EV Digest 6267
Topics covered in this issue include:
1) Re: Newbie Questions (Batteries)
by "Peter VanDerWal" <[EMAIL PROTECTED]>
2) Re: 36volt Cursis usable with 40volts?
by Lee Hart <[EMAIL PROTECTED]>
3) Fwd: FW: 36volt Cursis usable with =?UTF-8?B?NDB2b2x0cz8=?=
by Tim Humphrey <[EMAIL PROTECTED]>
4) Re: Exide orbitals
by "Peter VanDerWal" <[EMAIL PROTECTED]>
5) Battery theory
by JS <[EMAIL PROTECTED]>
6) new EV business
by "gary" <[EMAIL PROTECTED]>
7) Re: Exide orbitals
by Tony Hwang <[EMAIL PROTECTED]>
8) RE: new EV business
by "damon henry" <[EMAIL PROTECTED]>
9) Re: Exide orbitals
by "damon henry" <[EMAIL PROTECTED]>
10) RE: Joe Sixpack Geo: best controller SCR, Curtis or contactors? (Or some
combination)
by "Roger Stockton" <[EMAIL PROTECTED]>
11) Re: 36volt Cursis usable with 40volts?
by "Chris" <[EMAIL PROTECTED]>
12) RE: AltairNano Completes ORDER to Phoenix Motorcar
by [EMAIL PROTECTED]
13) RE: Joe Sixpack Geo: best controller SCR, Curtis or contactors? (Or some
combination)
by "Roger Stockton" <[EMAIL PROTECTED]>
14) Re: Joe Sixpack Geo: best controller SCR, Curtis or contactors? (Or
some combination)
by Lee Hart <[EMAIL PROTECTED]>
15) Re: Joe Sixpack Geo: best controller SCR, Curtis or contactors?
(Or some combination)
by "Darin - MetroMPG.com" <[EMAIL PROTECTED]>
16) Re: DC to DC converter - why isn't it just a big transformer?
by Lee Hart <[EMAIL PROTECTED]>
17) RE: Exide orbitals
by "Roger Stockton" <[EMAIL PROTECTED]>
18) Re: Potential EV Chasis on e-bay
by "David Roden" <[EMAIL PROTECTED]>
--- Begin Message ---
> Which brings us to the next point: Is
> there a quick way to predict what the voltage sag will be at a given
> current?
Sure, use Ohm's law. Find the batteries internal resistance (some
manufacturers post this info) and multipy it by the current. This will
equal the voltage drop for the individual battery, multiply this by the
number of batteries.
Of course this is only fairly accurate with a fully charged battery. As
the charge drops, the internal resistance goes up, and unloaded voltage
goes down.
> Also, is it a similar relationship under charge? (
Yup, just in the other direction. I.e. the charge voltage has to go UP.
> Charge current
> being limited by internal resistance in the same proportion that discharge
> current is limited)
Pretty much, that is until the battery gets to be about 80% full. Then it
starts gassing, this means that the voltage is high enough that
electrolysis occures and the water starts to separate into hydrogen and
oxygen. If you continue to charge at a high current, most of it will end
up going into gassing and you'll waste water (or vent the battery if it's
sealed).
So when you hit this point you need to limit voltage, this has the effect
of limiting current.
> 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.
Peukert's effect is an approximate method and Peukert's number for a given
battery is derived by measuring capacity at a couple different current
levels. The further from these measurements your actual applied current
is, the less accurate Peukert is. This is especially true at very high
currents (hundreds or thousands of amps).
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
Chris wrote:
I'm stuck with a 24/36V Curtis 1205 but have a motor that can deal
with more. As a workaround... I'm thinking of paralleling the
bypass contactor with another pair of contactors which switch
in another one or two batteries in series with the main batteries...
The Curtis 1205 doesn't have a bypass contactor. It has an on/off
contactor if you handle reverse mechanically; or two contactors (forward
and reverse) if you handle reverse electrically.
You can switch additional batteries in series, but it can be tricky. If
the extra voltage ever gets across any two wires, by any "sneak" paths,
you can destroy the controller!
Additional batteries that are only used "sometimes" is generally a poor
practice. They tend to get out of balance, causes charging problems and
shorter battery life.
A better method is to split your pack into two equal half-packs. Include
switching to arrange them in series or parallel. This makes charging
easy; you can do it at 24v or 48v, whichever is more convenient. You're
always using all batteries, so they tend to stay in balance.
In your case, you could have two 24v packs that can be switched in
parallel for 24v, or in series for 48v. The 1205 controller can't
withstand 48v, but you can arrange the circuit so the 24v step gives you
smooth control from 0-24v; and the 48v step gives you smooth control
from 24v-48v. I published the circuit for doing this on the EV list a
while back.
--
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 ---
Ed;
I got a kick out of your sig line....
I remember the first time I saw my kids watching that video, I thought "cool, a
music video about EV-ers, I'll have to send that link to the EVDL".
I know some will be offended...oh well, lighten up.
http://www.youtube.com/watch?v=-xEzGIuY7kw
Stay Charged!
Hump
also, white and nerdy
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Eduardo Kaftanski
Sent: Tuesday, January 02, 2007 2:55 PM
To: [email protected]
Subject: 36volt Cursis usable with 40volts?
Whats the tolerance for a 36v Curtis Controller?
(6 volts batts are out of stock in the entire country. but 8 volts are in
stock... can I run a 36 volts system on 5x8 volts)
Thanks.
--
Eduardo K. |
http://www.carfun.cl | I'm white and nerdy
http://e.nn.cl | Weird Al
|
--- End Message ---
--- Begin Message ---
> What do you think about 8 x 12 V exide orbitals for my 4 mile round trip
> commute? The car is about 2500 lb with the 13 T-875's. It has a 9" ADC
> motor and 400 A Curtis controller. There is no DC-DC (all accys run off
> a seperate battery). I like the idea of sealed batts.
Well, if you are only driving 4 miles a day, a big spring and a key will
almost do the trick ;-)
Seriously though, you are going to switch from a bit over 800lbs of lead
to a bit over 300 lbs. Your range will be about 1/3 of what it was with
new T-875s, do you know what that was?
The orbitals will only be about 15% of the total vehicle weight, that's a
pretty light pack.
At a swag, I'd guess that it should do the 4 miles...for about 6-12 months
before the batteries died.
Add some battery regs and a better charger and you can probably get 2
years out of them.
A new set of T-875s, on the other hand, will probably die of old age
before you can run them into the ground at 4 miles a day. Assuming of
course that you don't murder them first. Old age, in this case, will be
5-10 years, depending on how often you overcharge them.
>
> My only concern is the BC-20 charger. Will it kill those batts?
Depends on whether you shuck out the bucks for battery regs or not.
> Also,
> I heard real bad things about Exide 6 V flooded batts.
I've only heard good things about the Orbitals on this list, as long as
you take care of them properly.
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
What is the electrical capacitance of a PbA battery (in Farads)?
Is this 'surface charge'?
John in Sylmar, CA PV EV
--- End Message ---
--- Begin Message ---
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 ---
Is it possible to keep AGM's balanced by using a small charger for each
individual battery? That way at least they all get fully charged, though you
are still limited to the capacity of your weakest cell.
- Tony
jerryd <[EMAIL PROTECTED]> wrote:
Hi Steve and All,
----- Original Message Follows -----
From: Steve Powers
To: [email protected]
Subject: Exide orbitals
Date: Wed, 3 Jan 2007 03:50:57 -0800 (PST)
>Well, the Festiva finally got here last night about 10:30,
>and I have to say the T-875s in there are compleyely shot.
>It has 9500 miles on those batts, and 2 were so bad they
>were already taken out, so it is only running 88 V now.
Congrats on your new EV!!
>
> What do you think about 8 x 12 V exide orbitals for my 4
>mile round trip commute? The car is about 2500 lb with the
>13 T-875's. It has a 9" ADC motor and 400 A Curtis
>controller. There is no DC-DC (all accys run off a
>seperate battery). I like the idea of sealed batts.
I don't think it's a good choice. Much better would
be some 60-72lb Trojan, USBattery 12vdc flooded batts to the
max your charger, 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. Now add to that the
BMS regs you need to keep AGM's alive and the costs are just
too high for what you get. Maybe if you had a Zilla
controller it might be different.
Flooded batts are easy to take care of if you coat
the terminals and spray them down with a hose every month or
so.
>
> My only concern is the BC-20 charger. Will it kill those
>batts? Also, I heard real bad things about Exide 6 V
>flooded batts.
Orbitals are the only good Exide batt product and
they were/ are designed made in Spain when they bought it's
maker. Exides 6-8-12vdc batts ar not very good in EV's,
dieing early.
Jerry Dycus
FYI, I planned to buy them at the Sam's
>Club. I think they are around $100 / ea.
>
> Thanks,
>
> Steve
>
> __________________________________________________
>Do You Yahoo!?
>Tired of spam? Yahoo! Mail has the best spam protection
>around http://mail.yahoo.com
>
--- End Message ---
--- Begin Message ---
It sounds like you will end up with a $30K Honda Fit to drive around in.
Seriously, if people were interested in paying $30K for a brand new Honda
Fit, Honda would be selling them for that much. There is probably a very
small market out there for a product like this, but good luck at finding
them. From what I can see most EV's need to be sold for less than what they
cost to make before anyone is interested in buying them.
Jerry is planning on turning a profit on his Freedom EV and has stated many
times that he plans on just getting things running and then handing the
reigns over to someone else, so perhaps that is a good opportunity for you.
His design has the advantage of being developed from the ground up as a low
cost solution. You are at the disadvantage of having to buy a product at
full retail, then pull much of the value out just to get started.
If you want to do it, and can do it, it sounds like fun, but I do not see it
as a viable way to make money now or in the future. It certainly sounds
like a great thing to be doing if you want to drive the end product
yourself, and gain valuable experience along the way.
Damon
From: "gary" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: <[email protected]>
Subject: new EV business
Date: Wed, 3 Jan 2007 11:13:29 -0600
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
_________________________________________________________________
Your Hotmail address already works to sign into Windows Live Messenger! Get
it now
http://clk.atdmt.com/MSN/go/msnnkwme0020000001msn/direct/01/?href=http://get.live.com/messenger/overview
--- End Message ---
--- Begin Message ---
Yes, this is a solid strategy. The one big gottcha is that you need to have
a way of knowing that all the individual charges are functioning correctly.
Some day, it may be tomorrow, it may be years down the road, at least one of
your individual chargers will fail. You need to know that this has happened
and have a way to deal with it, or you will quickly destroy the undercharged
battery.
Damon
From: Tony Hwang <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: Re: Exide orbitals
Date: Wed, 3 Jan 2007 10:09:24 -0800 (PST)
Is it possible to keep AGM's balanced by using a small charger for each
individual battery? That way at least they all get fully charged, though
you are still limited to the capacity of your weakest cell.
- Tony
jerryd <[EMAIL PROTECTED]> wrote:
Hi Steve and All,
----- Original Message Follows -----
From: Steve Powers
To: [email protected]
Subject: Exide orbitals
Date: Wed, 3 Jan 2007 03:50:57 -0800 (PST)
>Well, the Festiva finally got here last night about 10:30,
>and I have to say the T-875s in there are compleyely shot.
>It has 9500 miles on those batts, and 2 were so bad they
>were already taken out, so it is only running 88 V now.
Congrats on your new EV!!
>
> What do you think about 8 x 12 V exide orbitals for my 4
>mile round trip commute? The car is about 2500 lb with the
>13 T-875's. It has a 9" ADC motor and 400 A Curtis
>controller. There is no DC-DC (all accys run off a
>seperate battery). I like the idea of sealed batts.
I don't think it's a good choice. Much better would
be some 60-72lb Trojan, USBattery 12vdc flooded batts to the
max your charger, 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. Now add to that the
BMS regs you need to keep AGM's alive and the costs are just
too high for what you get. Maybe if you had a Zilla
controller it might be different.
Flooded batts are easy to take care of if you coat
the terminals and spray them down with a hose every month or
so.
>
> My only concern is the BC-20 charger. Will it kill those
>batts? Also, I heard real bad things about Exide 6 V
>flooded batts.
Orbitals are the only good Exide batt product and
they were/ are designed made in Spain when they bought it's
maker. Exides 6-8-12vdc batts ar not very good in EV's,
dieing early.
Jerry Dycus
FYI, I planned to buy them at the Sam's
>Club. I think they are around $100 / ea.
>
> Thanks,
>
> Steve
>
> __________________________________________________
>Do You Yahoo!?
>Tired of spam? Yahoo! Mail has the best spam protection
>around http://mail.yahoo.com
>
_________________________________________________________________
Get FREE Web site and company branded e-mail from Microsoft Office Live
http://clk.atdmt.com/MRT/go/mcrssaub0050001411mrt/direct/01/
--- End Message ---
--- Begin Message ---
James Massey wrote:
> Put it in and upgrade it later.
Darin, I'm with James on this. The controller will be harder on the
batteries than a modern controller, and your range will be less, but it
will get you on the road and has built-in safeties that a homebrew
contactor controller might very well lack.
As for upgrading, I know the theme of your project is "budget", but I'd
suggest skipping the Curtis and go for an Alltrax controller if/when you
feel the need to upgrade to a more modern unit. The AXE-4865 (24-48V,
650A) would be a logical upgrade, but I'd suggest going for the AXE-7245
(unless they have a 7265?), which handles 24-72V, 450A so that you have
the ability to increase your pack voltage should you feel the need for
greater range and speed:
<http://www.alltraxinc.com/old/prod09.htm>
> From what I read, the SCR controller will roughly halve the range
> potential of the batteries, if the controller spends most of
> its' time in mid-range PWM.
It depends a lot on the batteries, as well as on the driving style (as
James notes below). I've heard the 50% range reduction from people
using T105-ish floodies; I'm using Optima YTs, which shrug off high
currents much better, and I get about 27Ah from them vs the 34-ish that
others with modern controllers quote. Bear in mind that my YTs are also
something like 7-year old blems whose capacity is lower than rated to
start with.
> However, if it spends most of its' time in bypass it will
> make almost no difference at all.
I'm guessing that hitting your 40MPH top end target with a 48V pack may
well require wide open throttle operation, and once the bypass closes
this setup is more efficient than even modern PWM controllers.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
--- In [EMAIL PROTECTED], Lee Hart <[EMAIL PROTECTED]> wrote:
>
> Chris wrote:
> > I'm stuck with a 24/36V Curtis 1205 but have a motor that can
deal
> > with more. As a workaround... I'm thinking of paralleling the
> > bypass contactor with another pair of contactors which switch
> > in another one or two batteries in series with the main
batteries...
>
> The Curtis 1205 doesn't have a bypass contactor. It has an on/off
> contactor if you handle reverse mechanically; or two contactors
(forward
> and reverse) if you handle reverse electrically.
>
> You can switch additional batteries in series, but it can be
tricky. If
> the extra voltage ever gets across any two wires, by any "sneak"
paths,
> you can destroy the controller!
>
> Additional batteries that are only used "sometimes" is generally a
poor
> practice. They tend to get out of balance, causes charging problems
and
> shorter battery life.
>
> A better method is to split your pack into two equal half-packs.
Include
> switching to arrange them in series or parallel. This makes
charging
> easy; you can do it at 24v or 48v, whichever is more convenient.
You're
> always using all batteries, so they tend to stay in balance.
>
> In your case, you could have two 24v packs that can be switched in
> parallel for 24v, or in series for 48v. The 1205 controller can't
> withstand 48v, but you can arrange the circuit so the 24v step
gives you
> smooth control from 0-24v; and the 48v step gives you smooth
control
> from 24v-48v. I published the circuit for doing this on the EV list
a
> while back.
>
If you wouldn't mind giving a pointer to it Lee I would appreciate
it. My Curtis 1205X does have the bypass fitted (perhaps why i have
an 'X' suffix ?) so I would use bypass, but would be interested in
splitting the pack to get another way to not limit voltage to the
limits of the controller. Thank You
--- End Message ---
--- Begin Message ---
Last October, I went to the 2006 Solar Conference and visited
Altairnano's booth. I spoke with Veselin Manev, their chief
research scientist, who showed me the raw data, and filled me in on the
principles which make the batteries perform. Unless the data I saw
was contrived (it was in a raw format, not "buttered up" for
presentation), I had no doubt that these would be the next wave of
batteries.
I showed Veselin and Roy Graham (their marketing director
at that time) my somewhat silly but semi-credible article about my
scooter trip from Port Townsend, WA to Seattle and back on Lead Acid,
and offered to test their batteries. I was promised a small
prototype pack to test this January.
I don't want to say too much until A) I can
physically touch the batteries and B:) I'm done running the
tests.
Wish me luck on test
pack acquisition. I'll post results as soon as I have
them.
-Sam
-------- Original Message
--------
Subject: Re: AltairNano Completes ORDER to Phoenix
Motorcar
From: Peter Eckhoff <[EMAIL PROTECTED]>
Date:
Tue, January 02, 2007 9:06 am
To: [email protected],
[EMAIL PROTECTED]
Bill Moore of EV World was talking with Dr.
Gotcher, CEO of Altair
Nanotechnologies. Gotcher mentioned to
Bill Moore that a **cell** in
the Altair labs has been recycled
20,000 times and still had a residual
capacity of 85%. The
conversation occurred at the Boston ASPO dinner
meeting.
Bill stated this in an EV World Insider
newsletter.
However, when you start to put cells together to
form a battery, cycle
life tends to go down. A 20,000 cycle
battery (as opposed to a cell)
would be a 2.6 million mile pack at
an average of 135 miles per cycle.
The battery warranty on
the Phoenix site is 250,000 miles/12+ years.
Just a factor of
10 less. Warranties tend to be conservative.
The contract
for the initial order was for $750,000 for 10 vehicles. I
could see where someone would come up with $75K for each pack.
However,
the cars have a price point of $45,000.
Nick: Is your quote of approximately $14K per for a 35
kWh pack
correct? ($14K for a pack / 250K miles = 5.6 cents /
mile.)
250Kmiles/135mile per cycle = 1851
cycles.
Peter
Brandon Kruger wrote:
> I think I
even read they're good for > 10000 full discharge cycles?
> But I
> can't remember where I read that.
Anyone else see it?
>
>
>
Brandon
>
> On 1/1/07, Nick Austin
<[EMAIL PROTECTED]> wrote:
>>
>> On Mon, Jan
01, 2007 at 11:24:43PM +0200, Kaido Kert wrote:
>> > A
commenter on the Energy Blog set the record straight on the cost
of
>> > the batteries:
>> >
http://thefraserdomain.typepad.com/energy/2006/12/altairnano_comp.html
>>
> quote:
>> > NO, the battery packs do NOT cost
$75,000
>> > apiece. They cost approximately $14,000
each.
>>
>> Is this $14,000 for a 35 kWh pack with
BMS that lasts > 10000 cycles?
>>
>> This seems
like a great deal!
>> Where do I sign?
>>
>>
Thanks!
>>
>>
>
>
--- End Message ---
--- Begin Message ---
Lawrence Rhodes wrote:
> > I have an SCR based controller in the Electravan that switches
> > at 1500 hz with inadequate filtering on the battery side.
> > Is it possible that the battery sees high current pulses and
> > behaves more like it is discharging at 1000 amps than 100 and
> > consequently has much less capacity.
You were/are almost 2 orders of magnitude optimistic on the switching
frequency of your EV-1, which will impact the amount of capacitance
required (you'll require more). The controller actually switches
between 50-300Hz.
Lee wrote:
> These old SCR controllers usually didn't have a large input
> filter capacitor bank. There were several reasons.
>
> First, they expected them to be used with huge forklift
> batteries, which already have lots of capacitance (a "mere" 1000
> amp load for these batteries isn't a high rate :-)
Which reveals another way to reduce the impact of the ripple: use larger
capacity batteries than ordinary T105-ish ones, and/or use batteries
that are less bothered by high discharge rates (yes, Peukert will still
bite into your range, but not as much and at least the batteries will
last longer). Going to larger floodies is less of an option for someone
like yourself with a 120V pack, however, Darin with his 48V system could
go for a set of larger floodies (like 400Ah L16-ish ones), or even
(though this is counter to his budget conversion theme) a set of L16-ish
AGMs, such as the Discover EVL16A-A:
<http://www.discover-energy.com/ev_specs.php?specs=EV&battType=agm&produ
ctTable=1&table=1>
> We don't have enough data to calculate a value, but it's going
> to take thousands of microfarads. If it were me, I'd look for
> some surplus electrolytics intended for switching power supply
> filtering, and put in 1,000uf worth. Measure your ripple current
> again, and see how much it dropped. Then you can guess how much
> more it will take.
Once upon a time I calculated what I'd need to significantly reduce the
ripple with my 120V pack of YTs; the value was nearer to 100,000uF in
order to reduce the impedance of the cap bank to a low enough value at
the low switching frequency of this controller. I've got a few 10's of
thousands of uF to throw at it one of these days, but the complication
of adding precharge logic, etc. is a nuisance that keeps encouraging me
to put it off ;^>.
Another way to attack the ripple problem is to add inductance to the
motor loop. Basically, the battery sees huge ripple because the motor
doesn't have enough inductance to keep the current flowing during the
off period of the PWM cycle, so the motor loop current drops to [near]
0A before the main SCR turns back on. A source of suitable inductors
are large welders; they typically have a large inductor ("reactor") in
series with their output. I got mine (still not installed) from David
Chapman (<[EMAIL PROTECTED]>), who is on this list. While it is
unlikely that you can add enough inductance to the motor loop to reduce
the ripple to a low level, it can reduce the amount of capacitance
required on the battery side (and the inductor is cheaper than the
additional capacitors ;^).
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Darin - MetroMPG.com wrote:
I got the old EV-1 controller properly hooked up and working...
A Rube Goldberg dimmer switch! Thanks, guys.
Great! That's what this EV list is good at.
If the goal is to do what's best for battery longevity & most range
per charge (town driving), what should I do?
- The car's intended use is as a low speed (35-40 mph), short-range
(20 km) runabout in a small town.
These two statements are somewhat contraditory.
Battery longevity isn't affected by the type of controller (SCR, MOSFET,
contactor), but rather by how much *power* you actually draw from them.
A low-power controller (of any type) is gentler on the batteries, so
they last longer. Conversely, a high-power controller (of any type) will
let you quickly beat the batteries to death with more spirited driving.
You said you want long range; then said short range is fine. Here again,
controller power and how you drive has a bigger effect on range than
controller type, because all types are >90% efficient.
- As mentioned, I've already got an OEM 24-48v SCR GE EV-1 controller
(with OEM bypass circuit).
- I have half a dozen beefy contactors (and a big field-weakening
resistor) that could be used to make a contactor controller (CC).
- I could spend 100 bucks (shoe-string budget) to pick up a low end
24-48v Curtis controller around 275 A.
- Haven't bought batteries yet, but it'll likely be six or eight 6v
floodies.
Flooded golf cart batteries have a higher internal resistance and
Peukert exponent. This means that high currents cause a larger
performance loss and life reduction. Of course they are also relatively
cheap; beating them to death early has fewer economic consequences.
> Since I already have the SCR and it works, I'm tempted to just start
> with that. But I understand its lack of capacitors on the input side
> makes it relatively hard on the batteries (shortening life & range)
> compared to a Curtis or a CC.
The GE SCR controller is built for very large fork lift batteries, and
very long, slow discharges (like an 8-hour shift). The lack of input
filter capacitors didn't matter much in this application.
If you will be driving it hard with weaker golf cart batteries, you will
get a reduced *range* from the lack of capacitors; but battery *life*
won't be any different than it would be with any other controller driven
equally hard.
Of course you could add the capacitor; but they are big and expensive;
you'd have to get a "good deal" on them surplus to make it worthwhile.
You could also use lower-resistance batteries, like AGMs or nicads; they
don't care as much about the high peak currents.
Note that when the EV-1's bypass contactor is closed, the ripple current
disappears, so it is no longer an issue. But you're still running at
"full power", and will suffer from the associated lack of range.
A hundred buck Curtis may be better for the batteries, but a cheap
one will have much lower performance (acceleration & max speed,
relative to the EV-1 or CC).
Correct. A little Curtis will be easy on the batteries by *preventing*
you from accellerating or driving fast.
The CC approach is appealing for its simplicity & efficiency, but
I have read some people question its effect on range (since it draws
lots of current each time the controller switches "up" until the
motor gains speed after each switch).
Not with a series motor; it behaves like a resistor. When the contactor
controller doubles the voltage, the motor current also doubles.
Here's an example (my old ComutaVan with a 3-step contactor controller:
1. From a stop, the first step is 36v with resistor; motor current
started at 250a (125a per 6v battery). As speed increased, motor
current fell to 150 amps at 5 mph.
2. Pressing the accellerator to the next step applied 36v direct to
the motor. Current stepped up to 250a again. As speed increased,
motor current fell to 125a at 10 mph.
3. Pressing the accellerator the rest of the way applied 72v direct
to the motor. Current stepped up to 250a again. Motor current fell
to 125a at 20 mph.
4. At this point, release the accellerator (motor off), shift to the
next higher gear, then step down to the 2nd step (36v). Again,
current would roughly double back to 250a. Since the motor was
already spinning, skip the 36v+resistor step as it's not needed.
The big problem with a contactor controller is that they have no current
limit. Nothing stops you from skipping the resistor step from a dead
stop, or from "flooring it" before the current has fallen in a given
step. Doing this gets the fastest acceleration, but the shortest range
and worst battery life (as well as "beating to death" other parts)!
What about a "hybrid" approach: the Curtis for starting and very low
speed, with some contactors for cruising speed?
Yes, you can do this. It's more complicated; but done right, more
complexity makes it work better.
If I were you, I'd experiment. You already have the parts to build
either a contactor controller or SCR controller; so try them first. Put
each controller in a box that is easy to swap out. You can look for a
Curtis, and put it in a third box. Once you're measured the performance
of each of them, you'll know what works best for your particular situation.
--
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 ---
James Massey wrote:
Put it in and upgrade it later. All the contactors, fuses and stuff that
are needed for a Curtis or whatever will be needed for the EV-1, the
EV-1 just has the extra bypass contactor.
From what I read, the SCR controller will roughly halve the range
potential of the batteries, if the controller spends most of its' time
in mid-range PWM.
That's good to know, and thanks for the EV-1 specific driving lesson
too. (I'm not being facetious!)
Sounds like it may be a case of monitoring how much I can effectively
keep the controller bypass active (ie foot to the floor) in routine
driving once at "cruising" speed. If I can do it much of the time, then
the EV-1 would be fine. If not, then a Curtis might be more suitable.
Or, improve the EV-1 ...
Lawrence Rhodes wrote:
> Here is what Lee Hart had to say about modifying an SCR for better
> effeciency. It's basically a capacitor bank to eliminate ripple effect.
Thanks for reminding me of that post, Lawrence. I had read it while
mining the archive for EV-1 info. Did you end up applying this mod to
your SCR controller successfully?
I have relatively little experience with electronics, so I can't say
that I understood it completely. But I'm not averse to learning, so
it's something I would look into if it could make the EV-1 more battery
friendly, affordably. But first I'll have to look up "microfarad" :-)
Darin
--- End Message ---
--- Begin Message ---
Jake Oshins wrote:
Why isn't a DC to DC converter as simple as a big transformer?
It's a transformer, plus a set of big transistors, and the associated
circuitry to form an inverter. It's not exactly hard; but does require
special skills and parts that you can't get at Radio Shack.
I ask because I'm looking at making the existing power steering pump
work in my conversion project and I'm looking at using various surplus
motors that run on voltages significantly smaller than my pack voltage.
Then you want a motor controller, not a DC/DC converter. Motor
controllers are quite a bit simpler, and don't have transformers.
Also keep in mind that the specified voltage for a motor is only one
suggested operating point. You can run them at much higher or lower
voltages, with a corresponding change in rpm and torque.
--
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 ---
Peter VanDerWal wrote:
> At a swag, I'd guess that it should do the 4 miles...for
> about 6-12 months before the batteries died.
They'll do the 4mi round trip easily. I'm running 10YTs in my ~2000lb
car and despite consuming about 2x the Wh/mi as I should, I still manage
an 8mi commute (each way, but I charge at work).
Don't forget that the 2500lb Steve quotes is most likely the curb weight
including the 800lbs of floodies; his Festiva should be down to 2000lbs
or less going to a set of Orbitals. The lighter, stiffer pack will make
the car feel much peppier.
> A new set of T-875s, on the other hand, will probably die of old
> age before you can run them into the ground at 4 miles a day.
This is true, but the car would be a lot less enjoyable to drive with
all that extra lead onboard. If Steve takes care with charging his
Orbitals, he could probably get a couple of years from a set. If this
cost is acceptable, go for it!
> > Also,
> > I heard real bad things about Exide 6 V flooded batts.
I'm not sure if this opinion is based on experience with recent product
or if it is the result of someone's bad experience years ago. A local
EVer runs a 144V pack of Exide 8Vers in his RX7 and has been quite
satisfied with them.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
On 2 Jan 2007 at 14:16, Steve Powers wrote:
> I like the Festiva. ... I think it makes a
> great EV, but the chasis is hard to find. I don't know how long parts will
> be available, but while its working, I'm going to keep driving it
These cars were still sold in South Korea (as the Kia Pride) until the early
2000s. The base model was priced at under $5000 in 2001! Overseas
suppliers in Asia and possibly in Europe will probably continue to provide
parts for many more years, so it will just be a matter of finding a contact.
They are not the highest quality gliders around, but the chassis are
reasonably sturdy, and the boxy shape lends itself well to stuffing in
batteries.
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Want to unsubscribe, stop the EV list mail while you're on vacation,
or switch to digest mode? See how: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" or "etpost" addresses will not reach me.
To send a private message, please obtain my email address from
the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
--- End Message ---
