EV Digest 2857
Topics covered in this issue include:
1) EV icecream truck
by "1sclunn" <[EMAIL PROTECTED]>
2) Re: wheel motor
by Peter VanDerWal <[EMAIL PROTECTED]>
3) Re: This is a MUST READ LA Times Article
by "1sclunn" <[EMAIL PROTECTED]>
4) 1000 amp Emeter wanted
by Seth Murray <[EMAIL PROTECTED]>
5) RE: EV icecream truck
by [EMAIL PROTECTED]
6) RE: EV icecream truck
by "sae" <[EMAIL PROTECTED]>
7) Re: wheel motor
by Evan Tuer <[EMAIL PROTECTED]>
8) Re: Evercel MB80 cycling
by Rich Rudman <[EMAIL PROTECTED]>
9) Re: 1000 amp Emeter wanted
by Rich Rudman <[EMAIL PROTECTED]>
10) 1971 VW Beetle custom Electric conversion on eBay
by "The Levine Family" <[EMAIL PROTECTED]>
11) Re: EV1 vs Prizm...
by "Tim Clevenger" <[EMAIL PROTECTED]>
12) RE: Evercel MB80 cycling
by "Tom Hudson" <[EMAIL PROTECTED]>
13) Re: EV1 vs Prizm...
by FRANK GIANNANDREA <[EMAIL PROTECTED]>
14) Re: EV1 vs Prizm...
by FRANK GIANNANDREA <[EMAIL PROTECTED]>
15) Re: wheel motor
by Peter VanDerWal <[EMAIL PROTECTED]>
16) Re: Evercel MB80 cycling
by "Jon \"Sheer\" Pullen" <[EMAIL PROTECTED]>
17) Ultralife or Avestor
by "Coallier, Steve" <[EMAIL PROTECTED]>
18) Re: Li Ion Charge Curve
by Victor Tikhonov <[EMAIL PROTECTED]>
19) Re: Amps and amp hours
by Victor Tikhonov <[EMAIL PROTECTED]>
20) Re: S-10 conversion advise
by Victor Tikhonov <[EMAIL PROTECTED]>
21) Re: Independent Drive System
by Victor Tikhonov <[EMAIL PROTECTED]>
22) Re: Starting torque
by Victor Tikhonov <[EMAIL PROTECTED]>
23) Re: Wheelmotors
by Lee Hart <[EMAIL PROTECTED]>
24) CVT and question about clutch
by Jeff Shanab <[EMAIL PROTECTED]>
25) Re: Lowest frequency (was Re: AC vs DC)
by Lee Hart <[EMAIL PROTECTED]>
26) Re: S-10 conversion advise
by Peter VanDerWal <[EMAIL PROTECTED]>
27) Re: Wheelmotors
by "Eric Penne" <[EMAIL PROTECTED]>
28) Re: Evercel MB80 cycling
by Victor Tikhonov <[EMAIL PROTECTED]>
29) Re: wheel motor
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Jon who is not on the list but should be ( drives one of my conversions )
has put together this proposal for his boss who is looking to replace there
Ice-cream truck. below
Project Proposal Summery
Commercial Delivery Truck Hybrid Electric Conversion
Mobile Mike's Ice Cream Truck
This vehicle can serve as an events power plant for powering electrical
power tools,
air conditioning, lighting, appliances, public address systems etc.
for catering, construction projects stage shows etc. As well as a delivery
truck.
Mobile Mike's Ice Cream Truck
First we will locate our candidate; a class 2 commercial vehicle 4,000 to
6,000 lbs with manual transmission typical gas mileage is less than 10 mpg.
It should be in fairly good condition except for its engine. We will remove
the engine and replace it with two electric motors and components,
converting it to an electric vehicle. We project that it should have a range
of over forty non polluting clean economical miles at speeds averaging
between 45 to 85 mph before it needs to be recharged.
Components;
1. Two DC electric motors
2. New leading edge controller that is four times more powerful than its
predecessors.
3. A bank of 26 x 12 volt deep cycle lead jell acid, maintenance free,
batteries. Custom constructed light weight fiberglass battery boxes
4. The batteries will be charged utilizing our new advanced lightweight
powerful PFC battery charger.
5. Powerful DC to AC inverter to be able to run appliances with quiet clean
power for up to eight hours.
6. 15kw LP, gas or diesel generator can be mounted or removed depending on
its application or the vehicle's application.
This generator can charge the batteries as you drive making this a hybrid
vehicle.
I pointed out that 85 mph was a lot to ask (60 mph seem's better to me ) ,
also at 40 miles with truck this size ( that's just about what my lawn truck
and trailer weights ) . Jon say that's what the gen is for . I'm also
thinking this would be better with victor's ac motor but would like to try
one of Otmar's controller's out also . Being able to run 120/240 stuff is
very important to him . I had two ideas . 1 a small bank of 48v being
charged from the big batteries bank with a PFC-20 and a invertors , 2 find
someone to build a invertors that runs off the high voltage bank (nobody
seem interested in doing this so no 1 is top on this list) . Jon say the
radio station uses it at events so there is not a lot of driving around
selling ice-cream . Jon say his boss has money to spend , 1/4 mil buss and
hummers ect.
Maybe just a 48v /16 golf cart cart in a gasser with PFC charger and 2k
inverter . No fun there. I'll froward any ideas to jon
Steve Clunn
--- End Message ---
--- Begin Message ---
> LOL. Actually the Insight CVT is pretty good (for a CVT). The belt
> drive CVTs, like they use in ATVs. is what I've been talking about. A
> belt drive CVT approaches 90% efficient...at a 1:1 ratio. At anything
> other than 1:1 the efficiency drops off.
>
Oops, tired last night. I forgot to mention; CVTs approach 90% at 1:1
when transferring MAX power. The losses in a CVT are due to friction
and friction remains nearly constant (at a given ratio) regardless of
power. At lower power levels efficiency drops because the losses stay
the same and now represent a larger portion of the input power.
The numbers I posted last night were for a CVT operating near maximum
power. Reality is that the CVT will normally be operating at power
levels far from maximum and this is why the average efficiency from a
CVT is around 50% or less.
--- End Message ---
--- Begin Message ---
I copyed it and am passing it around . Also there is a lot of good info that
comes and goes on the list , I'd like to post some of it on the
www.grassrootsev.com web site then when I get the question like " what's the
best way to charge my batteries " I could say go to yyyyy. Do I need to ask
, Lee , Rich , Joe , John ect , . Would be glad to give you the credit ,
seems like alot of this info should be spread around .
----- Original Message -----
From: "Bruce EVangel Parmenter" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, June 15, 2003 9:31 PM
Subject: Re: This is a MUST READ LA Times Article
> Already POSTed
> http://autos.groups.yahoo.com/group/ev-list-archive/message/3071
>
> =====
> ' ____
> ~/__|o\__
> '@----- @'---(=
> http://geocities.com/brucedp/
> EV List Editor & RE newswires
> (originator of the above ASCII art)
> =====
>
> __________________________________
> Do you Yahoo!?
> SBC Yahoo! DSL - Now only $29.95 per month!
> http://sbc.yahoo.com
>
--- End Message ---
--- Begin Message ---
anyone out there have a 1000 amp Emeter they want to sell me? thanks
Seth
--
QUESTION INTERNAL COMBUSTION
http://users.wpi.edu/~sethm/
--- End Message ---
--- Begin Message ---
Steve,
Shouldn't his proposal consistantly read "miles" or "MPC (miles per charge)"
[range] instead of "mph", which means miles per hour [speed]?
-Ed
-----Original Message-----
From: 1sclunn [mailto:[EMAIL PROTECTED]
Sent: Monday, June 16, 2003 10:09 AM
To: Jon Hallquist; [EMAIL PROTECTED]
Subject: EV icecream truck
Jon who is not on the list but should be ( drives one of my conversions )
has put together this proposal for his boss who is looking to replace there
Ice-cream truck. below
Project Proposal Summery
Commercial Delivery Truck Hybrid Electric Conversion
Mobile Mike's Ice Cream Truck
This vehicle can serve as an events power plant for powering electrical
power tools,
air conditioning, lighting, appliances, public address systems etc.
for catering, construction projects stage shows etc. As well as a delivery
truck.
Mobile Mike's Ice Cream Truck
First we will locate our candidate; a class 2 commercial vehicle 4,000 to
6,000 lbs with manual transmission typical gas mileage is less than 10 mpg.
It should be in fairly good condition except for its engine. We will remove
the engine and replace it with two electric motors and components,
converting it to an electric vehicle. We project that it should have a range
of over forty non polluting clean economical miles at speeds averaging
between 45 to 85 mph before it needs to be recharged.
Components;
1. Two DC electric motors
2. New leading edge controller that is four times more powerful than its
predecessors.
3. A bank of 26 x 12 volt deep cycle lead jell acid, maintenance free,
batteries. Custom constructed light weight fiberglass battery boxes
4. The batteries will be charged utilizing our new advanced lightweight
powerful PFC battery charger.
5. Powerful DC to AC inverter to be able to run appliances with quiet clean
power for up to eight hours.
6. 15kw LP, gas or diesel generator can be mounted or removed depending on
its application or the vehicle's application.
This generator can charge the batteries as you drive making this a hybrid
vehicle.
I pointed out that 85 mph was a lot to ask (60 mph seem's better to me ) ,
also at 40 miles with truck this size ( that's just about what my lawn truck
and trailer weights ) . Jon say that's what the gen is for . I'm also
thinking this would be better with victor's ac motor but would like to try
one of Otmar's controller's out also . Being able to run 120/240 stuff is
very important to him . I had two ideas . 1 a small bank of 48v being
charged from the big batteries bank with a PFC-20 and a invertors , 2 find
someone to build a invertors that runs off the high voltage bank (nobody
seem interested in doing this so no 1 is top on this list) . Jon say the
radio station uses it at events so there is not a lot of driving around
selling ice-cream . Jon say his boss has money to spend , 1/4 mil buss and
hummers ect.
Maybe just a 48v /16 golf cart cart in a gasser with PFC charger and 2k
inverter . No fun there. I'll froward any ideas to jon
Steve Clunn
--- End Message ---
--- Begin Message ---
The new AC Propulsions drive has a 120/240v output for providing power back
to the grid. Might work for what you want.
paul
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of 1sclunn
Sent: Monday, June 16, 2003 1:09 PM
To: Jon Hallquist; [EMAIL PROTECTED]
Subject: EV icecream truck
Jon who is not on the list but should be ( drives one of my conversions )
has put together this proposal for his boss who is looking to replace there
Ice-cream truck. below
Project Proposal Summery
Commercial Delivery Truck Hybrid Electric Conversion
Mobile Mike's Ice Cream Truck
This vehicle can serve as an events power plant for powering electrical
power tools,
air conditioning, lighting, appliances, public address systems etc.
for catering, construction projects stage shows etc. As well as a delivery
truck.
Mobile Mike's Ice Cream Truck
First we will locate our candidate; a class 2 commercial vehicle 4,000 to
6,000 lbs with manual transmission typical gas mileage is less than 10 mpg.
It should be in fairly good condition except for its engine. We will remove
the engine and replace it with two electric motors and components,
converting it to an electric vehicle. We project that it should have a range
of over forty non polluting clean economical miles at speeds averaging
between 45 to 85 mph before it needs to be recharged.
Components;
1. Two DC electric motors
2. New leading edge controller that is four times more powerful than its
predecessors.
3. A bank of 26 x 12 volt deep cycle lead jell acid, maintenance free,
batteries. Custom constructed light weight fiberglass battery boxes
4. The batteries will be charged utilizing our new advanced lightweight
powerful PFC battery charger.
5. Powerful DC to AC inverter to be able to run appliances with quiet clean
power for up to eight hours.
6. 15kw LP, gas or diesel generator can be mounted or removed depending on
its application or the vehicle's application.
This generator can charge the batteries as you drive making this a hybrid
vehicle.
I pointed out that 85 mph was a lot to ask (60 mph seem's better to me ) ,
also at 40 miles with truck this size ( that's just about what my lawn truck
and trailer weights ) . Jon say that's what the gen is for . I'm also
thinking this would be better with victor's ac motor but would like to try
one of Otmar's controller's out also . Being able to run 120/240 stuff is
very important to him . I had two ideas . 1 a small bank of 48v being
charged from the big batteries bank with a PFC-20 and a invertors , 2 find
someone to build a invertors that runs off the high voltage bank (nobody
seem interested in doing this so no 1 is top on this list) . Jon say the
radio station uses it at events so there is not a lot of driving around
selling ice-cream . Jon say his boss has money to spend , 1/4 mil buss and
hummers ect.
Maybe just a 48v /16 golf cart cart in a gasser with PFC charger and 2k
inverter . No fun there. I'll froward any ideas to jon
Steve Clunn
--- End Message ---
--- Begin Message ---
Peter VanDerWal wrote:
> Let's say that you are driving around at low speed and only need about
> 1kw from the motor. Depending on the RPM efficiency will be somewhere
> around 80% +or- 5%. Motor is turning slow and voltage across it is low.
>
> Now let's use our CVT. Motor is spinning fast (that's the point of the
> CVT right?) which means high voltage but low current. Believe it or not
> this is where the LEMCO really sucks. Efficiency at high voltage/low
> current can drop to 10% or less.
Peter, I have to say that's a wee bit misleading. Any motor "sucks" when it's
approaching no-load running, that's because you're applying current to overcome
the losses and fan loading, and only getting a light breeze out.
Now, the LEMCO might be worse than a series wound motor *without* a fan in
this respect, but that's not a fair comparison.
The LEMCO double motor that's being talked about here is still above 80%
efficiency with only 1KW mechanical load at 60V, running close to it's maximum
speed. Not 10%.
Produce the same power at a low RPM (say 400) and you will in fact end up
with a much lower efficiency of about 50% as brush volt drop and I*R consume a
greater proportion of the supply voltage. Not 80%.
And, you'll probably need an external blower then as well..
Of course, you don't need to agree before you've looked at the curves:
http://www.lemcoltd.com/pdf/Lemco200D_127.pdf
Anyway, I'm not disagreeing with the point you're making - using a CVT is very
rarely going to make sense in an EV application, though I'm sure there are (or
were) exceptions.
Just my 2HP worth.
Evan.
--- End Message ---
--- Begin Message ---
fred whitridge wrote:
>
> Oops make that 69.1 amphours. I have a 50amp/50mv shunt which makes the
> readings on the eMeter 10x actual. 691 amp hours out of this little package
> would have been fine indeed! BTW this was down to the 9.6 volt shutoff
> recommended at this drain rate. 7.6 volts is the recommended cutoff for EV
> style amperages. My next discharge will be at 20 amps and I may go all the
> way up to a staggering 32 amps to get some idea of Peukert.
We did not get heating issues until we did Ev range current draws say
150 to 300 amps. Charging at 10Kw made heat but only on the first few
cycles, and things didn't really get out of hand since the test was at
50 Deg F.
Anybody got a MB80 that Joe and I could abuse test??
I will try to get one from my leads.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Seth Murray wrote:
>
> anyone out there have a 1000 amp Emeter they want to sell me? thanks
>
> Seth
>
> --
> QUESTION INTERNAL COMBUSTION
> http://users.wpi.edu/~sethm/
Does Rod at Evparts.com still have one ??
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
I can't tell whether this item is an EV conversion --
"What is being offered for this auction is the custom electric conversion of
a 1971 Volkswagen Beetle. Vim Number 1112263672, license plate number
1PLL738."
or maybe a conversion of a VW you supply --
"Custom Car Conversion Your electric Bug won't be something that you just
found for sale. Your VW EV will be something that is being made for you. You
will be able to pick the color of your new vehicle. After the electric
conversion has been finished we will give your Bug a final coat of paint to
suit your color taste."
The belly battery boxes sound unique, but a new conversion using relays
seems a buit dated -- if that's a shunt-wound motor, wouldn't a SepEx
controller make things a bit smoother, esp. since you get regen and reverse
built into the controller? Then I read:
"Your Bearcat Propulsion System will give you a degree of reliability that
can only really be achieved through electromechanical controls. An added
advantage of relay control is that your local auto mechanic should have no
problem understanding how the system works. In principal it is largely an
oversized starter motor. This ease of maintenance gives you the option of
letting someone else maintain your electric for you. This is an important
feature of the bearcat system, especially if you don't have anyone in town
who feels comfortable working on complex transistorized control systems."
I guess that is one excuse for sticking to contactors, but I hope he uses
redundancy, since these are known to weld in the "on" position -- it's never
happened to me, but I don't race and my EVs only get to 350A max. Choosing
between 0V, 36V, or 72V, and using the tranny a lot seems a lot of work to
avoid 10# of electronics, esp. since most golf cart places can handle
Curtis' stuff.
--- End Message ---
--- Begin Message ---
From : Chris Zach <[EMAIL PROTECTED]> To : [EMAIL PROTECTED]
Subject : Re: EV1 vs Prizm... Date : Fri, 13 Jun 2003 20:27:40 -0400
Hm. So their "it cost us a billion to develop it" line really doesn't hold
water.
Actually, it does. Everything on the EV1 was designed from the ground up
for efficiency. The only items borrowed from other cars were the door
handles and the radio.
So GM designed the car, drive system, batteries and charging infrastructure
from scratch, for about $350 million total. This included new manufacturing
methods for the body and the first 100 cars built.
Even if it did cost a billion dollars, it would be money well spent. GM
spent about $1 billion to design the first Saturn, and that was a very
conventional car. Ford spent over $1 billion on its new Explorer redesign,
and that's YAT (Yet Another Trucklet.) There's nothing that could have
prevented the EV1 from succeeding if GM really wanted it to succeed.
Tim
_________________________________________________________________
Tired of spam? Get advanced junk mail protection with MSN 8.
http://join.msn.com/?page=features/junkmail
--- End Message ---
--- Begin Message ---
> Oops make that 69.1 amphours. I have a 50amp/50mv shunt which makes the
> readings on the eMeter 10x actual. 691 amp hours out of this
> little package
> would have been fine indeed! BTW this was down to the 9.6 volt shutoff
> recommended at this drain rate. 7.6 volts is the recommended
> cutoff for EV
> style amperages. My next discharge will be at 20 amps and I may
> go all the
> way up to a staggering 32 amps to get some idea of Peukert.
I'm interested in seeing what kind of real-world results you get. According
to Evercel's documentation, the NiZn batteries' capacity is fairly
unaffected by higher current draws, but I'm not banking on that.
Our truck has a current limiting pot on the controls, I have it dialed in to
~150A max currently; typical cruise draws about 40-60A. Note: This is per
string, actual amounts are doubled.
When these batteries go in, I'm planning a major rework of the truck's
systems, including a really nice per-battery data collection system. I like
to know exactly what's going on, and will be storing all the data in a Palm
Pilot with some custom software and (ideally) a wireless communication
system in the garage. Pull in and plug in, and it dumps the logged data to
my main office computer for analysis and automated warnings if it sees
anything out of the ordinary.
Also planning to put in some new seats! :-)
-Tom
Thomas Hudson
http://portdistrict5.org -- 5th District Aldermanic Website
http://portev.org -- Electric Vehicles, Solar Power & More
http://portgardenclub.org -- Port Washington Garden Club
http://portlightstation.org -- Light Station Restoration
--- End Message ---
--- Begin Message ---
Tim,
Thanks.. I was curious.. but couldn't recall the name.
-Frank
----- Original Message -----
From: Tim Clevenger <[EMAIL PROTECTED]>
Date: Monday, June 16, 2003 12:25 pm
Subject: Re: EV1 vs Prizm...
> >From : Chris Zach <[EMAIL PROTECTED]> To :
> [EMAIL PROTECTED]
> >Subject : Re: EV1 vs Prizm... Date : Fri, 13 Jun 2003
> 20:27:40 -0400
> >
> >Hm. So their "it cost us a billion to develop it" line really
> doesn't hold
> >water.
>
> Actually, it does. Everything on the EV1 was designed from the
> ground up
> for efficiency. The only items borrowed from other cars were the
> door
> handles and the radio.
>
> So GM designed the car, drive system, batteries and charging
> infrastructure
> from scratch, for about $350 million total. This included new
> manufacturing
> methods for the body and the first 100 cars built.
>
> Even if it did cost a billion dollars, it would be money well
> spent. GM
> spent about $1 billion to design the first Saturn, and that was a
> very
> conventional car. Ford spent over $1 billion on its new Explorer
> redesign,
> and that's YAT (Yet Another Trucklet.) There's nothing that could
> have
> prevented the EV1 from succeeding if GM really wanted it to succeed.
>
> Tim
>
> _________________________________________________________________
> Tired of spam? Get advanced junk mail protection with MSN 8.
> http://join.msn.com/?page=features/junkmail
>
>
--- End Message ---
--- Begin Message ---
Sorry,
Disregard this..
----- Original Message -----
From: FRANK GIANNANDREA <[EMAIL PROTECTED]>
Date: Monday, June 16, 2003 1:47 pm
Subject: Re: EV1 vs Prizm...
> Tim,
> Thanks.. I was curious.. but couldn't recall the name.
>
> -Frank
>
> ----- Original Message -----
> From: Tim Clevenger <[EMAIL PROTECTED]>
> Date: Monday, June 16, 2003 12:25 pm
> Subject: Re: EV1 vs Prizm...
>
> > >From : Chris Zach <[EMAIL PROTECTED]> To :
> > [EMAIL PROTECTED]
> > >Subject : Re: EV1 vs Prizm... Date : Fri, 13 Jun 2003
> > 20:27:40 -0400
> > >
> > >Hm. So their "it cost us a billion to develop it" line really
> > doesn't hold
> > >water.
> >
> > Actually, it does. Everything on the EV1 was designed from the
> > ground up
> > for efficiency. The only items borrowed from other cars were
> the
> > door
> > handles and the radio.
> >
> > So GM designed the car, drive system, batteries and charging
> > infrastructure
> > from scratch, for about $350 million total. This included new
> > manufacturing
> > methods for the body and the first 100 cars built.
> >
> > Even if it did cost a billion dollars, it would be money well
> > spent. GM
> > spent about $1 billion to design the first Saturn, and that was
> a
> > very
> > conventional car. Ford spent over $1 billion on its new
> Explorer
> > redesign,
> > and that's YAT (Yet Another Trucklet.) There's nothing that
> could
> > have
> > prevented the EV1 from succeeding if GM really wanted it to succeed.
> >
> > Tim
> >
> > _________________________________________________________________
> > Tired of spam? Get advanced junk mail protection with MSN 8.
> > http://join.msn.com/?page=features/junkmail
> >
> >
>
>
--- End Message ---
--- Begin Message ---
On Mon, 2003-06-16 at 08:38, Evan Tuer wrote:
>
> Peter VanDerWal wrote:
>
> > Let's say that you are driving around at low speed and only need about
> > 1kw from the motor. Depending on the RPM efficiency will be somewhere
> > around 80% +or- 5%. Motor is turning slow and voltage across it is low.
> >
> > Now let's use our CVT. Motor is spinning fast (that's the point of the
> > CVT right?) which means high voltage but low current. Believe it or not
> > this is where the LEMCO really sucks. Efficiency at high voltage/low
> > current can drop to 10% or less.
>
> Peter, I have to say that's a wee bit misleading. Any motor "sucks" when it's
> approaching no-load running, that's because you're applying current to overcome
> the losses and fan loading, and only getting a light breeze out.
No arguement here, my point was to avoid running motors at this point if
possible.
> Now, the LEMCO might be worse than a series wound motor *without* a fan in
> this respect, but that's not a fair comparison.
> The LEMCO double motor that's being talked about here is still above 80%
> efficiency with only 1KW mechanical load at 60V, running close to it's maximum
> speed. Not 10%.
The charts you list below are for the LEM-200 not the dual motor. These
are basically the same charts I was using.
The Dual motor is:
http://www.lemcoltd.com/pdf/120v_graph.pdf
or
http://www.lemcoltd.com/pdf/60v_graph.pdf
depending on if you want the 60V or 120V version.
Either way efficiency is WAY below 10% when producing 1kw.
> Produce the same power at a low RPM (say 400) and you will in fact end up
> with a much lower efficiency of about 50% as brush volt drop and I*R consume a
> greater proportion of the supply voltage. Not 80%.
> And, you'll probably need an external blower then as well..
Again, using the 12V charts for the LEM-200D and doubling the output
powwer, it shows about 84% when producing 0.5kw (I assumed 1kw from a
dual motor) and turning at 670 rpm. I assumed lowering the voltage a
bit (say 10V would produce about the same power at 400 rpm and
efficiency that was fairly close to this.
>
> Of course, you don't need to agree before you've looked at the curves:
> http://www.lemcoltd.com/pdf/Lemco200D_127.pdf
>
As I said you are looking at the wrong chart for the dual motor.
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Tom Hudson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, June 16, 2003 9:29 AM
Subject: RE: Evercel MB80 cycling
> > Oops make that 69.1 amphours. I have a 50amp/50mv shunt which makes the
> > readings on the eMeter 10x actual. 691 amp hours out of this
> > little package
> > would have been fine indeed! BTW this was down to the 9.6 volt shutoff
> > recommended at this drain rate. 7.6 volts is the recommended
> > cutoff for EV
> > style amperages. My next discharge will be at 20 amps and I may
> > go all the
> > way up to a staggering 32 amps to get some idea of Peukert.
>
> I'm interested in seeing what kind of real-world results you get.
According
> to Evercel's documentation, the NiZn batteries' capacity is fairly
> unaffected by higher current draws, but I'm not banking on that.
Ah, but you should. ;-) They aren't kidding.
The big issue with high current draws is that, especially in the early break
in phase, the battery heats up noticably.
S.
--- End Message ---
--- Begin Message ---
Message-ID: <[EMAIL PROTECTED]>
Date: Mon, 16 Jun 2003 16:46:16 -0700
From: Lee Hart <[EMAIL PROTECTED]>
MIME-Version: 1.0
To: [EMAIL PROTECTED]
Subject: Re: wheel motor
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Peter VanDerWal wrote:
> Oops, tired last night. I forgot to mention; CVTs approach 90% at 1:1
> when transferring MAX power. The losses in a CVT are due to friction,
> and friction remains nearly constant (at a given ratio) regardless
> of power. At lower power levels efficiency drops because the losses
> stay the same and now represent a larger portion of the input power.
>
> The numbers I posted last night were for a CVT operating near maximum
> power. Reality is that the CVT will normally be operating at power
> levels far from maximum and this is why the average efficiency from a
> CVT is around 50% or less.
This is the reason why most snowmobile belt type CVTs are rather
inefficient. However, there are ways around it.
Bob McKee used belt-type CVTs in some of his Sundancer EVs. To get
maximum efficiency at cruise, he had a 5:1 gear reduction in the wheel,
so the CVT could run at a 1:1 ratio at 60 mph. This gave him slightly
better than 90% overall drive efficiency from motor to wheel.
90% is a bit lower than gears, but the belt drive was lighter and
cheaper. Moreover, the CVT allowed the controller to be bypassed,
gaining a few percent there. Speed was varied with the CVT.
You said this type of CVT's losses are due to friction, and that
friction is constant. This is not quite true; while friction is roughly
constant, losses = friction x speed. You can change the ratio to slow
down the belt, and thereby reduce power loss. For example, you can run
the motor at half speed so CVT losses are halved, and yet still have the
same wheel speed. This can be desirable with PM motors.
--
Lee A. Hart Ring the bells that still can ring
814 8th Ave. N. Forget your perfect offering
Sartell, MN 56377 USA There is a crack in everything
leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
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