, they don't abruptly die. But, you *will* drastically
shorten their life. So, there is a trade-off point -- a current above
which you'd get better life and lower cost-per-mile with AGMs.
I'd say the rule of thumb is to look at your average discharge current.
An average current of 1C means you drive your EV for about 1 hour before
the pack is exhausted. If it is lower than the battery's 1C rate,
floodeds will work better. If it is higher than the 1C rate, AGMs will
work better.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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