EV Digest 4598
Topics covered in this issue include:
1) RE: EV ceramic heater - EVTech list?
by Rod Hower <[EMAIL PROTECTED]>
2) (no subject)
by Reverend Gadget <[EMAIL PROTECTED]>
3) Toyota Camary
by Cwarman <[EMAIL PROTECTED]>
4) Re: ADC vs. Netgain / how about Prestolite?
by "Paul G." <[EMAIL PROTECTED]>
5) Re: ADC vs. Netgain / how about Prestolite?
by Cwarman <[EMAIL PROTECTED]>
6) RE: Alltrax Controller
by "Paschke, Stephen" <[EMAIL PROTECTED]>
7) Re: ADC vs. Netgain / how about Prestolite?
by Brad E Jensen <[EMAIL PROTECTED]>
8) Fw: Help me decide!
by "Mark Hanson" <[EMAIL PROTECTED]>
9) Re: Toyota Camary
by Stefano Landi <[EMAIL PROTECTED]>
10) Re: Fw: Help me decide!
by "Peter VanDerWal" <[EMAIL PROTECTED]>
11) Re: Toyota Camary
by Cwarman <[EMAIL PROTECTED]>
12) Re: Toyota Camary
by Cwarman <[EMAIL PROTECTED]>
13) Re: Toyota Camary
by Cwarman <[EMAIL PROTECTED]>
14) Re: Kilovac Czonka II Relay Question
by Victor Tikhonov <[EMAIL PROTECTED]>
15) RE: 100 mile range, Re: Alternative batteries
by "Noel P. Luneau" <[EMAIL PROTECTED]>
16) 100 mile range,
by "STEVE CLUNN" <[EMAIL PROTECTED]>
17) Re: Help me decide!
by Lee Hart <[EMAIL PROTECTED]>
18) Re: Field Weakening in shunt or series
by Lee Hart <[EMAIL PROTECTED]>
19) Taper Lock Hub help needed
by <[EMAIL PROTECTED]>
20) Re: Help me decide!
by Lee Hart <[EMAIL PROTECTED]>
21) Re: Request for some required reading.
by "John J Januszewski" <[EMAIL PROTECTED]>
22) Re: Correct AGM finish charge (Was: Re: PFC-30)
by Victor Tikhonov <[EMAIL PROTECTED]>
--- Begin Message ---
Don,
I was on that list but haven't seen any email lately.
Maybe I was unsubscribed?.
I can't bring up the link you posted below.
Is there a mirror for this info. Is it archived
anywhere?
I think should resubscribe, how do I go about doing
that?
What happened to Sheer?
Thanks,
Rod
--- Don Cameron <[EMAIL PROTECTED]> wrote:
> If you are a member of EVTech mailing list, there
> was **a lot** of
> discussion on this exact subject. Look at
> www.brassrat.net/ev
>
> Don
>
>
>
>
> Victoria, BC, Canada
>
> See the New Beetle EV Conversion Web Site at
> www.cameronsoftware.com/ev/
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
> Behalf Of Rod Hower
> Sent: August 18, 2005 7:24 PM
> To: [email protected]
> Subject: EV ceramic heater
>
> I have a 120Vac heater core that is running off a
> 156Vdc pack. This pushes
> the heater to temperatures that are higher than some
> plastic ducting can
> withstand. I was thinking about using a bimetalic
> switch in the heat path
> to turn off the heater. This was used on many older
> style clothes dryers.
> Any advice on the bimetalic switch part number would
> be appreciated (or at
> least a web site for a range of temp switches so I
> can choose one that may
> work in this application).
> Thanks,
> Rod
>
>
--- End Message ---
--- Begin Message ---
digest
visit my website at www.reverendgadget.com
--- End Message ---
--- Begin Message ---
Also found a good deal on a 99 Camary for sale with a blown motor....Is
this car to heavy for a good conversion ?
Cwarman
--- End Message ---
--- Begin Message ---
On Aug 18, 2005, at 10:52 PM, Jim Husted wrote:
I’ve recently landed some really nice used 9 inch Advances and
Prestolites and will probably throw the Prestolites Does anyone out
there use Prestolites?) into my project and modify and sell the
Advances. In fact either is just as good, and I will hope to prove
that if I can get my project off the ground. I was born and bred
Prestolite and well I’m partial to many of their models also.
I'm a bit partial to Prestolites. Both EVs I've built have been powered
by Prestolite MTC-4000 series motors. I have a nice old one with the
aluminum ring instead of the finned end bell protecting the fan. The
brush end bell was never drilled for mounting. Its pretty hanging out
of the back of my beach buggy.
Paul "neon" G.
--- End Message ---
--- Begin Message ---
If all three motors are basically as good as each other , would it be
prudent to shop for the best price between them ? Im about to purchase
my first glider and trying to find out which engine is gonna be my best
bang for the buck..
Thanks paul
Cwarman
Paul G. wrote:
On Aug 18, 2005, at 10:52 PM, Jim Husted wrote:
I’ve recently landed some really nice used 9 inch Advances and
Prestolites and will probably throw the Prestolites Does anyone out
there use Prestolites?) into my project and modify and sell the
Advances. In fact either is just as good, and I will hope to prove
that if I can get my project off the ground. I was born and bred
Prestolite and well I’m partial to many of their models also.
I'm a bit partial to Prestolites. Both EVs I've built have been
powered by Prestolite MTC-4000 series motors. I have a nice old one
with the aluminum ring instead of the finned end bell protecting the
fan. The brush end bell was never drilled for mounting. Its pretty
hanging out of the back of my beach buggy.
Paul "neon" G.
.
--- End Message ---
--- Begin Message ---
I could write such an app, but it is difficult without the protocol specs and
without a protocol analyzer. I could hack something if you capture the
datastream.
Steve Paschke
APPS Support
Sr. Consultant
Keane, Inc.
303-607-2993 office
303-204-9280 cell
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Rod Hower
Sent: Thursday, August 18, 2005 2:43 PM
To: [email protected]
Subject: Re: Alltrax Controller
I agree, it would really be nice to use a Palm Pilot
or Windows CE device if somebody is willing to write
the app. I don't have experience with this although I
would like to try. Unfortunately I don't have time
right now.
Rod
--- damon henry <[EMAIL PROTECTED]> wrote:
> Philippe,
>
> Are you trying to hack the Alltrax data stream? If
> so I would like to know
> how it comes out. Shortly after I purchased my
> controller I contacted
> Alltrax to see if they had any published specs on
> this data, and they said I
> had to use an Windows NT Class machine and their
> program. I really don't
> want to strap a laptop to my motorcycle.
>
> damon
>
>
> >From: "Philippe Borges"
> <[EMAIL PROTECTED]>
> >Reply-To: [email protected]
> >To: <[email protected]>
> >Subject: Re: Alltrax Controller
> >Date: Thu, 18 Aug 2005 01:16:40 +0200
> >
> >i have one driving a Lynch motor (3000km now) i'm
> pleased with it.
> >Data logging is a great feature for vehicle
> development.
> >I'm trying to have a connexion to a dashboard LCD +
> micro from alltrax
> >RS232, still spying the data though.
> >I heard about a 650 amp version, but never seen it
> for sell
> >
> >Philippe
> >
> >Et si le pot d'échappement sortait au centre du
> volant ?
> >quel carburant choisiriez-vous ?
> > http://vehiculeselectriques.free.fr
> >Forum de discussion sur les véhicules électriques
> >http://vehiculeselectriques.free.fr/Forum/index.php
> >
> >
> >----- Original Message -----
> >From: "Robert Chew" <[EMAIL PROTECTED]>
> >To: <[email protected]>
> >Sent: Thursday, August 18, 2005 12:24 AM
> >Subject: Alltrax Controller
> >
> >
> > > HI all,
> > >
> > > Just in the process of converting my Fiat 126
> into electric drive. I
> >really really want to use the Alltrax 7245
> controller, 72 volts at 450 amps
> >because its got an rs232 port to monitor and data
> log the parameters. I am
> >doing my thesis on it. I know its cheap, i would
> like anyones thoughts on
> >it. Also i'll give my specs of the car i am
> converting. It will weigh 750
> >kg
> >all up, using Trojan SCS25 12 volts batteries, Uses
> a 6.7 inch advanced dc
> >motor the K series, and running a 4 speed box with
> no clutch.
> > >
> > > Cheers
> > >
> >
>
>
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--- End Message ---
--- Begin Message ---
Paul,
I bought two Prestolite motors at an auction, but know nothing about them. The
one has no data sticker because it was worn off the other one has really
limited information. If I sent you pictures, do you think you could identify
them and tell me whether they might be adequate to drive and EV? I also have
another huge DC electric motor that may or may not be a Prestolite - no
markings on it whatsoever. I believe they all came out of forklifts...
"Paul G." <[EMAIL PROTECTED]> wrote:
On Aug 18, 2005, at 10:52 PM, Jim Husted wrote:
> Ive recently landed some really nice used 9 inch Advances and
> Prestolites and will probably throw the Prestolites Does anyone out
> there use Prestolites?) into my project and modify and sell the
> Advances. In fact either is just as good, and I will hope to prove
> that if I can get my project off the ground. I was born and bred
> Prestolite and well Im partial to many of their models also.
I'm a bit partial to Prestolites. Both EVs I've built have been powered
by Prestolite MTC-4000 series motors. I have a nice old one with the
aluminum ring instead of the finned end bell protecting the fan. The
brush end bell was never drilled for mounting. Its pretty hanging out
of the back of my beach buggy.
Paul "neon" G.
--- End Message ---
--- Begin Message ---
But you can do regen simply with a shunt (aka Sepex) motor, Mark
>
> ----- Original Message -----
> From: "Peter VanDerWal" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Friday, August 19, 2005 9:09 AM
> Subject: Re: Help me decide!
>
>
> > >>A big advantage to brushed DC motors is how easily they will share the
> > >>load when all run from the same controller. So you really don't need 4
> > >>separate controllers; a single one large enough for the total power
> > >>needed would be a better solution.
> > >>
> > >>
> > > My only question with this was regen. I know with four seperate
> > > controllers, regen wouldn't be a problem - but what about four motors
on
> > > one controller?
> >
> > If you REALLY want regen, then go with an AC system. Getting efficient
> > Regen form DC systems requires fairly complicated motors and
controllers.
> >
> > You can get regen from an Etek, but in order to do it you have to put
the
> > brushes in a neutral posistion. This reduces the efficiency of the
motor
> > when running normally. In fact you will probably end up loosing more
> > energy from this efficiency loss then you will make up in Regen.
> >
> > About the only way to avoid this problem with brushed DC motors, is to
> > make a remote controlled, moveable, brush rigging. Not an easy task.
> >
> > AC motors don't have brushes and can therefor regen as efficiency as
they
> > motor.
> >
> > However, unless you do a lot of stop and go, or hills, regen won't add
all
> > that much range.
> >
> > > Is the 48v system such a downfall if backed by a large number of amps
in
> > > the pack? Instead of having a higher voltage pack, have a lower
voltage
> > > super-buddy paired pack?
> >
> > Low voltage and high currents = heavier cables and (generally) higher
I2R
> > losses. Higher voltage generally = higher efficiency = more range.
> >
> > >>8-volt batteries are a compromise; something you use when neither
range,
> > >>nor life, nor cost, nor performance are your biggest concerns. If
range
> > >>is your big issue, then I'd start with 6v golf car batteries like the
> > >>T-125 or T-145. See how many the vehicle can carry, and what system
> > >>voltage that leads you to.
> > >>
> > >>
> > > I'm curious why 8-volt is a compromise? Cell composition? They just
> > > seemed to work well for price, weight, and number of amp-hours.
> >
> > Yup. They have fewer plates per cell and don't handle current nearly as
> > well as 6V batteries.
> > However, I think the biggest problem with 8V GC batteries is that people
> > try to use them just like they would use 6V batteries. I.e. they make a
> > 120V pack of 8V batts (15 batteries) and expect it to perform like a
120V
> > pack of 6V batts (20 batteris).
> > 8V batteries are only good for about 200-250 amps, 6V are good for at
> > least 350-400.
> > Then they tend to drive the vehicle to the same or similar range. Since
> > the 8V pack has less lead, this means they discharge it deeper.
> > So if you select an 8V pack and then routinely pull 300-350 amps from
it,
> > and routinely drain it to 80% DOD, the batteries die quickly, typically
> > within a year.
> > I suspect that if they made a 160V pack of 8V batteries and kept the
> > battery current down to 200 amps, they would last almost as long as 120V
> > worth of 6V batteries.
> >
> >
> > >
> > >>Then look for a single traction motor large enough for the power
needed.
> > >>
> > >>Then find a controller suitable for the pack voltage and current the
> > >>chosen motor will need.
> > >>
> > >>
> > > I'm looking at alternatives, the concept of using a motor per wheel
has
> > > always been on my mind, and I thought I'd throw it out. Thanks,
again!
> >
> > All else being equal, a single large motor tends to be more durable and
> > more efficienct than multiple smaller motors.
> >
>
--- End Message ---
--- Begin Message ---
I'm not sure what the weight is on a Camry, my mother-in-law has one
and it's a boat, must weight quite a bit. I've seen some conversions
of Cherokee's and even some vans so I know it's doable, the only thing
would be how many and where to place the batteries. A 9" ADC with a
Zilla would certainly move that beast, but it depends on what range
you are looking for. Also of note and someone may correct me if I'm
wrong, but the Toyota RAV4 is based on the Camry and they successfully
produced RAV4EV, although most are now being taken back by Toyota. So
in essence you should be able to do it, but again it all boils down to
the batteries and placement.
hope this helps.
Stefano
On 8/19/05, Cwarman <[EMAIL PROTECTED]> wrote:
>
> Also found a good deal on a 99 Camary for sale with a blown motor....Is
> this car to heavy for a good conversion ?
>
> Cwarman
>
> >
>
>
--- End Message ---
--- Begin Message ---
> But you can do regen simply with a shunt (aka Sepex) motor, Mark
Do you know of a source for readily available Sepex motors and controllers
that can match the efficiency of AC systems?
>> > > My only question with this was regen. I know with four seperate
>> > > controllers, regen wouldn't be a problem - but what about four
>> motors
> on
>> > > one controller?
>> >
>> > If you REALLY want regen, then go with an AC system. Getting
>> efficient
>> > Regen form DC systems requires fairly complicated motors and
> controllers.
--- End Message ---
--- Begin Message ---
I see the Camary has a gross weight of about 3100 lbs compared to a Neon
with 2585 and a S-10 pick up as 4200lbs and my last choice is a kia
sportage 4278
Cwarman
Stefano Landi wrote:
I'm not sure what the weight is on a Camry, my mother-in-law has one
and it's a boat, must weight quite a bit. I've seen some conversions
of Cherokee's and even some vans so I know it's doable, the only thing
would be how many and where to place the batteries. A 9" ADC with a
Zilla would certainly move that beast, but it depends on what range
you are looking for. Also of note and someone may correct me if I'm
wrong, but the Toyota RAV4 is based on the Camry and they successfully
produced RAV4EV, although most are now being taken back by Toyota. So
in essence you should be able to do it, but again it all boils down to
the batteries and placement.
hope this helps.
Stefano
On 8/19/05, Cwarman <[EMAIL PROTECTED]> wrote:
Also found a good deal on a 99 Camary for sale with a blown motor....Is
this car to heavy for a good conversion ?
Cwarman
.
--- End Message ---
--- Begin Message ---
Also price is a concern and the Zilla costs alot doesnt it compared to a
Curtis ?
Cwarman
Stefano Landi wrote:
I'm not sure what the weight is on a Camry, my mother-in-law has one
and it's a boat, must weight quite a bit. I've seen some conversions
of Cherokee's and even some vans so I know it's doable, the only thing
would be how many and where to place the batteries. A 9" ADC with a
Zilla would certainly move that beast, but it depends on what range
you are looking for. Also of note and someone may correct me if I'm
wrong, but the Toyota RAV4 is based on the Camry and they successfully
produced RAV4EV, although most are now being taken back by Toyota. So
in essence you should be able to do it, but again it all boils down to
the batteries and placement.
hope this helps.
Stefano
On 8/19/05, Cwarman <[EMAIL PROTECTED]> wrote:
Also found a good deal on a 99 Camary for sale with a blown motor....Is
this car to heavy for a good conversion ?
Cwarman
.
--- End Message ---
--- Begin Message ---
I really would like to get 50miles and top speeds of 65 are fine...
Cwarman
Stefano Landi wrote:
I'm not sure what the weight is on a Camry, my mother-in-law has one
and it's a boat, must weight quite a bit. I've seen some conversions
of Cherokee's and even some vans so I know it's doable, the only thing
would be how many and where to place the batteries. A 9" ADC with a
Zilla would certainly move that beast, but it depends on what range
you are looking for. Also of note and someone may correct me if I'm
wrong, but the Toyota RAV4 is based on the Camry and they successfully
produced RAV4EV, although most are now being taken back by Toyota. So
in essence you should be able to do it, but again it all boils down to
the batteries and placement.
hope this helps.
Stefano
On 8/19/05, Cwarman <[EMAIL PROTECTED]> wrote:
Also found a good deal on a 99 Camary for sale with a blown motor....Is
this car to heavy for a good conversion ?
Cwarman
.
--- End Message ---
--- Begin Message ---
Lee,
I don't know what is the term for it here, but I'm sure you know
what I'm talking about. I had relays with zero holding current.
They are "flipping" types, basically the principle is to
link a solenoind to a regular toggle switch. Once toggled
and machanically latched, you remove the current from the coil
- itis no longer meeded. To turn off - there are two flavors
of this device - one with another coil on the opposite side,
and other - wuth permanent magnet in the solenoid, in which
case you just reverse polarity on the same coil.
If big enough, a mechanically latching contactor
can be constructed. Major draw back is, it will stay on
if the power goes out or fuse blows - you cannot
electrically turn it off anymore. But if on
the separate circuit, just a relay coil is very reliable
thing.
For some reason I don't see such devices in the USA.
May be I don't hbow how to ask for them. Do you know
by chance the technical term for this relay type?
Victor
Lee Hart wrote:
Neon John wrote:
An economizer is typically a cap and a resistor in parallel, hooked in
series with the coil.
Good description of the most common kind of economizer circuit.
John Wayland described another type. The resistor and capacitor are in
series. The switch and coil are in series, and connected across the
capacitor. When the switch is off, the capacitor charges up thru the
resistor. When the switch turns on, the capacitor discharges into the
coil, rapidly pulling it in. But then the capacitor runs down, and the
resistor determines the steady-state holding voltage (which is usually
around 1/4th the supply voltage). This circuit is less popular because
it requires a bigger, higher voltage capacitor and you need connections
to both sides of the switch (neither side can connect to +12v or
ground).
The high-tech circuits described by Roger Stockton also work. They cost
more and take more design effort, but get rid of the power resistor and
the heat it produces, and are thus more efficient.
There are still other methods. The cheapest is a light bulb in series
with the coil. Its resistance when cold is very low, so the coil pulls
in with essentially full voltage. But then the bulb lights, its
resistance rises, and it limits the current. With the kilovac, I'd try
an normal car brake+tail light with both filaments in parallel.
Another efficient method (not applicable in this case) is to use a 24v
coil contactor with a 12v circuit. You also need a big capacitor, a
diode, and a DPDT switch. With the switch off, it connects the capacitor
to the 12v source and the coil is open (off). When you turn the switch
on, it connects the charged capacitor and the 12v source in series to
power the coil at 24v. When the capacitor runs down, a diode maintains
the coil current from the 12v source. This scheme eliminates any power
wasting resistors, but requires a more complicated switch.
There are still more, but they are special-case solutions (like
contactors with separate actuate and hold coils).
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Thanks Claudio,
Would someone mind pointing out some good references that would help me
understand such arcane subjects as "useful discharge rate"
Thanks,
Noel
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Claudio Natoli
> Sent: Thursday, August 18, 2005 11:55 PM
> To: [email protected]
> Subject: RE: 100 mile range, Re: Alternative batteries
>
>
> Peter writes:
> > > 200ah cells should be minimum size for any ev or you will
> run into
> > > problems with available power not capacity.
>
> Noel writes:
> > How did GM get good acceleration and range with their Ovonic 13.2v
> > 85Ah NiMH batteries?
>
> Different chemistry.
>
> Peter and Victor were discussing 200Ah cells as a minimum in
> the context of *Lithium Ion* batteries, which have a lower
> useful discharge rate (relative to cell size) than the other
> common battery chemistries.
>
> Cheers,
> Claudio
>
>
This e-mail and any attachments may contain confidential and privileged
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--- Begin Message ---
awhile back I changed out the 25 golf cart bats in my work truck , I planed
to put the old truck batteries in the Toyota torcell project which I have in
Okeechobee 30 miles away . I figured this would be a good time to do a 100
mile run and get in the www.grassrootsev.com 100 mile on a charge club. I
loaded up the truck with the , still good batteries and wired the two packs
in parallel. The plan was to drive to Okeechobee then back to Fort Pierce
where I live then back again , and do a extra 10 miles to make the 100, . I
had no problem about having enough juice , and with the batteries pushed as
far forward in the bed the truck drove fine at 40 to 50 mph / drove mostly
at about 40 pulling 80 amps and ended using about 180 ah and a voltage over
11v with load. Jon an old friend of mine , and the web master nailed me
with one small detail , Okeechobee is 10 miles lower than Fort Pierce and as
I drove there twice but back only once I was going down hill more than up
:-( . I would have been ok if I had gone 50 miles one way and then back or
25 miles 4 times .
Steve Clunn
--- End Message ---
--- Begin Message ---
Sam Harper wrote:
> I'm not really interested in the 4WD system itself - in fact, it
> will be removed. I really just want the wheel hubs/axles from the
> 4WD system for use with the Eteks.
Ok, I understand. If you want a motor-per-wheel system, you'll need a
suitable gearbox for each motor. If you're going to mount the motor
itself to the wheel, the challenge will be to find a gearbox and motor
that can stand the shock and vibration, and yet is light enough not to
seriously degrade handling. Cooling them may also be difficult; they
have to be sealed enough to keep out water and dirt, but get enough
airflow to stay cool. With a fixed-gear-ratio setup, the motors get very
hot if operating at high torque and low speed (crawling up a long hill,
for example).
Or, you can mount the motors and gear reducers inboard, connected with
half-shafts and universal joints. Now they can be bigger and heavier
without impacting handling. They also don't need to be as rugged, as the
shock and vibration loads are less. Cooling is much easier. But now you
need lots of room for these parts.
One option might be to use hydraulic wheel motors. They are smaller,
lighter, cheaper, naturally sealed from the environment, and easily
cooled (the oil carries the heat away). No gearboxes are needed. You
then use one large motor and hydraulic pump to power them all. The
drawback is they are less efficient than gearboxes; probably 80% vs.
95%.
> You are correct, the Etek has its weaknesses - my main concern is
> whether it is strong enough.
A "traction" motor is specifically designed to deliver extremely high
peak power, and extremely high starting torque -- easily 10 times its
normal continuous duty ratings. The industrial-grade traction motors are
also expected to work all day every day for decades. Thus, they are
"overbuilt" with stronger, heavier parts, and longer-lasting bearings
and brushes.
More normal motors (like the Etek) are only built to supply 2-3 times
their normal continuous-duty ratings. They also "cheapen" them to not
last as long -- just long enough to satisfy whatever the intended
application requires. Customers won't pay for a 100,000 hour motor for a
100 hour application.
But many EVs aren't driven all that much. They are a second car, and
used for shorter trips. So shorter motor life may not be a problem. You
can also oversize the motor (like 4 Eteks in a car where 2 Eteks might
have appeared adequate), so you still have enough peak load capability
without breaking them.
Another option might be to use 4 golf cart motors; far cheaper, but they
are built as traction motors and would probably last longer. Lower
efficiency, though -- 80% versus 90%.
Still another option might be a hybrid drive. Use a large tractiom motor
for peak power (faster accelleration and hillclimbing), and a smaller
efficient motor for cruising (like Eteks).
> I know with four seperate controllers, regen wouldn't be a problem
> - but what about four motors on one controller?
Still not a problem. With brushed DC motors, the controller can't tell
the difference between one big motor or several smaller ones in series
or parallel. Both motoring and regen work the same.
Motors in series act exactly like a normal car differential. Same torque
at both wheels (because both motors have exactly the same current). But
the wheels can turn at different speeds -- good for going around
corners, but bad if one wheel is on ice or up in the air.
Motors in parallel work independently, and act like a limited slip
differential. They both try to run at the same speed (because each has
the same voltage). When you go around a corner, the inside wheel slows
down a bit, and so draws more current and makes more torque. The outside
wheel speeds up a bit, so draws less current and makes less torque.
> Is the 48v system such a downfall if backed by a large number of
> amps in the pack? Instead of having a higher voltage pack, have
> a lower voltage super-buddy paired pack?
Right; as long as you pick the motor and controller to suit the pack
voltage, then pack voltage makes no difference in accelleration or
range.
All I meant was that if you happen to need 1000 lbs of batteries to get
your desired range, and you want to use golf cart batteries for their
low price, that leads to 1000 / 62 = 16 batteries. The easiest way to
wire them is in all in series, which gives you a 16 x 6v = 96v system.
It's easy to find a single charger, motor, and controller of adequate
power for this system.
But you could also wire them as two strings of 8 in parallel, for a 48v
system. Double the current at half the voltage is the same power, and
same range. But it will be a little harder to wire (more pieces of
heavier wire due to the higher currents). It's a little harder to find a
48v high-current charger, but they exist (used for big industrial EVs).
There may be some balancing issues if one string develops a bad battery,
or one string is colder than the other due to its mounting arrangement.
Lower-voltage higher-current motors and controllers aren't too hard to
find, but are a bit bigger and heavier (ultra-conservatively built
forklift stuff). These problems aren't hard to deal with, but they
require additional thought and work.
>>> 4 strings of 6 US Battery 8-volt HC batteries
>> 8-volt batteries are a compromise; something you use when
>> neither range, nor life, nor cost, nor performance are your
>> biggest concerns.
> I'm curious why 8-volt is a compromise? Cell composition? They just
> seemed to work well for price, weight, and number of amp-hours.
Flooded lead-acid batteries come in a wide range of characteristics. In
general you will find:
6v: cheap, long life, high capacity at low currents
large voltage sag under load, low capacity at high currents
6v are a "go far" battery for heavy, slow, long range EVs
8v: moderate cost, moderate life, moderate capacity at low rates
moderate voltage sag, moderate capacity at high currents
12v: expensive, low life, low capacity at low discharge rates
less voltage sag, high capacity at high discharge rates
12v are a "go fast" battery for light, fast, short range EVs
Usually people have one or two requirements that they feel they must
meet. They pick their batteries accordingly.
8v are the choice if there is no one requirement that you need to
maximize. Usually, they are a good choice if you already have your motor
and controller, and they determine the pack voltage you need, and the
space available for batteries leads you to 8v per battery.
Since floodeds cannot provide long range *and* high performace
simultaneously, people switch to some other battery type if they need
both. Cost then goes up substantially -- there's a big jump up in price
when you move away from flooded lead-acids.
> I'm looking at alternatives, the concept of using a motor per wheel has
> always been on my mind, and I thought I'd throw it out. Thanks, again!
It's an interesting idea. If you're mechanically inclined, why not give
it a try!
--
Every act of conscious learning requires the willingness to suffer an
injury to one's self-esteem. That is why young children, before they
are aware of their own self-importance, learn so easily. - Thomas Szasz
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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Mark Hanson wrote:
> On a series motor, known current is fed through the field and a voltage drop
> is measured, calculating the microhm resistance. Then an equal resistance is
> set up & measured through the contactor used using #12 wire into an air coil,
> usually ends up being 1-2' long with the field weakening contactor. Typically
> 20% more of base speed.
Yes, that sounds like excellent advice. I like Bodine motors, and they
still have some pretty sharp applications engineers. Pricey, though.
--
Every act of conscious learning requires the willingness to suffer an
injury to one's self-esteem. That is why young children, before they
are aware of their own self-importance, learn so easily. - Thomas Szasz
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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My motor will be in in the next couple of weeks.
I am trying to save some time by just finding someone to make me up a taperlock
hub that I can have drilled on the flywheel(starter ring) side to fit my
transmission at a local machine shop. I notice on at least one website they
offer pre-machined hubs for S-10,s etc. My need is simpler. I need even less.
The pre-made ones seem to be $200 or so. I am just trying to save the time it
will take to fool with the taperlock.
If anyone can suggest a supplier that would just send me one cut a little
longer than I need it and the right diameter, I would appreciate it. I will be
cutting out my profile plate and will make the motor spacer after I get the hub.
If the above is not likely, something specific about the type of bushing &
holder (and a supplier that someone has dealt with) that can be machined into a
4" piece of 4130 barstock I have on hand.
If you look at my Blog, there is a picture of the transaxle I am using.
I should then only need the bolt holes tapped, a clearance hole for the torque
converter pilot shaft and a turn down for the hole in the spring plate to line
everything up.
Motor is a Netgain Warp 9" Impulse
Suggestions appreciated!
Mark Ward
95 Saab 900
www.saabrina.blogspot.com
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Peter VanDerWal wrote:
> If you REALLY want regen, then go with an AC system. Getting
> efficient Regen from DC systems requires fairly complicated
> motors and controllers.
Not at all! Granted, you can't get good regen from the cheapest motors
and controllers. But you can't with AC either. If you know you want
regen, the motor and controller both need to be designed with this in
mind. That makes them a bit more complicated and more expensive, but not
drastically so.
> You can get regen from an Etek, but in order to do it you have to
> put the brushes in a neutral posistion. This reduces the efficiency
> of the motor when running normally. In fact you will probably end
> up loosing more energy from this efficiency loss then you will make
> up in Regen.
No; I would say the efficiency difference between neutral brush position
and the optimum for motoring is ony 1-2%. The higher the efficiency of
the motor, the closer these two are to the same.
> About the only way to avoid this problem with brushed DC motors
> is to make a remote controlled, moveable, brush rigging.
No; moving the brushes is 100-year-old technology. The standard way to
get good performance as both motor and generator is to use compensating
windings (interpoles, pole face windings, etc.)
Hobbyists move the brush rigging because it is easier to do on a motor
that is already made without interpoles.
PM motors have much less trouble with the need to change brush timing
because they always operate at full field strength.
> Low voltage and high currents = heavier cables and (generally)
> higher I2R losses.
You get higher I2R losses if you *don't* increase the cable sizes. If
you *do*, then the I2R losses are the same.
> Higher voltage generally = higher efficiency = more range.
It depends on what you hold constant, and what you change to suit the
voltage and current.
> I think the biggest problem with 8V GC batteries is that people
> try to use them just like they would use 6V batteries. I.e. they
> make a 120V pack of 8V batts (15 batteries) and expect it to
> perform like a 120V pack of 6V batts (20 batteries).
Yes. Kinda like expecting fewer horses to pull the same load but eat
less. You wind up overworking them.
--
Every act of conscious learning requires the willingness to suffer an
injury to one's self-esteem. That is why young children, before they
are aware of their own self-importance, learn so easily. - Thomas Szasz
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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Peter, Bob, Don, Bruce,
Thanks for the Titles
John J Januszewski
www.jcomposites.com
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Lee Hart wrote:
Imagine that *you* are the charger controller. Suppose I placed a heavy
cardboard box with two wires hanging out of it on your desk and said,
"Victor, charge this battery." How would you do it?
This is interesting Lee, but I'm suspecting a user at least
knows what chemistry battery he deals with.
If you put a blsck box in front of me saying "Charge" it,
in theory first I need to know if there is really a battery
in it. If I measure 0V it can be:
- nothing in the box, wires just hanging
- nothing in the box, wires shorted
- totally dead battery (0V) if unknown chemistry/capacity.
That battery can be dead 1.2V NiCd cell or can be
574V one (dead Zebra battery) or series/parallel connection of
who knows what with different chemistries mixture.
Asking for the charger intelligence to determine all that
is doable but no one will buy such a charger. And, realistically
it is not nesessary.
I'm assuming reasonable user knows what battery he connects charging
device to and what to expect from a known good battery
*of that type*, so you have basis for judgement.
The problem is that the "best" charging algorithm CHANGES depending not
only on the particular type and model of battery, but also on its
condition and recent history. A charger that always applies the same
algorithm will be right sometimes, and wrong other times.
Yes, I know that Lee. It is not really a problem. The problem is
there is no empirical data for adjustments needed per all these
conditions. Everyone knows it changes. Formalize in numbers how.
Compensation for the temp, amount of cycles (age) average DOD during
use ("abuse factor") can all *Easily* be implemented using look up tables.
Give me the hard number for each condition and I'll get
you such a charger.
It is not difficult to get numbers empirically - you run enough samples
with the conditions you're interested in, and record the outcome.
The problem is it will take hundreds of thousands of batteries and 50 years
or so of continuous testing to cover all combinations. So
no one has even basic hard numbers such as:
How much (%) do you recuce voltage in absorbtion phase as the
battery gets older (say per each 100 (50%DOD) cycles)?
Is it really cycles, or total Ah through the battery?
(10%DOD "cycle" is very different from 90%DOD one).
Even if you come up with that number, what is its dependency
on average DOD this battery experienced during its life?
The harger battery worked the more you must reduce
absorbtion voltage per every 10,000Ah gone through it
even if calendar life is shorter? If so how much more?
I know you have no answers - no one does. Making
gadget performing as specified is much much easier
then specify correctly what you want.
So, in reality, it is far less expensive to best guess
and still kill the battery prematurely (compared to magic
ideal use) keeping replacing it, than conduct this massive
research and asquiting billions of terabytes of data
to find out that ideal.
So all I'm asking is that formalized best guess.
Rich suggested one.
Peter suggested another.
Optima still may suggest something else.
I can average them all or try to guess myself, but
I know far less abour lead that any of them.
If you want to reach full sooner, you need to apply a higher voltage or
more current. But how much more? You have to guess. Here are some ideas:
- Apply a higher voltage for a fixed length of time. For instance,
1-2 hours at 2.5v/cell or 15v is usually enough to reach full for a
good battery that isn't too old or too cold.
15V hard no matter what the current is? or fixed current but
clamped to 15V voltage?
- Apply a low current for a fixed time. For instance, 2-4 amps per
100ah of capacity. What you're trying to do is put in an extra
2% to 4% more amphours to allow for the charge efficiency being]
less than 100%. But for this to work, you need to know the battery's
actual amphour capacity.
This is actuallu easiest method since measurable. I can always
add, say, 3% more.
- More than capacity, or 3Ah per 100Ah of the batTery?
- Or 3% more than spent during last discharge?
- Is it still 3% whether I push 2A for 1.5hrs or 1A for 3 hrs?
- Is it still 3% for new batery and cycled one?
- For an old one do I increase this percentage keeping
current the same longer, or increasing current keeping
the same time?
How does this all drift with the temperature?
I realize I won't get an answers. But the gadget
has adjustment constants defaulting to "1" waiting
to be changed. What do I do, leave it at "1" because
I don't know any better and have customer to deal with
consequences?
- Call me, and find out how many amphours I took out. Add 2% to 4%,
and keep putting in power (and any reasonable voltage and current)
until that many amphours are returned. This is Hawker's 6-hour
charging algorithm. Few chargers actually do it, because they don't
actually know the amphours removed.
I know Ah removed. Does returning only 2-4% of what was taking out
and mo more guarantees the battery can't possibly get
undercharged/overcharged?
- Keep charging until the voltage stops rising, or the current stops
falling. It works by assuming that the battery temperature will
start to rise when it reaches full, and this will cause the charging
voltage and/or current to change the direction it was moving in.
Also assuming sealed battery won't vent. Should I factor in
manufacturing quality too?
This is the dv/dt or di/dt algorithm used in many large industrial
chargers. It works best for batteries that can tolerate mild
overcharging on a routine basis, like floodeds.
And there are lots more. Pulsing chargers, alternating charge/discharge
algorithms, ones that actually discharge the battery first so the
charger knows what state it is in, etc. Then there are algorithms that
assume something is wrong with the battery, and attempt to correct for
it. They are usually too brutal to do for every cycle, but may be
necessary once in a while for abused batteries.
Thanks, this is very educational and entertaining, but I'm
still where I started - no real data to enter in.
--
Victor
'91 ACRX - something different
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