On Tue, 17 Sep 2002 11:41:15 -0700 John Wayland <[EMAIL PROTECTED]>
writes:
> Hello to All,
>
> Since I first proposed the electric Insight project, I've been
> cringing while reading some of Dave's remarks, and just
> can't hold back as I feel the need to step in with my
> perspective and corrections.
Sorry, John, but you are not the first person
to consider an Insight EV conversion. Nor, for
that matter, am I. An electric Insight with a
Solectria drivetrain was shown at EVS-17 in
Montreal back in October, 2000. It was
powered by an experimental high energy
density Zinc-Air battery.
> Dave Goldstein wrote:
>
> >What a great idea: Introducing "The Green Battery"
> >into the green Insight! I LOVE it! :)
>
> No! The idea is to use the affordable and likely to be available in
> the next month or so, Nickel Zinc batteries, not the far-too-
> expensive, far too finicky, far too elaborate NiMH batteries!
> I also believe, that even with a seemingly lower whr per kg
> energy density, the Nickel Zinc batteries in real life
> application, will take the car farther per charge than the
> same weight of NiMH batteries that have to be kept in
> their 'sweet spot' that greatly reduces the amount of energy
> one can reliably extract from these type of batteries.
The idea of an NiMH Insight was first raised on this
list by Michael Hurley on 09/10. My response about
the "Green Battery" -- NiMH's byline -- was directed to
his questions, not yours.
It was obvious that you have not seriously researched
NiMH, or else you would not be repeating old wives tales
about "sweet spots" and the amount of useful energy that
can be extracted. As a matter of fact, there is NO "sweet
spot" and NiMH batteries can be repeatedly deep discharged
with excellent cycle life -- better than 1,000 cycles.
I know something about this, having been a member
of the DOE/NREL Ad Hoc Advanced Battery Readiness
Working Group for that past 10 years, and I have been
involved with EVs and batteries of all types for more than
25 years.
There was never any doubt that you intended to go
with Nickel Zinc (NiZn) which, for a variety of reasons,
has not been a serious battery contender with the US
Advanced Battery Consortium (USABC) for many years.
I was trying to tell you in a gentlemanly way that you
are likely to be disappointed with NiZn, but, as they
say, "It's your nickel!"
> >Besides the cost issue, several major problems
> >must be addressed in trying to install *any* type
> >of traction battery pack in the Insight:
>
> I don't agree, and remember, I own an Insight and have had it torn
> apart more times than most folks....I know the car intimately!
>
> > 1.) Weight -- With a present curb weight of approx. 1,940
> lbs.....
>
> Dave, you're off a bit here. the car with AC, weighs in at 1887 lbs.
I repeated the curb number quoted on this list by Martin
Jackson on 09/10, even though my number for the original
Insight was also 1,887 lbs (with A/C). I assumed that the
newer models had gained weight. But I will give you back
the 53 lbs.
> >this car will have to lose ~350 lbs (160 kg) to handle a 750 lb
> (340 kg) battery pack, in order to reach John Wayland's 2,350
> lb target. This may be a challenge . . .
> Since you were off by more than 50 lbs., and using your logic, the
> car now has to lose just 300 lbs. You're also forgetting other weighted
> items that add up fast, like the car's exhaust system that has both
> a muffler and a catalytic converter...maybe 40 lbs.? . . .
>....I've been involved with probably more than 100 EV projects, and
> I am usually right on with my ideas and estimates.
> Just to make sure this issue of weight is mute, remember that
> there's the engine radiator and cooling fans, many black boxes
> and their mounting brackets, heavy cabling, the gas tank
> and its brackets, etc.
I did not say that it was impossible to meet a 2,350 lb
weight target, just a "challenge". The car has already been
extensively weight lightened by Honda.
I would not eliminate at least a small 12 volt auxiliary
battery. What happens if your DC-DC fails or blows a
fuse on the freeway at night? No lights, emergency
flashers, etc. Also, where will you put the charger
and how much will that weigh? How about the battery
boxes, vacuum pump assembly, motor, adaptor and
controller weights?
> >2.) Battery Weight: If you wanted to use the
> > 85 ah EV1 NiMH batteries, this would
> > effectively limit you to 250 volts (19 > modules @ 13.2
> volts, @18 kg = 750 lbs
> > 19.3 kWh of battery. In a
> > 2,350 lb car with good aero, that should
> > deliver better than 100 miles of range!
>
> Again, diss the NiMH idea, and go with simple and so far as
> demonstrated in Sheer's car, very strong Nickel Zinc batteries.
Wrong conclusion, John! Neither the large EV1 NiMH
modules NOR the NiZn's will give you high enough voltage
(300+) to do an efficient AC conversions, due to weight and
space limitations. HOWEVER, as I added in a later post,
smaller 50 Ah NiMHs WILL do the job, coming in at 300+
volts within the 750 lb weight limit, while delivering ~100
mile range and excellent cycle life.
> >** Note to Victor: Would 250 volts be
> > sufficient for your 1PV5105WS12 AC motor system?
>
> Victor says yes, but worries over a lower efficiency level...I do
> not, but I'll go into this later.
Victor indicated a strong preference for 300+ volts to
do the job properly. There is no doubt that you can
build a lower voltage, lower efficiency AC system, as
I think Victor would agree, but why would you WANT to?
>
> > 3.) Volume: This is really tricky. 19 EV1 NiMH's would
> > occupy ~ 5 cubic feet! That's 141 liters or approx. the
> > size of a 37 gallon (U.S.) tank! Could this *possibly* be
> > shoehorned into an Insight?! Frankly, I doubt it.
>
> Again.....diss the NiMH idea, and go with simple and so far as
> demonstrated in Sheer's car, very strong Nickel Zinc batteries.
> But, just to beat this down, even these batteries would fit. What
> I don't understand here, is why am I being challenged on my
> knowledge of a car I own? I've stated that batteries will fit easily...
> they will! Dave says, "Frankly, I doubt it", but he does not own
> an Insight, and has not had the IMA chamber torn apart as I
> have, has not had the entire rear of the car torn down, as I have.
> Under the hatch floor of the Insight, is a cavernous area, far bigger
> than needed for Honda's IMA stuff. It is 9 inches deep at the
> shallowest parts, very wide right up to the car's walls, and extends
> all the way to the rear bulkhead. I figured on 720 lbs. of batteries,
> 20 of the Optima sized Nickel Zincs, but many more could actually
> fit in there! Please, drop this batteries-not-fitting thing, you're
wrong!
Chill, John! No one, least of all me, is challenging you on
your knowledge of the car. This is simply about *how many*
batteries you can squeeze in there to get 300+ volts and
stay within the GVW, and even 20 NiZn's (240 volts) can't
do this. 26 higher density 50 Ah NiMH's CAN do it, however,
and deliver better range and battery life. So long as you are
willing to sacrifice voltage, efficiency, range and battery life,
then you have defined what is important to *you.* But I
don't think that will fly with the EV1 crowd, which is one of
the related discussions on this list.
> You're not taking into account, the way NiMH batteries
> have to be kept in their sweet spot, which reduces the
> actual delivered power they can put out. Nickel Zinc isn't
> as picky, thus more of their power can be used.
>
ALL batteries lose power as the capacity drops.
Ovonic publishes a curve showing "Specific Power
vs. Depth of Discharge" on their Web site which
looks pretty good to me. There are no "sweet
spots." I have yet to see a similar curve published
for the NiZns that you proposing. Do you have one?
> > And the expected battery life of NiZn in a heavy-
> > duty EV application is still an open question.
>
> On this, we agree. But....so far as we're seeing out west here
> with Sheer's car, the batteries do everything the company touts
> they will do, in fact, they are delivering even more than their
> rated capacity. When was the last time you saw a battery
> give more than the battery hype dudes said they would?
> Because Evercell seems to be on the conservative side, I
> tend to believe them about the cycle life . . ..
I think that could be a mistake. But so long as you are
willing to spend the money to find out, I encourage you to
go with this.
There is more than one way to build an EV and every
approach requires certain compromises to be made.
So long as you have defined what is most important
to you and what compromises you are willing to accept,
then no one can say that you are wrong.
Beyond that, I am not going to waste any more
bandwith arguing design philosophies. I will be
on travel for the next 10 days, and will be unable
to respond to additional comments until I return.
Good luck!
Regards,
Dave Goldstein
President, EVA/DC and
Program Development Associates
Gaithersburg, MD
