EV Digest 3861
Topics covered in this issue include:
1) Re: (FAQ?) DC vs. AC
by Victor Tikhonov <[EMAIL PROTECTED]>
2) Re: (FAQ?) DC vs. AC
by Victor Tikhonov <[EMAIL PROTECTED]>
3) Re: Curtis 1231C Heatsink
by "Patrick Maston" <[EMAIL PROTECTED]>
4) Re: (FAQ?) DC vs. AC
by David Dymaxion <[EMAIL PROTECTED]>
5) OEM Connectors, Relay sockets and Fuse holders
by "Don Cameron" <[EMAIL PROTECTED]>
6) Re: OEM Connectors, Relay sockets and Fuse holders
by Mark Farver <[EMAIL PROTECTED]>
7) RE: OEM Connectors, Relay sockets and Fuse holders
by "Roger Stockton" <[EMAIL PROTECTED]>
8) RE: OEM Connectors, Relay sockets and Fuse holders
by "Don Cameron" <[EMAIL PROTECTED]>
9) Re: Twike, pricey?, similar products
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
10) Re: Wet Rudman regs
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
11) Re: Wet Rudman regs
by John Lussmyer <[EMAIL PROTECTED]>
12) Re: Motor Trend, EVs in November Issue
by "Tom Shay" <[EMAIL PROTECTED]>
13) Re: (FAQ?) DC vs. AC
by "John Westlund" <[EMAIL PROTECTED]>
14) Re: Wet Rudman regs
by Gordon Niessen <[EMAIL PROTECTED]>
15) Re: OEM Connectors, Relay sockets and Fuse holders
by Seth Allen <[EMAIL PROTECTED]>
16) Re: (FAQ?) DC vs. AC
by "John Westlund" <[EMAIL PROTECTED]>
17) Re: (FAQ?) DC vs. AC
by Victor Tikhonov <[EMAIL PROTECTED]>
18) Alternative to Adapter
by "Bill Dennis" <[EMAIL PROTECTED]>
19) Re: Curtis 1231C Heatsink
by Lee Hart <[EMAIL PROTECTED]>
20) Re: Alternative to Adapter
by David Dymaxion <[EMAIL PROTECTED]>
21) Lightened Flywheel vs. Lightweight Flywheel?
by David Dymaxion <[EMAIL PROTECTED]>
22) RE: Alternative to Adapter
by "Bill Dennis" <[EMAIL PROTECTED]>
23) RE: Alternative to Adapter
by David Dymaxion <[EMAIL PROTECTED]>
24) li-ion boost pack musings - supercaps vs. lead acid?
by Gary Graunke <[EMAIL PROTECTED]>
25) [Fwd: li-ion boost pack musings - supercaps vs. lead acid?]
by Gary Graunke <[EMAIL PROTECTED]>
26) RE: [Fwd: li-ion boost pack musings - supercaps vs. lead acid?]
by "Bryan Avery" <[EMAIL PROTECTED]>
27) RE: Lightened Flywheel vs. Lightweight Flywheel?
by "Bryan Avery" <[EMAIL PROTECTED]>
--- Begin Message ---
Tommy Thorn wrote:
Hi Victor,
you have a great website - that's how I found this list in the first
place. However, you answer to #1 still left me with the "why"
question (ie., why recommend DC for drag racing). From this thread
it's become a bit clear, even if it seems there's no simple and
obvious reason (other than money and complexity).
DC systems are preferred for drag racing because starting torque of a DC
motor
is far higher than that of a similar power AC one, and the off-start
torque is critical
parameter for a drag racer. AC motors have broader range for constant torque
(area under torque curve), so given the time AC driven drag race car would
catch up with DC one, but the rule to count only 1/4 mile does not allow to
realize that advantage of an AC - it simply has no chance to get to the
optimal RPM (withoug gearing) before the end of the track.
But realize, this is only the cost issue - the fact is you can find any
power
motors, DC or AC - from not enough to too muchg size, so other systems
become your limitations (battery, transmission,etc).
Two weakest systems (other than battery) are the motor (brushes/commutator)
and transmission (gears/joints). You just pick what you'd enjoy breaking
first,
and let this be the weakest component - this may save the most expensive
one.
Victor
--- End Message ---
--- Begin Message ---
Tommy Thorn wrote:
BTW, a suggestion to make your excellent site even better: some kind
of date marked log would be good for a first time visitor.)
Thank,s point taken, I'll try to include dates next time I update the site.
I'd like to have/buy/build an EV, but it would have to have a
80-100mile range and capable of 80 mph (freeway commute). I imagine
converting something light, like an MR2 or a Catherham 7, with an AC
system running off Li Ion batteries. Is this even realistic?
Yes
And how much should I expect to spend?
Around $60k with $40-45k being the battery (today's prices), my guess.
Thanks,
Tommy
--- End Message ---
--- Begin Message ---
Lee, thanks for the explanation. I have a 1981 Jet Electrica that I am
redoing to get it back on the road. I have no idea what the current
draw will be. My plan is to mount the controller in the opening where
the radiator would be on a gas car, with the heatsink plate facing the
front and a muffin fan in front of the heatsink. I want to put the
heatsink and fan on first so I don't have to keep redoing the work. It
gets very hot here (Las Vegas area) in the summertime and I think the
controller will need all the cooling I can give it.
Patrick
<snip>
Lee Hart wrote:
Now, for your EV. The size of the heatsink should be chosen based on
a)
how much motor current you run, and b) how much airflow blows over the
heatsink.
The motor current tells you how much heat the controller is dumping
into
the heatsink. This is the average current, not the peak. A small,
light
EV like a Geo Metro or VW Rabbit only draws 50-100 amps average. A
heavy
EV like a pickup truck full of floodeds draws 100-150 amps. The more
heat produced, the bigger the heatsink needs to be to get rid of it.
The amount of airflow determines how good the heatsink will be at
getting rid of heat. If there is no fan, you need a *huge* heatsink to
get rid of the heat -- it needs to be larger than the controller
itself!
If you have a powerful fan blowing over the controller, no heatsink at
all is needed.
You can mount the heatsink out in the wind, such as where the car's
radiator went. This will provide a modest airflow when the car is
moving; but you'll find it is not adequate when driving in slow
traffic.
You'll need a fan, just as they do for a regular car's radiator.
As an example, my LeCar EV has a Curtis 1231C controller. Motor
current
is about 100 amps average. The controller is mounted to a flat
aluminum
plate, about 12" x 24" x 3/16". A plastic cover and the fender well
forms a tube over them, and a 4" muffin fan blows air through this
tube.
This has been entirely adequate to keep the controller from ever
getting
any more than about 140 degrees F.
Conversely, a friend had a Chevy S-10 pickup with a 1231C. Its motor
motor current averages more like 150 amps. It needed a finned heatsink
about 12" x 20" x 2", with two muffin fans blowing air across it.
--- End Message ---
--- Begin Message ---
http://www.vigillante.com might be able to do what you'd want on lead
acid batteries.
--- John Westlund <[EMAIL PROTECTED]> wrote:
> Given Greener Energy's Jester, with its 150+ mile range
> extra urban cycle and 70 MPH top speed, I'd guess that it is
> indeed possible for a $15-20k price tag.
>
> However, I'm willing to bet the Jester's acceleration with
> the Thunderskies was rather dismal.
>
> A Caterham 7? They look great, but have the aerodynamics of
> a brick(Cd*A > 8.0). If you're going to go the Caterham
> route, investiage the Lotus 11 replicas(Westfield, ect.).
> The original Lotus 11 had an overall Cd*A better than a
> Honda Insight. I remember investigating this car and finding
> it had a frontal area of 11.5 feet square and Cd of .40,
> although another source had the Cd listed at .36 with same
> frontal area(One may have been the regular and the more aro
> the LeMans). A properly constructed replica would be similar
> in aerodynamics, but you'd probably need some means to
> fabricate a top for it(Reducing drag even more!). Glider
> weight would be < 850 pounds. Not sure on structural
> rigidity, but with li ions, and keeping the car under 1,600
> pounds, you may not have too much to worry about. But
> investigate this. It looks like it would make a great
> long-ranger AND have performance. The original Lotus 11 S2
> LeMans only had 100 horsepower, did 0-60 in < 6 seconds,
> weighed about 970 pounds, and topped 140. With a 70
> horsepower(or higher) AC drive, you'd have more than
> adequate performance with a < 1,700 pound curb weight, with
> with perhaps excellent range. Only tradeoff is
> practicality.(BAH! Who needs that!?)
>
> MR2s are very aerodynamic for a production car. A 5.9-6.0
> overall Cd is about as good as you'll find, barring classic
> supercars like the Porsche Spyder or recent fuel misers like
> the Honda Insight, or perhaps an old CRX HF. Best of all, it
> is going to be a much more predictable chassis than most kit
> cars. But you'd need a lot more batteries for the range you
> want, than with a smaller car like a Westfield kit car or
> something like it. Performance? Thunderskies are awful I
> hear. To avoid the ultrap hassel, best just to use as light
> a car as possible. The MR2 is almost as light as it gets for
> a glider, barring the MG Midget, Austin Healey Bugey Sprite,
> Triumph Spitfire/GT6, Porsche 914, Datsun 1200, or Fiat 850,
> all of those whose aerodynamic characterisitcs are not as
> desirable as an MR2. However, picking a Spitfire over an MR2
> would shave at least 400 pounds off weight, and the Cd*A of
> aSpitfire is about 6.5.
>
>
> Of course, if money is too tight, you could do a lead acid
> EV with 50-60 miles range(@60 mph) for 1/2 the price.
>
>
> All matters what your goals/constraints are.
>
>
> >I'd like to have/buy/build an EV, but it would have
> >to have a 80-100mile
> >range and capable of 80 mph (freeway commute). I
> >imagine converting
> >something light, like an MR2 or a Catherham 7, with
> >an AC system running
> >off Li Ion batteries. Is this even realistic? And
> >how much should I
> >expect to spend?
>
>
=====
__________________________________
Do you Yahoo!?
Yahoo! Mail Address AutoComplete - You start. We finish.
http://promotions.yahoo.com/new_mail
--- End Message ---
--- Begin Message ---
I am searching, and searching for nice OEM style waterproof connectors (2-5
wire 10-16 gauge), relay sockets which I can easily bolt into a nice
electrical box, and OEM blade fuse holders. I have found **some** from
Bussman and Pico, but very limited selection. I have been all over the
internet without much luck. Any suggestions?
thanks
Don
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
--- End Message ---
--- Begin Message ---
Waytek wire has nearly everything you need to do a "professional" wiring
job. http://www.waytekwire.com They don't seem to mind small orders
either.
I have never found a definitive source for OEM connectors, but
Volkswagon connectors and pins are actually very reasonably priced thru
the dealer. (Or even cheaper through dieselgeek.com, amil order
Volkswagon parts outlet. Mention AustinEV and that you're buying for a
Beetle EV and he'll probably cut you a deal)
Mark
--- End Message ---
--- Begin Message ---
Don Cameron [mailto:[EMAIL PROTECTED] wrote:
> I am searching, and searching for nice OEM style waterproof
> connectors (2-5 wire 10-16 gauge),
Contact Randy at CEV <[EMAIL PROTECTED]>. He uses and sells the same
style connectors as used by GM, etc. I know he has 2, 4, and 6-wire
versions because I've bought a pile of them from him for my conversion.
;^>
> relay sockets which I can
> easily bolt into a nice electrical box,
This depends entirely on what relays you are using. If you can get your
hands on a Digikey catalog, you can see what sockets they offer for the
styles of relays they carry; the online catalog is a bit useless for
this.
> and OEM blade fuse holders.
Bear in mind that blade type fuses are only rated for 32VDC. Unless you
are adding fuses to the 12V system, you probably need to search up
holders for tubular 5x20mm or 0.25" x 1.25" fuses (at a minimum; since
you are planning an AC system, your pack voltage may push you into the
larger tubular fuses to get the voltage rating you need).
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Mark - thanks: waytekwire is a godsend... Just what I am looking for...
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Mark Farver
Sent: October 19, 2004 3:04 PM
To: [EMAIL PROTECTED]
Subject: Re: OEM Connectors, Relay sockets and Fuse holders
Waytek wire has nearly everything you need to do a "professional" wiring
job. http://www.waytekwire.com They don't seem to mind small orders
either.
I have never found a definitive source for OEM connectors, but Volkswagon
connectors and pins are actually very reasonably priced thru the dealer.
(Or even cheaper through dieselgeek.com, amil order Volkswagon parts outlet.
Mention AustinEV and that you're buying for a Beetle EV and he'll probably
cut you a deal)
Mark
--- End Message ---
--- Begin Message ---
I'm sorry. I think it's kind of silly to pedal a Twike. With two big guys
huffing and puffing we got up to maybe 15mph. I could see it as exercise or
getting home for sure albeit slow. Very slow. Lawrence Rhodes..........
----- Original Message -----
From: "Mark Hanson" <[EMAIL PROTECTED]>
To: "EVList (E-Mail)" <[EMAIL PROTECTED]>
Sent: Tuesday, October 19, 2004 5:19 AM
Subject: Re: Twike, pricey?, similar products
> The last time I looked at the Twike it was real pricey, around $18k. I was
> hoping for something like that for around $1k. Does anyone know of
> alternatives that can be peddled and maintain 55mph with electric assist
> that don't cost an arm & a leg? Thanks, Mark
>
> ----- Original Message -----
> From: "Schacherl Jens" <[EMAIL PROTECTED]>
> To: "EVList (E-Mail)" <[EMAIL PROTECTED]>
> Sent: Monday, October 18, 2004 5:24 AM
> Subject: Re: Twike (was Food energy)
>
>
> > ----- Original Message -----
> > From: "Christian Kocmick" <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Friday, October 15, 2004 5:37 PM
> > Subject: Re: OT: Food energy
> >
> >
> > >There was indeed someone in Seattle importing the Twike in about
> > >1998 named Victor Munoz. I think a few were sold in the Seattle
> > >and in the Portland areas. The European company (Swiss if my
> > >memory is correct) that was making them went bankrupt a few years ago.
> >
> > Fortunately, that's not the end of the story: the German importer (FINE
> Mobile GmbH) bought
> > the assets from the Swiss company and has continued production.
> > A new "PowerTwike" with NiMH batteries and 100+ miles range is in
> development and should be available next year (I've already seen, and even
> touched, the prototype ;-).
> > They also make a model called "Easy" without pedals.
> >
> > For details:
> > http://www.twike.com
> > http://www.twike.org
> > http://www.twikeklub.ch
> >
> > Regards, Jens
> >
>
--- End Message ---
--- Begin Message ---
I wouldn't dare charge with wet regs. I'll check tomorrow. I suspect they
will dry and I'll brush and vac them and hopefully they will be ok.
Lawernce Rhodes.....
----- Original Message -----
From: "Eric Johnson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, October 19, 2004 1:44 PM
Subject: RE: Wet Rudman regs
>
> Check them quickly. When my Mk2's got damp, they turned the
> FETs on half-way and caused much heat damage quite quickly.
> One burned through the board under the FET, requiring me to rebuild
> the circuit board with epoxy and ground fiberglas.
> But mine didn't turn on the green LEDs, as I recall. Maybe yours
> got water in a somewhat different location. Also, if you don't
> have loads, the FETs won't heat up. The heatsinking on the FETs
> (none on mine) will only handle the FETs full on or full off,
> not part way on acting as a resistor dissapating heat.
> I hope yours are behaving better than mine.
> And note that Rich sells replacement FETs at a very reasonable
> price.
> --
> Eric Johnson
> Portland, OR
> 1982 eDatsun PU
>
> >--- Original Message ---
> >Well the rains have come and my street parked damaged vehicle
> with the
> >packing tape and plastic cover gave out under heavy rain. It
> is tarped now
> >but all the little greens lights are lit up now on 19 regs causing
> a drain
> >on the pack and other hijinks as well I am sure. Can I just
> brush them off
> >with a paint brush and a vacuum. There is dust and water mixed
> just great
> >for extra paths. Crap. Lawrence Rhodes..........
>
>
>
--- End Message ---
--- Begin Message ---
At 04:19 PM 10/19/2004, you wrote:
I wouldn't dare charge with wet regs. I'll check tomorrow. I suspect they
will dry and I'll brush and vac them and hopefully they will be ok.
One of the problems is that the regs MAY turn on and discharge one or more
of your batteries. I had some of mine do that when they got wet.
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Ken Trough" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, October 19, 2004 4:00 AM
Subject: Re: Motor Trend, EVs in November Issue
Steve and Otmar or somebody else should post copies of their letters
to the editor in this forum. It seems like a shame to buy a magazine
just to read their letters.
Come on! You can afford to be involved with EVs and you can't afford a
measly magazine?!? Sorry, but I don't believe it.
Check your local library though. I'm sure they have a copy you can thumb
through for nothing.
I'll be buying a copy, just as I bought a copy of the last issue with
all the great EV related data. I believe we should support publications
that support us, and not look to simply post the data so that people can
avoid purchasing them.
I'm too stingy to spend money for something that can be had for nothing.
Today while my wife was getting a few items at a grocery store, I found
a copy of Motor Trend on the store's magazine rack and read Steve's and
Otmar's letters.
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--- Begin Message ---
>My requirements come from a ~ 33 mile freeway
>commute. I guess
>I could tighten the bounds a bit, but it would have
>to be usable
>for the daily commute to be worthwhile $20k+. That
>also implies a resonable
>acceleration.
>
>So, maybe I'm asking for too much.
You're not really asking for too much, at least it seems.
You just have to know where to compromise. you need to look
at what is 'reasonable' for you. Take my words with a grain
of salt, considering I have yet to build my own EV, although
I'm gathering cash, slowly but surely.
To give you an idea of cost, check out the following site on
Otmar's Porsche, which lists a breakdown of the cost of a
0-60 in 5 second, 140 MPH capable, 20-25 mile range at 60-65
MPH Porsche 914 EV:
http://evcl.com/914/
Specifically, click on 'conversion costs'.
Keep in mind his car weighs about 2,900 pounds, so if you
had something 2/3 the weight and a little more aerodynamic,
you may have what you're looking for for about 15k in parts.
Here's a list of the parts I have planned for my conversion,
which is calculated to be able to go up to 30-35 miles at 60
MPH to 80% DoD, 0-60 < 7 seconds, charge time from 0-100% <
2 hours, and top speed > 110 MPH:
-1x WarP 9'' series DC motor, $1,395, 160 lbs
-20x Exide Orbital ORB-DC-36 battery, $1,900, 820 lbs
-1x Godzilla Controller(72-300V DC, 1,000 amp max), $2,495,
23 lbs
-1x PFC 20 Charger, $1500, 15.5 lbs
-4x Vicor DC-DC converter, $400, 8 lbs
-Steel for battery racks, $100, 50 lbs
-Battery Cable, $100, 20 lbs
-x2 EV200AAANA contactors, $150, 5 lbs
-x2 Feraz Shawmut A50QS600-4 fuse, $220, 1 lb
-x1 Curtis Potbox, $75, < one ounce each
-x1 E-Meter, $235, 1 lb
-x1 Solid-State Ceramic Heater Core, $75, 1 lb
-Adaptor Plate...x1...$1000(I will be machining myself, so
don't count cost, 40 lbs
-Miscallaneous components(Heat shrink tubing, ect.), $800,
100 lbs
-Triumph TR6 Transmission + Rear Axel, $1000 from Ebay,
+40-50 pounds from original
-Leaf springs, $300
The glider weight of a Spitfire will be about 1,380 pounds,
and there is about 150 pounds I can remove from the interior
by using lighter seats, getting rid of a lot of the trip,
scraping out any sound deadener, ect.
All in all, a car with a sub 2,600 pound curb weight, and a
$15k conversion including partially restoring the car.
With a much more aerodynamic vehicle, you could get the
range to meet your commute. But you'll have to do
calculations. A conversion that would have, say, a 50 mile
range at 60 MPH to 80% DoD, and have 9kWh of usable energy
on board(About 28 Exide Orbitals), would need a Cd*A of <
5.0 and a curb weight of < 2,300 pounds. For 0-60 < 9
seconds, using a DC motor, you'd probably need about 600
amps on tap with that weight and 336V. With AC motor, you'd
probably need about 100 horsepower. But you'd also have to
keep in mind said battery pack is 1,150 pounds!
If you do go the Li Ion route, you are going to want a car
that weighs less than 1,700 if you want anything near
adequate performance without having to use ultracaps or a
hybrid pack. Contact those that have done electric Caterham
Sevens. There is a guy in Australia doing one with
Thunderskies. Get an idea of what performance he is
expecting, and see if this fits your needs. If it won't for
range, switch to a more aerodynamic but just as light
vehicle.
--- End Message ---
--- Begin Message ---
An air compressor does a good job and is much faster then brushing and
vacuuming. I have saved many a damp circuit that way. Canned air can also
be used. But leaving it to dry can lead to corrosion of the many
contacts. I have found it best to disconnect and blow each contact clean.
At 10/19/2004 06:19 PM, you wrote:
I wouldn't dare charge with wet regs. I'll check tomorrow. I suspect they
will dry and I'll brush and vac them and hopefully they will be ok.
Lawernce Rhodes.....
----- Original Message -----
From: "Eric Johnson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, October 19, 2004 1:44 PM
Subject: RE: Wet Rudman regs
>
> Check them quickly. When my Mk2's got damp, they turned the
> FETs on half-way and caused much heat damage quite quickly.
> One burned through the board under the FET, requiring me to rebuild
> the circuit board with epoxy and ground fiberglas.
> But mine didn't turn on the green LEDs, as I recall. Maybe yours
> got water in a somewhat different location. Also, if you don't
> have loads, the FETs won't heat up. The heatsinking on the FETs
> (none on mine) will only handle the FETs full on or full off,
> not part way on acting as a resistor dissapating heat.
> I hope yours are behaving better than mine.
> And note that Rich sells replacement FETs at a very reasonable
> price.
> --
> Eric Johnson
> Portland, OR
> 1982 eDatsun PU
>
> >--- Original Message ---
> >Well the rains have come and my street parked damaged vehicle
> with the
> >packing tape and plastic cover gave out under heavy rain. It
> is tarped now
> >but all the little greens lights are lit up now on 19 regs causing
> a drain
> >on the pack and other hijinks as well I am sure. Can I just
> brush them off
> >with a paint brush and a vacuum. There is dust and water mixed
> just great
> >for extra paths. Crap. Lawrence Rhodes..........
>
>
>
--- End Message ---
--- Begin Message ---
www.deutschipd.com
alsom molex JUST introduced a new sealed connector 12-22 AWG
Seth
On Oct 19, 2004, at 5:25 PM, Don Cameron wrote:
I am searching, and searching for nice OEM style waterproof connectors
(2-5
wire 10-16 gauge), relay sockets which I can easily bolt into a nice
electrical box, and OEM blade fuse holders. I have found **some** from
Bussman and Pico, but very limited selection. I have been all over the
internet without much luck. Any suggestions?
thanks
Don
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
--- End Message ---
--- Begin Message ---
>> And how much should I expect to spend?
>
>Around $60k with $40-45k being the battery (today's
>prices), my guess.
How much of that battery cost is management system, or is
that all battery?
--- End Message ---
--- Begin Message ---
John Westlund wrote:
And how much should I expect to spend?
Around $60k with $40-45k being the battery (today's
prices), my guess.
How much of that battery cost is management system, or is
that all battery?
I don't know exact prices; usually a BMS is about
20-40% of the cost of a battery it is serving.
Victor
--- End Message ---
--- Begin Message ---
Instead of using an adapter plate, what would be the feasibility of mounting
the motor and transmission separately, and running something like a
miniature drive shaft between them, with universal joints on each end?
Bill Dennis
--- End Message ---
--- Begin Message ---
Patrick Maston wrote:
> Lee, thanks for the explanation. I have a 1981 Jet Electrica that I am
> redoing to get it back on the road. I have no idea what the current
> draw will be. My plan is to mount the controller in the opening where
> the radiator would be on a gas car, with the heatsink plate facing the
> front and a muffin fan in front of the heatsink. I want to put the
> heatsink and fan on first so I don't have to keep redoing the work. It
> gets very hot here (Las Vegas area) in the summertime and I think the
> controller will need all the cooling I can give it.
Luckily, what is "hot" to you isn't all that hot for power electronics.
The Curtis 1231C delivers full power until its internal temperature
reaches 185 deg.F. At this point, it starts to "whine" audibly about the
high temperature (a 1.5 KHz whistle), and it cuts back the amount of
power available. If the internal temperature hits about 200 deg.F, it
shuts down completely.
The outside case temperature is typically 30-40 deg.F cooler than this.
Thus, you'll be ok until the case temperature hits about 145 deg.F.
Here's how you figure the size of the heatsink needed. Let's say the
highest air temperature you expect is 120 deg.F. 145 - 120 = 25 deg.F
temperature rise. The heatsink must have a temperature rise of 25 deg.F
or less.
Next, what is the motor current? The best way to know is to measure it,
but for now, let's say it draws 100 amps. The 1231C data sheet says it
has a voltage drop of 0.3v at 100 amps = 300 watts.
A 25 deg.F temperature rise is a 14 deg.C temperature rise. So, we need
a heatsink that is 14 deg.C / 300 watts = 0.05 deg.C/watt.
I pull out my trusty Wakefield heatsink catalog. It has a graph that
gives heatsink volume vs. thermal resistance in deg.C/watt. It says you
need:
- 8000 cu.in in still air
The Curtis 1231C case itself is 12" x 6.9" x 3.7" = 300 cu.in.
So this requires a 12" x 12" x 53.5" = 7700 cu.in heatsink!
Obviously, you do *not* want to do it this way!
- 900 cu.in in 1000 ft/min air (11 mph wind)
For example, a 12" x 24" x 2.1" heatsink in an 11 mph breeze.
This is realistically achievable. It's unlikely that you
will drive at less than 11 mph for any length of time, so
this size should work without a fan.
- 500 cu.in in 2000 ft/min air (22 mph wind)
That leaves 500 - 300 = 200 cu.in needed for the heatsink.
For example, the Curtis heatsink is 12" x 9" x 2" = 209 cu.in.
But 22 mph is a pretty stiff breeze; you'd need a couple fans
to maintain this kind of airflow.
--
"Never doubt that the work of a small group of thoughtful, committed
citizens can change the world. Indeed, it's the only thing that ever
has!" -- Margaret Mead
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
This would probably be most feasible for a Porsche 924/944 (one of
the few cars with motor in the front, and transaxle in the back, so
it does this already).
Something to consider is how are you going to react all the motor
torque? The tranny is designed to accept it, and is strongly mounted.
Bolting the motor to the tranny takes care of the motor torque, so
you need only support the motor weight. If you separate the two, the
motor must be very strongly mounted now, too. An unexpected side
effect can be twisting or bending the car body -- sometimes drag
racers run into this problem.
--- Bill Dennis <[EMAIL PROTECTED]> wrote:
> Instead of using an adapter plate, what would be the feasibility of
> mounting
> the motor and transmission separately, and running something like a
> miniature drive shaft between them, with universal joints on each
> end?
=====
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--- Begin Message ---
I was about to order a lightweight alumimum flywheel, when I saw you
can get "lightweight billet steel" flywheels that are about the same
weight. I also saw that a rear engined Porsche or VW that runs faster
than 11.99 in the 1/4 must have a billet flywheel -- wouldn't that be
a nice problem to have! I assume a steel billet flywheel is stronger,
so all things being equal I should get one of those rather than
aluminum?
I realized I don't know this answer and maybe could save myself some
$$: How much lighter can I have the stock flywheel machined? The
lightweight flywheels are expensive and about 40% lighter than stock.
How much can I have shaved off the stock flywheel? Thanks in advance.
=====
_______________________________
Do you Yahoo!?
Declare Yourself - Register online to vote today!
http://vote.yahoo.com
--- End Message ---
--- Begin Message ---
Thanks, David. This is kind of what Jeff at www.evproject.com had planned
for his 924, and what got me thinking about it. His idea involves attaching
the motor directly to the torque tube.
Bill Dennis
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of David Dymaxion
Sent: Tuesday, October 19, 2004 9:05 PM
To: [EMAIL PROTECTED]
Subject: Re: Alternative to Adapter
This would probably be most feasible for a Porsche 924/944 (one of
the few cars with motor in the front, and transaxle in the back, so
it does this already).
Something to consider is how are you going to react all the motor
torque? The tranny is designed to accept it, and is strongly mounted.
Bolting the motor to the tranny takes care of the motor torque, so
you need only support the motor weight. If you separate the two, the
motor must be very strongly mounted now, too. An unexpected side
effect can be twisting or bending the car body -- sometimes drag
racers run into this problem.
--- Bill Dennis <[EMAIL PROTECTED]> wrote:
> Instead of using an adapter plate, what would be the feasibility of
> mounting
> the motor and transmission separately, and running something like a
> miniature drive shaft between them, with universal joints on each
> end?
=====
__________________________________
Do you Yahoo!?
Take Yahoo! Mail with you! Get it on your mobile phone.
http://mobile.yahoo.com/maildemo
--- End Message ---
--- Begin Message ---
Bolting to the torque tube is a good idea.
--- Bill Dennis <[EMAIL PROTECTED]> wrote:
> Thanks, David. This is kind of what Jeff at www.evproject.com had
> planned
> for his 924, and what got me thinking about it. His idea involves
> attaching
> the motor directly to the torque tube.
>
> Bill Dennis
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
> Behalf Of David Dymaxion
> Sent: Tuesday, October 19, 2004 9:05 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Alternative to Adapter
>
> This would probably be most feasible for a Porsche 924/944 (one of
> the few cars with motor in the front, and transaxle in the back, so
> it does this already).
>
> Something to consider is how are you going to react all the motor
> torque? The tranny is designed to accept it, and is strongly
> mounted.
> Bolting the motor to the tranny takes care of the motor torque, so
> you need only support the motor weight. If you separate the two,
> the
> motor must be very strongly mounted now, too. An unexpected side
> effect can be twisting or bending the car body -- sometimes drag
> racers run into this problem.
>
> --- Bill Dennis <[EMAIL PROTECTED]> wrote:
> > Instead of using an adapter plate, what would be the feasibility
> of
> > mounting
> > the motor and transmission separately, and running something like
> a
> > miniature drive shaft between them, with universal joints on each
> > end?
>
>
> =====
>
>
>
>
> __________________________________
> Do you Yahoo!?
> Take Yahoo! Mail with you! Get it on your mobile phone.
> http://mobile.yahoo.com/maildemo
>
>
>
>
=====
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http://vote.yahoo.com
--- End Message ---
--- Begin Message ---
Bryan,
I ran an experiment with parallel strings of 90AH TS LiIon cells and
13AH Hawker Genesis batteries. The September 24 sets are best.
I did a 70A draw for 80 seconds (hill) in the first spreadsheet.
The second one was a 15 minute 25A draw.
The third one was a long sequence of draws and rests.
The voltage drop seems pretty linear to me--there are graphs in the
excel spreadsheets.
In the hill scenario, the pack was at 27.4 volts (obviously above two
fully charged Hawkers at 26 volts), and dropped to 23 upon drawing 70A.
The voltage slowly dropped to 22.65 volts during the 80+ seconds. They
popped back up to 26 quickly as the TS cells charged the Hawkers after
the draw was done.
Gary
From: "Bryan Avery" <[EMAIL PROTECTED]>
Date: Tue Oct 19, 2004 1:45 am
Subject: li-ion boost pack musings - supercaps vs. lead acid?
Hi guys,
I'm finally coming to terms with the fact that the 90Ah thunder-sky
li-ion batteries may not be enough to give me the acceleration I want all by
themselves, so I have been trying to run some numbers to get an idea of how
much improvement I could expect from adding a boost pack of either 1700F
supercapacitors (http://www.nesscap.com/prod/General/ESHSP-1700C0-002R7.PDF)
or 5Ah Hawker Cyclons
(http://www.enersysreservepower.com/cyc_b.asp?brandID=4).
I chose these size caps & batteries for comparison because both packs would
weigh about the same (~120 lbs.) and would conveniently fit perfectly into
the battery box under the rear seat of my car where the gas tank used to
reside. I'm still not sure if either of these is large enough to really
give the performance I am hoping for, but at least it's a place to start.
Using the equations on Victor's web page discussing his supercap project, I
have come to the conclusion that a pack of 148 1700F caps would result in a
65V voltage drop over a 10 second period @ 75A.
Is there any comparable mathematical equation I can use to figure the
voltage drop for the lead acid batteries? Is the voltage drop linear as
capacity decreases? At the moment, for the comparison, I am figuring 28
12V, 5Ah blocks for a total nominal voltage of 336V. So what's the best way
to draw a performance comparison between the lead acid and the supercaps?
-Bryan Avery
--- End Message ---
--- Begin Message ---
Oops--forgot to mention the data files are on my website at
ev.whitecape.org under hybrid pack experiments.
-------- Original Message --------
Subject: li-ion boost pack musings - supercaps vs. lead acid?
Date: Tue, 19 Oct 2004 21:50:46 -0700
From: Gary Graunke <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Bryan,
I ran an experiment with parallel strings of 90AH TS LiIon cells and
13AH Hawker Genesis batteries. The September 24 sets are best.
I did a 70A draw for 80 seconds (hill) in the first spreadsheet.
The second one was a 15 minute 25A draw.
The third one was a long sequence of draws and rests.
The voltage drop seems pretty linear to me--there are graphs in the
excel spreadsheets.
In the hill scenario, the pack was at 27.4 volts (obviously above two
fully charged Hawkers at 26 volts), and dropped to 23 upon drawing 70A.
The voltage slowly dropped to 22.65 volts during the 80+ seconds. They
popped back up to 26 quickly as the TS cells charged the Hawkers after
the draw was done.
Gary
From: "Bryan Avery" <[EMAIL PROTECTED]>
Date: Tue Oct 19, 2004 1:45 am
Subject: li-ion boost pack musings - supercaps vs. lead acid?
Hi guys,
I'm finally coming to terms with the fact that the 90Ah thunder-sky
li-ion batteries may not be enough to give me the acceleration I want all by
themselves, so I have been trying to run some numbers to get an idea of how
much improvement I could expect from adding a boost pack of either 1700F
supercapacitors (http://www.nesscap.com/prod/General/ESHSP-1700C0-002R7.PDF)
or 5Ah Hawker Cyclons
(http://www.enersysreservepower.com/cyc_b.asp?brandID=4).
I chose these size caps & batteries for comparison because both packs would
weigh about the same (~120 lbs.) and would conveniently fit perfectly into
the battery box under the rear seat of my car where the gas tank used to
reside. I'm still not sure if either of these is large enough to really
give the performance I am hoping for, but at least it's a place to start.
Using the equations on Victor's web page discussing his supercap project, I
have come to the conclusion that a pack of 148 1700F caps would result in a
65V voltage drop over a 10 second period @ 75A.
Is there any comparable mathematical equation I can use to figure the
voltage drop for the lead acid batteries? Is the voltage drop linear as
capacity decreases? At the moment, for the comparison, I am figuring 28
12V, 5Ah blocks for a total nominal voltage of 336V. So what's the best way
to draw a performance comparison between the lead acid and the supercaps?
-Bryan Avery
--- End Message ---
--- Begin Message ---
Thanks, Gary. That's some good info. More data in those files than my
brain can handle at the moment (It's been a long day). :-) That gives me a
place to start though.
-Bryan Avery
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Gary Graunke
> Sent: Tuesday, October 19, 2004 9:54 PM
> To: [EMAIL PROTECTED]
> Subject: [Fwd: li-ion boost pack musings - supercaps vs. lead acid?]
>
> Oops--forgot to mention the data files are on my website at
> ev.whitecape.org under hybrid pack experiments.
>
> -------- Original Message --------
> Subject: li-ion boost pack musings - supercaps vs. lead acid?
> Date: Tue, 19 Oct 2004 21:50:46 -0700
> From: Gary Graunke <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
>
> Bryan,
>
> I ran an experiment with parallel strings of 90AH TS LiIon cells and
> 13AH Hawker Genesis batteries. The September 24 sets are best.
> I did a 70A draw for 80 seconds (hill) in the first spreadsheet.
> The second one was a 15 minute 25A draw.
> The third one was a long sequence of draws and rests.
>
> The voltage drop seems pretty linear to me--there are graphs in the
> excel spreadsheets.
>
> In the hill scenario, the pack was at 27.4 volts (obviously above two
> fully charged Hawkers at 26 volts), and dropped to 23 upon drawing 70A.
> The voltage slowly dropped to 22.65 volts during the 80+ seconds. They
> popped back up to 26 quickly as the TS cells charged the Hawkers after
> the draw was done.
>
> Gary
>
>
> From: "Bryan Avery" <[EMAIL PROTECTED]>
> Date: Tue Oct 19, 2004 1:45 am
> Subject: li-ion boost pack musings - supercaps vs. lead acid?
>
> Hi guys,
>
> I'm finally coming to terms with the fact that the 90Ah thunder-sky
> li-ion batteries may not be enough to give me the acceleration I want all
> by
> themselves, so I have been trying to run some numbers to get an idea of
> how
> much improvement I could expect from adding a boost pack of either 1700F
> supercapacitors (http://www.nesscap.com/prod/General/ESHSP-1700C0-
> 002R7.PDF)
> or 5Ah Hawker Cyclons
> (http://www.enersysreservepower.com/cyc_b.asp?brandID=4).
>
>
>
> I chose these size caps & batteries for comparison because both packs
> would
> weigh about the same (~120 lbs.) and would conveniently fit perfectly into
> the battery box under the rear seat of my car where the gas tank used to
> reside. I'm still not sure if either of these is large enough to really
> give the performance I am hoping for, but at least it's a place to start.
>
>
>
> Using the equations on Victor's web page discussing his supercap project,
> I
> have come to the conclusion that a pack of 148 1700F caps would result in
> a
> 65V voltage drop over a 10 second period @ 75A.
>
>
>
> Is there any comparable mathematical equation I can use to figure the
> voltage drop for the lead acid batteries? Is the voltage drop linear as
> capacity decreases? At the moment, for the comparison, I am figuring 28
> 12V, 5Ah blocks for a total nominal voltage of 336V. So what's the best
> way
> to draw a performance comparison between the lead acid and the supercaps?
>
>
>
> -Bryan Avery
--- End Message ---
--- Begin Message ---
The aluminum flywheels (at least the one I got) are a two-piece arrangement
with the steel outer ring gear portion riveted onto the aluminum body of the
flywheel. I'm no expert, but I imagine this could have something to do with
the regulation, since I would think a solid one-piece flywheel would be less
likely to come apart at high speeds. Of course, the advantage of this sort
of arrangement in a conversion is that if you want even less weight it is a
simple matter to drill out the rivets and cut the steel ring gear off of the
flywheel as I did. No machining necessary.
-Bryan Avery
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of David Dymaxion
> Sent: Tuesday, October 19, 2004 9:17 PM
> To: [EMAIL PROTECTED]
> Subject: Lightened Flywheel vs. Lightweight Flywheel?
>
> I was about to order a lightweight alumimum flywheel, when I saw you
> can get "lightweight billet steel" flywheels that are about the same
> weight. I also saw that a rear engined Porsche or VW that runs faster
> than 11.99 in the 1/4 must have a billet flywheel -- wouldn't that be
> a nice problem to have! I assume a steel billet flywheel is stronger,
> so all things being equal I should get one of those rather than
> aluminum?
>
> I realized I don't know this answer and maybe could save myself some
> $$: How much lighter can I have the stock flywheel machined? The
> lightweight flywheels are expensive and about 40% lighter than stock.
> How much can I have shaved off the stock flywheel? Thanks in advance.
>
>
> =====
>
>
>
>
> _______________________________
> Do you Yahoo!?
> Declare Yourself - Register online to vote today!
> http://vote.yahoo.com
--- End Message ---
