EV Digest 6270
Topics covered in this issue include:
1) Re: Battery theory
by Lee Hart <[EMAIL PROTECTED]>
2) Re: Circuit Breaker and Contactor
by "Brian M. Sutin" <[EMAIL PROTECTED]>
3) Re: Telsa EV on PBS Wired Science tonight!!,
by Lock Hughes <[EMAIL PROTECTED]>
4) Re: new EV business
by "Darin - MetroMPG.com" <[EMAIL PROTECTED]>
5) Low Cost Capacitor Sources
by "Bruce" <[EMAIL PROTECTED]>
6) Re: new EV business
by Jack Murray <[EMAIL PROTECTED]>
7) Re: Telsa EV on PBS Wired Science tonight!!,
by "Mike Phillips" <[EMAIL PROTECTED]>
8) Re: Joe Sixpack Geo: best controller SCR, Curtis or contactors?
(Or some combination)
by Lee Hart <[EMAIL PROTECTED]>
9) Re: new EV business
by Lee Hart <[EMAIL PROTECTED]>
10) Re: Exide orbitals
by Lee Hart <[EMAIL PROTECTED]>
11) Re: new EV business
by Lee Hart <[EMAIL PROTECTED]>
12) RE: Newbie Questions (Batteries)
by "Claudio Natoli" <[EMAIL PROTECTED]>
13) Re: [EV] Re: LogiSystems controller ?
by Robert Lemke <[EMAIL PROTECTED]>
14) Re: Low Cost Capacitor Sources
by Danny Miller <[EMAIL PROTECTED]>
15) RE: Driveshaft clearance
by Cor van de Water <[EMAIL PROTECTED]>
16) RE: Newbie questions (batteries) Cor - can you help this guy?
by Cor van de Water <[EMAIL PROTECTED]>
17) new EV business vehicle and PBS Tesla
by "jerryd" <[EMAIL PROTECTED]>
18) SCR Controllers: NOT!
by "Mark E. Hanson" <[EMAIL PROTECTED]>
19) Re: Electric for diesel swap in sailboat.
by "jerryd" <[EMAIL PROTECTED]>
20) Getting Subaru to do a Plug-in Hybrid
by Joseph Lado <[EMAIL PROTECTED]>
--- Begin Message ---
JS wrote:
What is the electrical capacitance of a PbA battery (in Farads)?
Is this 'surface charge'?
Surface charge is due to a thin layer of extra-concentrated electrolyte
and fresh plate material right at the surface of the plates, produced as
a consequence of charging. As soon as you stop charging, this layer
diffuses away so the voltage drops a little bit.
Batteries also have capacitance in the traditional sense; two plates
with large surface areas, separated by a thin layer of nonconducting
material. The capacitance can be quite large; various researchers have
measured it at 20-130 uF per square cm of plate area.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Yes, David, your hysteria is preventing Mr. Murray from winning his
Darwin Award. Please calm down.
Brian
Jack Murray writes:
> David, you sound hysterical not rude.
>
> The described setup is SAFER than using a contactor.
> A contactor CAN FAIL if it tries to break a runaway, wherease a
> a circuit breaker is designed to do exactly a safety shutoff.
> In any case, the car will have a manual shutoff, NEDRA requires it.
>
> Gas cars don't have shutdowns when you lift the accelerator pedal, I
> don't remember the safety recall on gas pedals for ICEs.
>
> Isn't uncommon for a DC controller to fail" please back that up with> some
> facts,
> Shari from electromotive has said in all their years only a single
> runaway, Otmar has said not a single runaway failure.
> But that isn't the real issue, if a controller fails how can it turn off
> a contactor?
>
> Jack
>
> David Roden wrote:
> > Hope you are using AC drive - or if not, that you never drive on public
> > roads.
> >
> > DC drive tends to fail full on, and your Rube Goldberg lashup may not
> > respond quickly or surely enough to keep you from taking out a few other
> > cars and trees, or a couple of pedestrians, if it does.
> >
> > At the risk of sounding rude, I'm going to say it. You are dealing with as
> > [...snip...]
--
Brian M. Sutin, Ph.D. Space System Engineering and Optical Design
Skewray Research/316 W Green St/Claremont CA 91711 USA/(909) 621-3122
--- End Message ---
--- Begin Message ---
Or on the web if you like:
http://www.pbs.org/kcet/wiredscience/player-conv-elon.html
tks
Lock
Toronto
Human-Electric Hybrid Pedestrian
--- jerryd <[EMAIL PROTECTED]> wrote:
>Hi All,
>It's on right now with the Telsa on late in the
> hour, 8pm EST.
> Jerry Dycus
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Roderick Wilde wrote:
One possibility if you want to be in the EV industry is to sell NEVs.
The ZENN car is just starting to take off here in the Seattle area
because it looks like a real car and that is because it is.
I would spin that idea differently: a potential market for commercial
conversions might be found in people who have *already* bought NEVs ...
and now have no "trade up path" (Xebra and Tesla notwithstanding).
NEV owners have already demonstrated acceptance of electric drive. But
it's electric drive with limitations: they are restricted to 25 mph top
speed, and can only drive on roads with low speed limits.
Surely by now there are NEV drivers who would jump at the chance to get
"off the leash" and into an EV that can go a little (or a lot) faster,
and has no restrictions on which roads it can use. These people are
already spending $10k US and more for 25 mph. How much would they pay
for a 50 mph "unrestricted" conversion with modern safety features if it
were marketed well?
And if I'm not mistaken, it's a not an insignificant market - GEM has
sold something like 30,000 vehicles in the US (though I don't know how
many of those are in commercial/institutional settings vs. privately
owned and used on public roads).
The low-buck, relatively low speed Geo conversion I'm working on will
essentially be an "unrestricted" NEV. (NEV's aren't yet legal in
Ontario, where I live.)
Darin
--- End Message ---
--- Begin Message ---
Even the 100F 16V car audio capacitors for $250 seem overpriced.
But still it would be interesting to experiment with a short range scooter
if you had 40 or so of them.
Probably not $10,000 worth of interesting though.
There must be cheaper sources for larger capacitors.
Where might one look for cheap, big capacitors?
What's the best deal per Farad?
Lee Hart wrote about the $250 3F 24V car audio capacitor:
> That's not a super cap; it's a plain old cheap electrolytic capacitor in
> a fancy overpriced package.
--- End Message ---
--- Begin Message ---
Gary,
I wrote some long versions, but decided not to send them.
The short version is I would not do what you suggest, convert new cars
to electric and sell them. Converted cars are never sold for anything
near their build cost particularly when built using premium parts, and
you can't compete with car companies big or small.
I would suggest you avoid any big capital expenses.
Come up with one or some components that are useful for an EV.
Build a low-budget car to test them, or better yet buy an existing EV.
This has been my approach, so far its been a great success, I've only
lost a small amount of money, mostly a LOT of time.
Hope that helps,
Jack
gary wrote:
Since this is probably the largest single collection of EV experts that
there is, and it has been a great list with lots of friendly advice and
good ideas, I'd like to see if I can get some feedback on an EV plan.
I am an electrical engineer (microprocessors, s/w, systems integration,
project management, etc.) and I recently left my job after 23 years to
move cross country with my wife who got a s/w job in San Antonio that
she couldn't refuse. She's paying the bills :<} so I have the rare
opportunity to try to start a business that I care about instead of
going back to a corporate desk. I was looking into solar and wind, but
got hooked on EV's. I know there's never been any money in saving the
environment but I don't need much to get by as long as I'm doing
something I like.
I started building a "rough" 3-wheeler as a test bed and I wanted to
design a few others that I have in mind. This takes money so I started
on a business plan for investors and will continue with that in
parallel. Part of that plan is to convert new cars as a short-term
product, to test systems, and to develop credibility for investors and
customers. Another goal is to design subsystems for EV's. I see plenty
of other people working on new vehicle design and subsystem design so
this is nothing new but hopefully the industry will get the attention it
deserves and will continue to grow.
We just signed on a $30K loan and I have a (refundable) deposit on a
2007 Honda Fit. I selected it based on cost, curb and gross weight,
utility, resale, etc. The Fit is 109 HP, 2432 curb, 3446 gross and $16K
(for "sport" model, base models are too scarce). Seems to be high
demand, and the new engine resale may be pretty good. Lot's of room,
safe, lightweight w/ ok gross, electric throttle and steering assist.
It's a very tight budget to offer a new EV for around $30K, especially
since it needs to be professionally done and maintenance-free, but I am
willing to work full-time to be able to sell the first one at cost.
This will get my foot in the door, test the market, and allow subsequent
conversions to be done much quicker with possibly a small profit. This
isn't intended to be a stand-alone money maker, just a path to learn and
become established. Worst case, I'll "get stuck" with a very nice EV
and continue working on designs.
I initially planned on the first one to be low-budget (DC/Pb) and
another to be high-end (AC/Li) but I'm considering AC/Pb right now.
That makes $30K almost impossible but I'm still trying to price all of
the options (I sent requests to ElectroAuto and MetricMind for
Solectria, Siemens and MES systems). I know Zillas are 6 months out and
I will order one anyway, and I just saw LogiSystems re-engineered Curtis
1221B's that I will look into (any feedback on them?). The goal is for
a daily commuter that will briskly accelerate to 65mph for highway use,
so range will be secondary. Both mine and my wife's daily drives are
well under 30 miles round trip and I have a 5 mile run at 70mph with
trucks on my bumper. I think that's reasonably average for a lot of
people, and battery upgrades would be available.
Non-EV'ers feedback is consistent - "Huh? That's stupid." What's the
feedback from within the community? Aside from why it may not work out,
I'd love to get ideas on component selection. I've read the whole AC vs
DC debate and battery tradeoff's but would still like to hear comments
on this particular application. I'm also open to partnering or helping
other efforts. Investors welcome!
Much appreciated. Thanks and Happy New EV's to everybody!
Gary Krysztopik
Z-Wheelz, LLC (website almost done - details of conversion will be
documented)
gkrysztopik at satx.rr.com
--- End Message ---
--- Begin Message ---
Very cool!
Mike
--- In [EMAIL PROTECTED], Lock Hughes <[EMAIL PROTECTED]> wrote:
>
> Or on the web if you like:
> http://www.pbs.org/kcet/wiredscience/player-conv-elon.html
>
> tks
> Lock
> Toronto
> Human-Electric Hybrid Pedestrian
>
> --- jerryd <[EMAIL PROTECTED]> wrote:
> >Hi All,
> >It's on right now with the Telsa on late in the
> > hour, 8pm EST.
> > Jerry Dycus
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
--- End Message ---
--- Begin Message ---
Another way to attack the ripple problem is to add inductance to the
motor loop.
Peter VanDerWal wrote:
I don't think that will work. It will reduce ripple on the motor
side of the controller, but won't effect the battery side.
The situation is more complicated. "Modern" PWM controllers (Curtis,
Zilla, etc.) use the most primitive converter topology -- a buck
converter. This topology has one transistor, one diode, one capacitor,
and one inductor. (OK, there are usually many transistors and diodes in
parallel acting as one big one, and the capacitor is mostly the battery,
and the inductor is in the motor; but the principle is the same).
But there are many more advanced topologies. SCR controllers were around
long enough that the later ones had evolved to use these more advanced
topologies. They often used soft switching, to avoid the abrupt "hard"
on/off switching to improve efficiency. They had internal inductors so
they didn't depend on the motor inductance. There were often 2 or 3
phases, where 2 or 3 (or more) SCRs took turns carrying current in
different parts of the cycle.
As a result, the input and output currents are not simple square waves
or ramps. This complicates trying to predict what extra input
capacitance or output inductance will do.
Think about it, without caps the battery just sees the controller
as a big on/off switch. On - current flows, off - no current.
No; because an SCR controller may be recharging its commutation circuits
during what would normally be the "off" time. The input current diverts
to a capacitor or inductor to store energy.
Adding inductance will slow down the time it takes the motor to
speed up and slow down, but won't effect input ripple current.
Motor inductance is usually unknown, so controllers are designed to
tolerate "lots" of output inductance. You can't have too much, as a
practical matter. So you can always add more.
The effect of more inductance depends on the controller topology. A
simple SCR Jones chopper regulates motor ripple current, so more
inductance won't help -- it just slows down the switching frequency. But
it will help with other circuits that switch at a "fixed" frequency
(i.e. one that is being controlled by something other than motor
inductance).
Besides the fact that adding inducatance will change the "ringing"
characteristics of the SCR circuit and you'd have to change other
components in order to get the SCR to switch off.
Most SCR controllers (including the GE EV-1) were built so they did
*not* depend on motor inductance. They will happily drive a purely
resistive load, or even a capacitive load.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
gary wrote:
Since this is probably the largest single collection of EV experts that
there is, and it has been a great list with lots of friendly advice and
good ideas, I'd like to see if I can get some feedback on an EV plan.
Welcome, Gary! You've gotten a lot of good advice, but I'll throw in my
2 cents.
Arthur Clarke said you should always listen to experts. When they say a
thing CAN be done, they are usually right. But when they say a thing
CAN'T be done, they are usually wrong. There may be ways; but they
haven't found them!
The experts are right in areas where they have succeeded. They have
found something that works, and they know how and why it works. That is
very useful information.
But the "experts" that have failed don't really have much useful
information to offer (except "I tried that, and it didn't work"). They
may not know why it failed, or have any useful information on how to
avoid this failure. What you want to learn from failures is how not to
repeat them!
I started on a business plan for investors...
Seems like the business plan comes *after* you've decided what it is you
want to do.
Part of that plan is to convert new cars as a short-term product
As others have pointed out, there are lots of failures and no successes
in this direction!
to test systems
This is worthwhile, just as a learning experience / R&D project. I just
wouldn't expect to may any money on this phase.
Another goal is to design subsystems for EVs.
This could be fruitful. All the successful companies in the EV
"business" make components (motors, controllers, batteries, chargers,
etc.) In part, this is because they can sell these components to the
world at large (99% of their customers are for non-EV use).
2007 Honda Fit...
If this is what you personally like, then go for it! Convert it as a
means of educating yourself.
But do not mistake your own interests for customer interest. The
customer is not like you! If you are doing something to sell, then you
have to look at the vehicles that other EVers have chosen to convert.
The goal is for a daily commuter that will briskly accelerate to
65mph for highway use, so range will be secondary. Both mine and
my wife's daily drives are well under 30 miles round trip...
You can do this on a budget with a small light car, 10-12 12v flooded
batteries, a Curtis controller, and a 6.7" ADC motor. The challenges are
mainly in getting the details right, so the driver doesn't "murder" it
from ignorance and abuse.
Changing to AC will add a lot of cost, but it will be more efficient and
have more features and "polish".
Changing to higher-tech batteries will add lots of cost, but will reduce
maintenance and it will accellerate faster.
Power accessories (power brakes, power steering, automatic transmission,
air conditioning) will also eat up lots of money. Picking a car and/or
customers that require all this "stuff" will make your job more difficult.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Steve Powers wrote:
Well, the Festiva finally got here last night about 10:30...
What do you think about 8 x 12 V exide orbitals for my 4
mile round trip commute?
jerryd wrote:
Much better would be some 60-72lb Trojan or USBattery 12vdc flooded
batteries to the max your charger and controller can do. They will
have over 2.5x's the range of Orbitals/batt while costing less and
much less likely to get murdered ;^D.
I agree with Jerry. 8 Orbitals is a very light pack. It would be easy to
murder them from abuse, especially with a simple charger and no battery
balancing. I wouldn't expect them to last more than a couple hundred
cycles. If you drive every day, they won't last a year.
If you just replace all 13 T-875's, and take care not to draw too much
current or run them too dead, they will probably cost less and last
twice as long as the Orbitals.
My only concern is the BC-20 charger. Will it kill those
batts?
It would be bad for sealed batteries. You'd need to add some method to
regulate each AGM's voltage, and control the charger so none of them go
over-voltage.
Also, I heard real bad things about Exide 6 V flooded batts.
I've used them; they are not as good as USBattery or Trojan, but they
are also cheaper. A 6v pack would certainly be the cheapest route (13 x
6v = 78v), but with that low a voltage on your existing motor and
controller, performance would be weak.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Darin - MetroMPG.com wrote:
I would spin that idea differently: a potential market for commercial
conversions might be found in people who have *already* bought NEVs,
and now have no "trade up path" (Xebra and Tesla notwithstanding).
Hmm... that gives me an idea. There are lots of old CitiCars /
ComutaCars / ComutaVans lurking about. Though they were what we'd call
NEVs today, they were *titled* as normal cars.
How about a business that rebuilds these old classics? No, you don't
"restore" them to stock, as they were terrible cars to begin with. You
"hot rod" them like the hot rodders of old did with their Ford model T's
-- you use modern parts and techniques so it is still titled as a
"Citicar" but in fact almost nothing of the original remains. :-)
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Hello Roger,
Roger writes:
> And along those lines, is there a way to predict
> capacity at higher currents than are stated on the spec
> sheets? (Typically 75 amps) I do not completely understand
> the Peukert's number calculations yet,
You might want to use "Uve's Battery Page"
(http://www.geocities.com/CapeCanaveral/lab/8679/battery.html).
About half way in are two calculators; the first takes two time/rate pairs (or
the 20hr capacity and the reserve capacity), from which it will calculate the
Peukert's exponent and "capacity", which is then used by the second calculator
to estimate capacity at other (ie. higher/EV) rates.
> but intuitively I think that it can not predict performance
> above a measured current value.
Like all extrapolations, it is an approximation, but good enough for
back-of-the-envelope EV calcs.
Cheers,
Claudio
--- End Message ---
--- Begin Message ---
Just call them, no email yet. Tell them Bob (Deckofficer) with the 0~40 mph
scooter in 2 seconds says Hi.
http://www.logisystemscontrollers.com/index.html
Bob
Eduardo Kaftanski <[EMAIL PROTECTED]> wrote:
On Wed, Jan 03, 2007 at 04:01:52PM -0800, Robert Lemke wrote:
> I use them, best bang for the buck. Bought my first controller from them 2
> years before they even had a web page. Let everyone know about them back then
> by posting on the visforvoltage forum. Never a complaint from that group.
>
Do you have an email contact for them?
--
Eduardo K. | Some say it's forgive and forget.
http://www.carfun.cl | I say forget about forgiving just accept.
http://e.nn.cl | And get the hell out of town.
| Minnie Driver, Grosse Point Blank
--- End Message ---
--- Begin Message ---
Well, let's see. This is delightfully formulatic.
100F 16v is 12800 joules. 512000 J for 40 caps.
512000J=142.222 W-hr=0.19064 hp-hr
Let's relate that to mileage of say a scooter normally uses a two stroke
with a crappy 0.65 lb/hp-hr efficiency.
That's equal to 0.1239 lb of fuel, at 6.3 lb/gal that's equal to 0.0197
gal of scooter gasoline.
So... not far! Well, if your scooter gets 45 mpg then that's 0.885 mi,
or 4676 ft, and that's assuming you can drain the cap all the way down
to 0v.
There's just something so much fun about doing practical math. Hope I
didn't make any 1:30AM mistakes.
Danny
Bruce wrote:
Even the 100F 16V car audio capacitors for $250 seem overpriced.
But still it would be interesting to experiment with a short range scooter
if you had 40 or so of them.
Probably not $10,000 worth of interesting though.
There must be cheaper sources for larger capacitors.
Where might one look for cheap, big capacitors?
What's the best deal per Farad?
Lee Hart wrote about the $250 3F 24V car audio capacitor:
That's not a super cap; it's a plain old cheap electrolytic capacitor in
a fancy overpriced package.
--- End Message ---
--- Begin Message ---
My US Electricar (1994 Chevy S10 longbed) truck has a
battery box with almost 6" wide "tunnel" over the drive shaft.
The top of the tunnel increases in height towards the rear axle
to allow the rear axle (and thus the drive shaft) to move up.
If you want exact measurements or pictures, then I need to
crawl under the truck - let me know.
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Pestka, Dennis J
Sent: Wednesday, January 03, 2007 11:28 AM
To: EV Discussion Group
Subject: Driveshaft clearance
Had some time off over the Holidays and started to work on my 1965
Datsun Pickup conversion; "WATTSUN"
Removed the pickup bed and started a CAD design drawing for my battery
boxes.
As you might imagine, the space available on this minitruck is really
limited.
My objective is to get 12 batteries under the bed of the truck.
4 on each side of the driveshaft between the cab and rear end. 4 more
behind the rear end cross member.
The space between the driveshaft and inside of frame is approximately
14".
Does anyone have a suggestion, or rule of thumb on how close you can get
to the driveshaft, and still have a safe installation?
Thanks;
Dennis
Elsberry, MO
--- End Message ---
--- Begin Message ---
(Combining 2 questions - see responses inline)
David Roden wrote:
>If the current is kept under 300 amps, East Penn (Deka) gel batteries are
>proven, consistent performers.
>
>You do know that 29 8G30Hs will weigh over 2100 lb, right?
Hi Roger,
I have a 94 S10 Longbed (standard cab) that was selected by
US Electricar for their factory EV conversion. It has a battery
box that sits on each side of the drive shaft, between the frame
rails and entirely forward of the rear axle, although I have added
a small box for a single row of 4 additional batteries behind the
rear axle (between the struts and the beam carrying the spare wheel)
See http://evalbum.com/694 for a couple of pictures,
more pictures on my website:
http://www.geocities.com/cor_van_de_water/USE/
As you can see, the original battery box has two layers of
batteries. This does not allow flooded batteries, unless you
have a very reliable automatic watering system.
There is not enough real estate (square feet) to have 39 flooded
batteries under the bed, or they need to be very small.
You could install them in the bed, but the centre of gravity will
be very high and you lose the advantage of a truck (hauling).
For sealed batteries you have the choice between AGM and Gel.
Gel have more cycle life, but can be picky about (over-)charging
which makes regen braking a very delicate issue, while AGMs are
more robust and can deliver much higher currents and absorb high
regen currents, but have a somewhat shorter cycle life and
absolutely need some sort of balancing like simple zener-regs if
you want to see them perform up to the specified cycle life.
AGMs often are cheaper than Gel batteries, although the longer
life of Gels can make the price per mile equal or better than AGM.
The AGMs I am using (26 x 12V 110Ah) weigh about 1800# and cost
approx $100 per battery if you can find them at dealer price.
This manufacturer (UPG) also has a group 30 Gel battery of
12V 100Ah, 67# which costs around $140.
The engineer quoted me a cycle life of about 400 for the AGM, which
means that I hope to get about 24,000 miles out of them.
(60 miles range at 80% DOD x 400 cycles)
I do not know the cycle life of the Gel battery, but some info
I read says that Gels may have around 600 cycles.
(Send me a mail off-list for more info about UPG pricing.)
At this moment I have 5200 miles and recently needed to replace
some batteries because I did not balance them and they slowly
drifted apart, so when I made a 63 mile Freeway run on one charge,
I must have hurt several of them.
Since this happened within a year since purchase, I got replacement
batteries under warranty.
I am now building a battery monitor to keep a close eye on them,
though all that is really necessary is a handful of zener-regs.
Zener-regs have been discussed before, essentially they are a
low voltage panel lamp in parallel with a resistor (in case the
lamp dies) and a zener diode attached to each wire of the lamp.
The zeners need to be a high wattage type and 6.2V and 6.8V for
a total voltage of 13V drop over the zeners and up to 3V lamp.
Roger Johnsonbaugh asked:
>I wanted to thank you all for your input. It is always helpful to hear
>another perspective.
>
>I especially want to thank you, Paul for reminding me that there are two
>sides to every problem. When choosing pack voltage, my thought was to keep
>it as high as possible to reduce current thus increasing capacity/charge as
>well as cycle life. I was concerned about voltage sag under load and had
>completely ignored charge voltage. Which brings us to the next point: Is
>there a quick way to predict what the voltage sag will be at a given
>current? Also, is it a similar relationship under charge? (Charge current
>being limited by internal resistance in the same proportion that discharge
>current is limited) And along those lines, is there a way to predict
>capacity at higher currents than are stated on the spec sheets? (Typically
>75 amps) I do not completely understand the Peukert's number calculations
>yet, but intuitively I think that it can not predict performance above a
>measured current value.
Voltage sag depends on resistance and current, so lower current means
less sag, also lower resistance means less sag.
More batteries means more resistance, but this is linear with the nr
of batteries and the current is inverse related to the nr of batteries
so for the same power this cancels each other out for the voltage sag,
however the lower current at high voltage means lower power loss due to
the sag (the same sag is a smaller percentage).
Resistance consists of wiring resistance, breaker, contactor and other
switch resistance and the batteries internal resistances.
The battery resistance depends on how it is made, its state of charge
and the temperature. Colder means higher resistance.
Usually the battery's resistance is specified at a certain temp and
with it fully charged, my batteries are specified for 4 milliOhm and
most cabling is below 1 milliOhm, but still I am seeing around
250 milliOhm total if I can believe the controller's DC input report
of 50V sag (320V => 270V at 200A) so I attribute the extra 100 mOhm
to losses that I have not been able to measure yet in contactors and
factory wiring, plus a higher than specified internal resistance due
to lower temp and not completely full batteries.
For charging you do not want to rely on internal resistance for
current limiting - the charger should be able to push the max
current through the batteries and control the current.
Voltage can climb as high as 15V per battery, although I usually
charge at 13.7 per battery and only occasionally bring them up
to 14.8V for equalisation.
Note that for 29 batteries, you need your charger be able to go to
29 x 15V = 435V.
This is possible, but very near the top that normal available
components go (a 240V AC supply has either a 400V or 450V capacitor)
Because charge currents are usually much smaller than discharge
(drive) currents, the voltage increase due to them is not important,
they are usually only a few volts.
For most EVs the available capacity can be estimated by taking the
1-hour capacity of available (80Ah for my 110Ah at 20hour batteries)
and apply a 80% or less safety margin, dependent on temp and
drive style, so the rule of thum is to use no more than 50% of the
capacity of the battery's spec at 20 hours to be safe as a max
normal driving range, while trying to stay within 50% of the
1 hour spec for long life.
In my case: about 60 Ah max range, trying to stay within 40 Ah
for long life. My daily 23 miles round-trip commute uses less
than 25 Ah, so I am good.
Hope this helps,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
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Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Steve Condie
Sent: Wednesday, January 03, 2007 3:24 PM
To: [email protected]
Subject: Re: Newbie questions (batteries) Cor - can you help this guy?
Roger - Cor Van der Water has a truck like yours running an AC drivetrain
with 25 UB121100 AGM batteries which he's put at least a few thousand miles
on over the past year. The UB's are an inexpensive imported, nominally 110
amp hour battery which seem to work OK in EV's. (I have a dozen myself,
but only put 600 miles on them before I took them out for my next project.
Cor would be the guy for you to get good data from.)
Roger Johnsonbaugh wrote:
I have been reading about batteries for about 8 months now and I
know about as much as I did when I started.
I am in the planning stages of a 94 S-10 conversion. I will be using a
siemens A/C drive from MetricMind....
--- End Message ---
--- Begin Message ---
Hi Darin, Gary and All,
I forgot the most likely high profit EV that no
one is buildng, regretfully an all too common problem.
It's a aero cabin 2 wh MC EV!!!
The start up costs could be very low, under
$10k for the first one if you do a lot yourself. As the
frontal area, CD, weight would be very low, you wouldn't
need an expensive EV drive and could afford to use higher
tech batts as the pack would be small.
And as the aero, rolling drag could be so, so
low, makes it a great high speed cruiser with good range on
a small battery pack and motor/controller!!
An ICE version using a BMW MC starting parts,
then making a cabin/frame for it sells for $80k and many
have been sold!!! It's called the Ecomobile I think.
I posted about the Tesla on PBS wired science
before I saw it. Great but very short pics and only a short
discussion on it. They need less happy talk and more
science, cool thing and how they work!!
Lee, I'll take your advice you gave earlier on
Cg's.
----- Original Message Follows -----
From: "Darin - MetroMPG.com" <[EMAIL PROTECTED]>
To: [email protected]
Subject: Re: new EV business
Date: Wed, 03 Jan 2007 23:00:39 -0500
>Roderick Wilde wrote:
>
>> One possibility if you want to be in the EV industry is
>> to sell NEVs. The ZENN car is just starting to take off
>> here in the Seattle area because it looks like a real
>car and that is because it is.
>
>I would spin that idea differently: a potential market for
>commercial conversions might be found in people who have
>*already* bought NEVs ... and now have no "trade up path"
>(Xebra and Tesla notwithstanding).
Yes the NEV market along with transport golf carts
have turned many to EV's and they will not give them up!!
Here in Fla at least 100k of them are used as trasport
regularly in the hundreds of senior developments and I hear
Key West, where all roads are under 35mph and only 4 miles
long, have taken over!!
And they are ripe to buy a longer range, faster
EV's they can drive beyound their community. It's a major
market I'll have to sell factories for others to help meet.
Then add new adopters, College kids, teens, techies,
commuters and while not that large a market in %, it adds to
at least 100,000yr possible US EV sales if you have a good
product that fits it. And as mine goes for just $13k, not
much more than an NEV, it should sell very well.
To be honest, the market for $30k Honda Fit
conversions will be quite small as the only one to do even
fair, the Solectria Force, only did what it did by selling
to the gov, utilities, not reg customers for the most part.
Jerry Dycus
>
>NEV owners have already demonstrated acceptance of electric
>drive. But it's electric drive with limitations: they are
>restricted to 25 mph top speed, and can only drive on
>roads with low speed limits.
>
>Surely by now there are NEV drivers who would jump at the
>chance to get "off the leash" and into an EV that can go a
>little (or a lot) faster, and has no restrictions on which
>roads it can use. These people are already spending $10k
>US and more for 25 mph. How much would they pay for a 50
>mph "unrestricted" conversion with modern safety features
>if it were marketed well?
>
>And if I'm not mistaken, it's a not an insignificant market
>- GEM has sold something like 30,000 vehicles in the US
>(though I don't know how many of those are in
>commercial/institutional settings vs. privately owned and
>used on public roads).
>
>The low-buck, relatively low speed Geo conversion I'm
>working on will essentially be an "unrestricted" NEV.
>(NEV's aren't yet legal in Ontario, where I live.)
>
>Darin
>
--- End Message ---
--- Begin Message ---
Hi Folk's
Save your money for a real Curtis or equiv controller. Last year I fooled
around with an EV-1 and an EV-100 controller 50-300 hertz switching frequency.
The pulse current is reflected back to the batteries resulting in increased I2r
losses, larger cabling required, and reduced range. I compensated with a 40kuf
cap bank in a foot square box and added a 32lb 8mh choke in series with the
motor to smooth out the discontinuous current pulses. Also these controllers
have a start-up sequence required that's a nuscance to get going. I finally
pulled all the crap out and just built another DC chopper control which is what
I usually end up doing. On my Porsche I'm working on now, I have a Curtis but
may make another fet control.
BTW, I always put a Contactor on the high throttle peddle ( conversions I've
done since the 70's) with a pre-charge resistor across the contacts for the
bulk caps in the controller. If the controller fails fully on (which has
happenned to me several times over the years) my first reacvtion is to pop my
foot off the accelerator peddle which kills the controller. I also have a
bypass contactor with a second microswitch on the potbox incase the controller
dies so I can get to the next exit without the Mac truck behind me running over
me.
Safe Motoring,
Mark
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Hi Pekka and All,
----- Original Message Follows -----
From: pekka <[EMAIL PROTECTED]>
To: [email protected]
Subject: Re: Electric for diesel swap in sailboat.
Date: Tue, 02 Jan 2007 02:52:19 +0200
>jerryd wrote:
>> Hi Myles and All,
>>
>> ----- Original Message Follows -----
>> From: "Myles Twete" <[EMAIL PROTECTED]>
>> To: <[email protected]>
>> Subject: RE: Electric for diesel swap in sailboat.
>> Date: Mon, 1 Jan 2007 10:29:15 -0800
>>
>>> Wind, solar and hydro aren't the only ways to recharge
>>> underway. And on a sailboat, may not come close to the
>>> alternatives.
>>
>> Hydro is the way on a sailboat by using the prop
>> as a rotor to turn the shunt/PM motor to use it as a gen.
>> Are you all not doing this yet? I mentioned it 10 yrs ago
>> and several times since.
>> Especially using PM or AC motors, you can just
>> use a regn controller like the Sevcon to buck up the gen
>> output to the battery voltage. It works especially well
>> with flat pitched sailboat props.
>> So while sailing or anchored in a current, you
>> can charge all you want ;^D While this isn't eff, there
>> is so much power available, most boats will need to keep
>> it turned off most of the time. And recharge while
>sailing too.
>
>Jerry,
>
>I must wonder whether you have hands on experience with
>this?
On the charging part, I built about 10 of them 20 yrs
ago for liveaboards in Key West Harbor.
I know distance sailors might risk an overcharge
>with regen if the wind is brisk for many days in a row,
>but then a 4 quadrant controller with a PM motor is
>relatively easy to adjust for less regen if desired.
You should get about 1/2 the power from a prop,
especially flat pitched ones or even better as another
posted, using a variable pitch prop, the by far best choice.
But remember these props have the opposite foil shape than
needed but still work at reduced eff. The rpm will need to
be higher depending on gen eff. Luckily there is a lot of
power available as water is 860 x's or so thicker than air.
>
>My 25' boat (15" dia 10.5" pitch prop) starts to regen at
>about 3.5 knots, makes a few amps to the batteries at 5
>knots and may reach 4-5 amps momentarily, going 6 knots or
>more - I have heard a rumour that in slightly larger boats
>, with displacement hull speed 7 to 8 knots or more, regen
>works better though.
I used double step up belts to get more rpm. Though
a 48vdc PM motor should easily put out 1/4 of it's power in
regen that a prop uses under power. You may need to use a
seperate gen with more gearing.
>
>In my boat, a 30 Wp solar panel usually produces more
>electricity than regen. Not that my boat is anywhere near
>well set for regeneration but it is a reference to me.
>
>As for the hydro-gens or tow-gens, some reach a whopping
>250 Watts at full output, at more than 5 knots in any
>case...
They mostly use 6hp Evinrude props on SS 1/2" shafts
3' long connected to a line which turns the gen but are
limited by their ability to stay underwater as too much drag
forces them to the surface. Jack Rabbit Marine makes a
river//transom unit and Motorola made an outboard like unit
but it didn't sell well enough for them.
>
>Naturally, using a really big prop, preferably with a
>shaped nozzle, would put more than float amps to the
>batteries I guess. Jerry, do you have real life examples
>of having to turn off prop regen while anchored?
Yes, they put out so much they had to be turned of
most of the time to keep from boiling the batts. Next time
you are sailing, try to stop your prop!! But b very careful
as you wil find great torques. On sailboats they broke all
but the strongest disc brakes, 5/8" pins to stop a shaft
from turning underway or in a tidal current. As sailboat's
drag increase with a spinning prop, many sailors had me
install these and how I found so much untapped power.
At the time I was a boat builder, electrician, rigger
and built windgens for boats and also lived aboard at anchor
for 20 yrs.
Jerry Dycus
>
>As for Myles' solution with a Honda genset, this an easy
>way to overcome the range limit in small sailing boats and
>other small displacement boats. For 9 tons, maybe
>something bigger than a Honda.
>
>I am using my motor to leave the marina and sometimes 15-20
>minutes to get better wind direction, so I am doing fine
>with a 220 Ah (C20) 24V pack. My brother would need a
>genset for his boat, he motors quite a lot. Your nautical
>mileage may vary ;-)
>
>Pekka
>
--- End Message ---
--- Begin Message ---
I heard that Subaru is working on a hybrid system in its early stages. Paul
Scott of Plug-In America has asked people to sign a petition to show Subaru
that a plug-in hybrid would be some thing that people would be willing to buy.
Can I ask you people to help? I want the list on the petition to go over 1000
names before the weekend. This kind of petition helps prove that there is
strong demand for EVs and EV like vehicles. Please help me by going to
http://www.petitiononline.com/subarupi/petition.html and signing the petition.
Also, so I can figure out which of the list serves and blog spots participates
the most, put in the comment section EVList. Thank you for all your help.
Currently the people on the Daily Kos are the strongest participants. Let's
show them that this list is stronger when it comes to EVs and plug-ins. Thank
you for all you can do. Sincerely, Joseph Lado
--- End Message ---
