EV Digest 2849
Topics covered in this issue include:
1) conditioning rig
by Fred Whitridge <[EMAIL PROTECTED]>
2) Need US 2200's
by [EMAIL PROTECTED]
3) Phoenix in 96' was the turning point
by "Mark Hanson" <[EMAIL PROTECTED]>
4) Re: DC to AC
by "Mark Hanson" <[EMAIL PROTECTED]>
5) RE: Starting torque
by "Chris Tromley" <[EMAIL PROTECTED]>
6) RE: Need US 2200's
by "Chris Tromley" <[EMAIL PROTECTED]>
7) Evercel Nickel-Zinc
by "Tom Hudson" <[EMAIL PROTECTED]>
8) Nedra Icalendar schedule
by "Eric Penne" <[EMAIL PROTECTED]>
9) Re: 2 Speed Motorcycle Transmission
by "Mark Thomasson" <[EMAIL PROTECTED]>
10) UPS batteries
by "damon henry" <[EMAIL PROTECTED]>
11) Re: UPS batteries
by Bruce EVangel Parmenter <[EMAIL PROTECTED]>
12) Re: Starting torque
by "Mark Thomasson" <[EMAIL PROTECTED]>
13) Re: conditioning rig
by Lee Hart <[EMAIL PROTECTED]>
14) Re: Need US 2200's
by Lee Hart <[EMAIL PROTECTED]>
15) Another MagneCharger
by "Christopher Zach" <[EMAIL PROTECTED]>
16) OT Question: Lots of Small Metal Enclosures
by "Eric Penne" <[EMAIL PROTECTED]>
17) Re: OT Question: Lots of Small Metal Enclosures
by seth <[EMAIL PROTECTED]>
18) Re: Lowest frequency (was Re: AC vs DC)
by Victor Tikhonov <[EMAIL PROTECTED]>
19) Re: Evercel Nickel-Zinc
by Victor Tikhonov <[EMAIL PROTECTED]>
20) Crimp connectors
by John Lussmyer <[EMAIL PROTECTED]>
21) Re: Starting torque
by Rich Rudman <[EMAIL PROTECTED]>
22) Re: Evercel Nickel-Zinc
by Rich Rudman <[EMAIL PROTECTED]>
23) Re: Lowest frequency (was Re: AC vs DC)
by Rich Rudman <[EMAIL PROTECTED]>
24) Re: Starting torque
by Victor Tikhonov <[EMAIL PROTECTED]>
25) Re: Lowest frequency (was Re: AC vs DC)
by Victor Tikhonov <[EMAIL PROTECTED]>
26) Re: 2 speed transmission for racing?
by [EMAIL PROTECTED]
27) Re: Lowest frequency (was Re: AC vs DC)
by Paul G <[EMAIL PROTECTED]>
28) RE: OT Question: Lots of Small Metal Enclosures
by "Harris, Lawrence" <[EMAIL PROTECTED]>
29) RE: 1958 Chevy Truck Conversion
by "Michael Hills" <[EMAIL PROTECTED]>
--- Begin Message ---
Roger Stockton steered me to two Sorensen 20 volt 30 amp programmable
supplies on eBay and I won my first auction at a tad less than $300 for
the pair or about 12 cents on the as new dollar. they look brandy
spandy new and both work. One is having a "Lee Hart Optima Lazarus
Raise 'em From the Dead" session yawining away putting 1/2 amp into a YT
that was long since removed from the car. Which leads me to the first
question: How long to put 1/2 amp into the batt before giving up? Its
been 3 days now and voltage has only wandered up to 11.7. I am
heartened that the "Amps" light has come on meaning that I am not
amperage limited. I've set the OVP for 15volts and dialed in a max
voltage of 14.7. This tired soldier doesn't want to take more than 3
amps at the moment. When do you fill out the YT death certificate and
hang your head in shame as a serial battery murderer?
The LiOn threads have me understanding how little of the technical
battery jargon and theory I have mastered. How does one derive the
internal resistance of a battery? I've looked at Chris Brune's
Thundersky charts with interest and envy. (Well envy as to presentation
if qualminess at the data content). Also at the data Lee has posted on
his Thundersky's.
I plan to build at least one and maybe two conditioning rigs with the
Sorensens. I'll use a spare eMeter and have purchased another Java TINI
to control the thing, monitor the temps, and log data. 100 watt 12v
bulbs with regular screw in bases seem to be in short supply at my usual
neighborhood haunts but I have ordered some. In the mean time I have
three VW Cabrio headlights wired up which draw a measly 8.9 amps (but
light up the workbench nicely...). I have 22 MB80's sitting in the
garage awaiting such a rig. Hopefully this weekend I'll make great
strides at getting my 1/2" copper pipe cooling rig and the first string
in the car.
--- End Message ---
--- Begin Message ---
Hi all,
I'm in the process of rebuilding the rear bat box in my Henney. Once that is
done (today or tomorrow I Hope) I can replace all the batteries.
I have had NO luck in finding batteries locally for what seems to be a fair
price. Most of the Golf Cart shops around here only stock Trojans, (which are
not quite the right size). I did FINALLY find a shop that carries us-batteries,
but they want $65.00 each plus tax.
That sounds high to me as I seem to recall people on list saying that they are
getting those, or batteries like those, for about $50.00 each.
I tried calling US battery directly, but they just give me the name of a "local
distributer" who doesn't seem to want to return my calls.
So, anyone know what I have to do to get 12 US battery 2200's at a good price (I
am told that Interstate U-2200 batts are the same battery, just re-branded, so
that will work as well).
Thanks,
James
--- End Message ---
--- Begin Message ---
I was there and it was quite a show, got really excited and I don't get
excited that much :-). Always liked DC, simple & cheap(er). Recently
however, the Phoenix races have appeared to peeter out as other areas have
come on board. Hope to see a good race in Hagerstown Md at the Mason-Dixon
speedway Sunday June 29th!
> Roderick Wilde wrote:
> >
> > I concur with Rich on this subject. I believe Rich still remembers that
run
> > in Phoenix in 1996 when we put the Mazda up against a specially prepared
EV1
> > that had done 183 MPH. The GM dudes had just changed the gearing for
drag
...snip...
--- End Message ---
--- Begin Message ---
I just tried a class-D amp hip4080a switching lower at 100kHz instead of the
200kHz typical with a wider dead time of 1usec instead of 200ns and fed it
with a 60hertz sine generated with a MC68HC908QY4 microcontroller (sine
lookup table & RC on output 2k&10uf). Works ok at 300W but will take more
effort at higher power, probably twin H-bridge fets like TriPath does for
their subwoofers.
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, June 11, 2003 1:37 PM
Subject: Re: DC to AC
> Lee Hart wrote:
> >
>
> > The simple answer is that perfect sinewaves aren't needed, and that even
> > crude 6-step waveforms give you 90% or more of a motor's sinewave
> > performance and efficiency.
> > --
>
> That was my point on the E-cycle controller thread.
> That last %10 can really be hard to get.
>
>
> Rich Rudman
> Manzanita Micro
> www.manzanitamicro.com
> 1-360-297-7383,Cell 1-360-620-6266
>
--- End Message ---
--- Begin Message ---
Mark Thomasson wrote:
> If anyone knows where I can get a small two speed
> transmission let me know. It would solve a lot of problems in
> my EV motorcycle design.
I'm not a Harley guy, but doesn't the Sportster have a separate gearbox
(and a rather compact one at that)? The fact that it's a four(?) speed
doesn't matter much. You can use the gears you want. If you need
maximum efficiency you could grind the teeth off the gears you don't
need, or replace them with spacers.
<snip>
> Some EV motorcycles shown on the internet have gear
> boxes that were chopped off motorcycle engines, but this
> method looks like more machine work than I am capable of.
There isn't really much machine work to remove it if there are existing
holes you can use for mounting the newly-liberated gearbox. It most
involves cutting and smoothing the aluminum casting away from the
gearbox. The real problem is that if the gearbox was integral with the
engine it probably shared the engine's oil. You have to make inlet and
drain fittings and seal the input shaft. The only modern bikes I know
that use a dry clutch and/or separate trans (so all that extra machine
work is unnecessary) are some of the later (and pricey) Ducatis, the
older BMWs and Moto Guzzis. My involvement with motorcycles ended long
ago, so there may be others.
I personally think an e-bike based on a /5 or /6 BMW has tremendous
potential. It's extremely light for its size, comfort and GVWR. The
frame is simple and open, with lots of room for batteries. You can keep
the trans and mount your motor much like a car. There are plenty of
aftermarket goodies available to turn it into anything from a road racer
to a cross-country touring bike.
> Some older Triumphs and HD's may have had gear boxes already
> separate from the engine, but these are hard to find without
> buying the whole bike.
Those gearboxes weren't very strong, either. The materials were iffy
and some had poor designs. Not worth the effort.
<snip>
Chris
--- End Message ---
--- Begin Message ---
James Jarrett wrote:
> I'm in the process of rebuilding the rear bat box in my
> Henney. Once that is done (today or tomorrow I Hope) I can
> replace all the batteries.
>
> I have had NO luck in finding batteries locally for what
> seems to be a fair price. Most of the Golf Cart shops around
> here only stock Trojans, (which are not quite the right
> size). I did FINALLY find a shop that carries us-batteries,
> but they want $65.00 each plus tax.
>
> That sounds high to me as I seem to recall people on list
> saying that they are getting those, or batteries like those,
> for about $50.00 each.
>
> I tried calling US battery directly, but they just give me
> the name of a "local distributer" who doesn't seem to want to
> return my calls.
Hi James,
I just placed an order for 20 US 145s coming direct from US Battery.
The price was very good and they are shipping to my door (near
Philadelphia) from Georgia. They don't pick up cores, but you can
handle that locally pretty easily.
I hesitate to give you contact information directly. My impression is
that US Battery sells direct to EVers as a courtesy (a very welcome
one!) and I'd rather leave it to them to manage. Contact Nawaz Qureshi
at [EMAIL PROTECTED] for details. Nawaz, what's the company
position on this? Is it a standing offer to EVers everywhere, or do you
handle it on a case-by-case basis?
It bears repeating here that US Battery has been very supportive of EVs.
Nawaz has helped us all on the EVDL with his technical advice. He's
helped me and probably hundreds of others with off-list questions. My
contact at US Battery in Georgia has been very gracious. All that and a
great product as well!
Chris
--- End Message ---
--- Begin Message ---
Would anyone with experience using Evercel's Nickel-Zinc batteries please
contact me off-list (heck, even on-list would be OK, as long as nobody
objects).
The lead-acid batteries in our Solectria E-10 pickup are degrading (my wife
hit reduced-power mode at 32Ah yesterday) and I want to get the ball rolling
to replace them ASAP. Evercel's MB80-12-8 nickel-zinc batteries are a
perfect replacement for the group 24 batteries that are in the truck now,
and I'm willing to take the plunge.
I'd like to talk to someone who has used these batteries so that I can get a
better handle on what will be involved with the upgrade on our truck
(cooling, Brusa charger profile, etc.).
Even though the Nickel-zincs have much more capacity than the lead-acids,
we're going to stick with two strings so that current draws are reduced
during driving. The only concern I have about this is that the charging
procedure specified in the Evercel website shows a constant 22A, and our
charger isn't going to be able to put out more than about 20A, with each
string seeing 10A. From what I've read in the detailed PDF on Evercel's
website, this probably isn't a problem (may be better for the batteries).
It should just mean a longer charge.
I've asked Evercel for quotes, availability and lead times but so far
haven't gotten a response (not encouraging).
Anyway, if someone with experience in these batteries could contact me, I'd
like to pick your brain a bit so I can get my truck upgraded. Thanks!
-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 ---
For those you using a newer personal information manager that supports the
Ical format, I've posted an ical file for the next 2 nedra races.
Mozilla, newer Outlook, and newer Palms work with Ical. Macs support Ical
very well.
The next 2 races listed on the nedra website are Power of DC and Nedra
Nationals.
http://www.olug.org/~epenne/nedra.ics
The best part is that it is just text. You may need to right click on the
link and choose "Save As..." to download it. Mozilla Calendar will allow
you to "subscribe" to it and then update occasionally from the web by just
putting in that web address.
Later
Eric
--- End Message ---
--- Begin Message ---
$300 would be my limit for a 2 speed transmission capable of transferring
15 hp. Probably will not find something this cheap unless it's already
being mass produced for another application.
----- Original Message -----
From: "Gordon Niessen" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, June 11, 2003 9:22 PM
Subject: 2 Speed Motorcycle Transmission
> I think a lot of us would love to have a small 2 spd tranny. The problem
> is that even if half of use doing motorcycle conversions wanted one it
> would not be much of a market. Of course if it worked for go-karts and
> ATVs it might help.
>
> Quick poll: How much would you pay for one? $250, $500, $750, more?
>
--- End Message ---
--- Begin Message ---
I loaded my motorcycle up in my van and brought it into work the other day
as I was planning on stopping by the salvage yard on my way home to show it
to the folks there who have taken an interest. I did lots of show and tell
while at work. I made sure to include the facilities guys who loved it and
then mentioned to them that when I start riding it to work I would need a
place to plug in. They assured me this would not be a problem and even
suggested bringing it inside and parking it right next to the forklift.
They also pointed me to a UPS battery that they had lying around and told me
that they had six more in the warehouse I was welcome to. They are brand
new, but have been sitting in there cardboard boxes unopened for about two
years. I took them all home yesterday.
After opening them I found out that they are Power Battery PRC-1265. They
are rated at 65ah and are VRLA AGM batteries. They weigh in at 50 pounds a
piece. I found a constant power discharge to 1.67V per cell table provide
by the manufacturer. At 119 amps they claim they will last 30 minutes.
This would be a cruising speed of about 45mph for me, so it would seem that
4 of these would give me a maximum range of 15-20 miles. This is not enough
to get me to work, but is much better then the 5-6 miles I currently have
with my test pack. They also seem like they will go on my bike fairly
easily, especially since they can be oriented in any direction. The only
piece of info that I could not seem to chase down was how deeply they like
to be cycled. I know they are designed to maximize lifespan on a float
charge, but they also seemed to be designed to put out decent amps when
needed. Does anyone have experience using these type of batteries. Since
they were free, a short lifespan doesn't really matter that much to me, and
I am still looking for my final battery solution. I would like to get my
NiCads on the bike if I can get the tol fit someplace. Having these other
batteries would give me lots of time to have some cool NiCad battery boxes
fabricated.
I have thought through all sorts of possible scenarios. One that is
especially intriguing to me is using the Nicads to setup a dump charge
station or two along my route. All I would need is some EV friendly
business or individual along the way. In this case, the UPS batteries might
be a final solution, that is if they can take fast charges.
I put one of the batteries on the charger when I got home and it seemed to
take a charge just fine. I started to do a load test on it, but the only
load I had was my motorcycle. It draws a pretty steady 40 amps at 12V. It
was getting late though, and my neighbors windows are usually open, and the
chain was making quite a bit of noise relative to the silence of the
cul-de-sac, so I discontinued after only a couple of minutes. Maybe I will
have to swing by John Wayland's house and see if I can borrow one of his
aircraft landing lights.
damon
_________________________________________________________________
Tired of spam? Get advanced junk mail protection with MSN 8.
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--- End Message ---
--- Begin Message ---
The problem with UPS batteries for EV use, is they
are not designed for the vibration mounting in a vehicle
will cause, and they are not designed for regular
deep discharge like traction batteries.
50 lb UPS battery seems small to the huge one cell (2V)
batteries in the UPS rooms that supported the computer
rooms I installed in.
=====
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor & RE newswires
. (originator of the above ASCII art)
=====
__________________________________
Do you Yahoo!?
Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
http://calendar.yahoo.com
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Peter VanDerWal" <[EMAIL PROTECTED]>
To: "EV" <[EMAIL PROTECTED]>
Sent: Wednesday, June 11, 2003 11:17 PM
Subject: Re: Starting torque
> > If anyone knows where I can get a small two speed transmission let me
know.
>
> Hmm, how about a simple automatic transmission? Uses chain drive. Low
> gear uses a sprocket with a one-way overrunning clutch, high gear uses a
> Centrifugal Clutch like a go-kart uses.
>
> Starts out with low gear engaged and when motor RPMs hit about 2k the
> centrifugal clutch starts to kick in and overruns low gear.
>
> Cheap overrunning sprokets are available at your local bike store. They
> use them on BMX style bikes, they are designed to fit something like a
> 1" keyed shaft.
>
>
This is an interesting idea. Let me know if what I describe below is the
concept you are suggesting:.
Several configurations come to mind.
1. Get a motor with a long enough shaft to mount both the one-way clutch
(OC) and the centrifugal clutch (CC) and run two rear sprockets on the same
side of the rear wheel.
2. Get a double shafted motor and mount the OC and the CC on different side
of the motor. Run two rear sprockets, one on each side of the rear wheel.
3. Use a jackshaft between the motor and the rear sprocket, so you only
need one sprocket on the rear wheel and all the extra sprockets are on the
jackshaft and the motor..
4. I wonder if the OC and CC could be mounted on the jackshaft? Would the
CC work backwards, driving the drum side with the motor and outputting power
to the piece that is keyed to the jackshaft?
5. ???
Problems:
1. I will not be able to use the low gear through the full range of motor
speed. For example, I might want to stay in low gear at full throttle going
up a hill.
2. Would BMX bicycle chain be strong enough for the torque from a 15 HP
drive motor?
3. Would this even work? If I accelerate to 2000 RPM and the clutch locks
up, the motor will immediately slow down to match rear wheel speed at the
new gear ratio. Then the clutch unlocks and the motor speeds up again,
etc....... Do I need a large deadband in the clutch to make this work? Or
maybe the centrifugal part should be on the output side of the clutch, so
the clutch picks up based on wheel speed rather than motor speed?
Maybe someone on the list with more mechanical savvy than me can shed some
light on this?
Thanks, Mark T.
--- End Message ---
--- Begin Message ---
Fred Whitridge wrote:
> having a "Lee Hart Optima Lazarus Raise 'em From the Dead" session
> yawning away putting 1/2 amp into a YT that was long since removed
> from the car. Which leads me to the first question: How long to
> put 1/2 amp into the batt before giving up? Its been 3 days now
> and voltage has only wandered up to 11.7v.
If you have a battery that is OK but *very* dead (10-12v open-circuit),
then it won't draw any current when you connect it to a charger. The
voltage will immediately shoot up past 14v at very low current. Here
what is happening. The electrolyte in a dead lead-acid cell is almost
pure water; all the sulfuric acid is tied up in lead sulfate. Water is
such a poor conductor that no current can flow. No current means no
charging. So it *stays* dead.
To fix it, you apply an unlimited voltage but limit the current to
something like 1% of the cell's amphour rating. For an Optima this means
about 0.6 amps. Let the voltage go as high as it wants; it can easily
exceed 15v for a 12v battery, and I have seen really dead ones go to
20-25v!
Watch the current. It will be very low, and the voltage will go right up
to your charging supply's voltage limit. But, the current will
s-l-o-w-l-y increase, over a period that may take many DAYS. Every
amphour you put in puts more acid back into the electrolyte, lowering
its resistance, and allowing more current.
Eventually (if the battery is good), the current will hit whatever
current limit you have allowed, and the voltage will fall to 12.xxx
(normal for a dead battery). At this point, you can disconnect your
special high-voltage current-limited charger, and connect a normal
charger. The battery should continue charging normally. It will have low
amphour capacity after its near-death experience, but capacity will
gradually improve over the next dozen or so charge-discharge cycles.
> I've set the OVP for 15volts and dialed in a max voltage of 14.7.
> This tired soldier doesn't want to take more than 3 amps at the
> moment. When do you fill out the YT death certificate and hang
> your head in shame as a serial battery murderer?
This indicates that it isn't just dead; something DIFFERENT is wrong.
One possibility is that it has lost water. Check the seal around the
edge by trying to lift it; see if it is loose. You can also try weighing
the battery, and seeing if it has lost weight from leaking or gassing.
if it has, you can add water to an Optima by drilling holes in the cover
so as to miss the internal connections, add water, and plug the holes
with a stainless steel screw.
Another possibility is that it has been chronically overcharged. This
can cause positive grid corrosion, resulting in a battery with much
higher internal resistance. It can deliver plenty of amphours at light
load, but the voltage sags below 10.5v almost immediately with any
heavier load. It also charges only at abnormally low current. I know of
no cure for this but a new battery.
> How does one derive the internal resistance of a battery?
You measure its voltage at two different loads. For example,
12.5 volts at 1 amp
12.2 volts at 25 amps
Now calculate internal resistance as R = (change in V) / (change in A):
R = (12.5v - 12.2v) / (25a - 1a)
R = 0.3v / 24a
R = 0.0125 ohms or 12.5 milliohms
A good Optima is supposed to be around 3 milliohms when fully charged.
--
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
--- End Message ---
--- Begin Message ---
[EMAIL PROTECTED] wrote:
> I have had NO luck in finding batteries locally for what seems to
> be a fair price. Most of the Golf Cart shops around here only stock
> Trojans, (which are not quite the right size). I did FINALLY find
> a shop that carries US batteries, but they want $65.00 each plus
> tax.
Golf cart batteries are a "standard" size, so any of them should fit.
But of course, the standard is loosely adhered to by the manufacturers,
and vehicle designers often assume the dimensions of whatever they
happen to have on hand. I've had to trim off little bumps on the cases
on more than one occasion to squeeze them in.
You can usually "haggle" to get a better price when you're buying a
quantity of batteries.
Contact Nawaz Quershi, an Electrochemist at US Battery, (909) 371-8090,
email <[EMAIL PROTECTED]>. He may be able to help you find a
sympathetic dealer, or even have them shipped direct.
Or, you can just go to Sam's Club; their 6v golf cart batteries are
about $40 each at my local store. Though not quite as good at USB or
Trojans, they will work just fine as a "trainer" pack.
--
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
--- End Message ---
--- Begin Message ---
I just got another MagneCharger. YAAY!!!!
Now I can install this one at my parent's house in Timonium MD and have a
place to flash charge. With a range now of 50 miles and a 80% charge time of
2 hours I can go a *lot* more places with my Prizm!
Now to put one in Silver Spring MD somewhere :-)
Chris
--- End Message ---
--- Begin Message ---
I have the need for 100-200 small metal enclosures approx. in a 9" cube.
Seeing as how this is a list of people that know lots of little resources,
I was hoping somebody would have a source for something like this.
The enclosure is for a single board computer which is a PC with everything
integrated used for embedded projects mostly.
Thanks
Eric Penne
[EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
www.parvus.com makes nice PC/104 and EBX enclosures from basic to NEMA
4X or more. I liked their stuff the last time I used it.
Seth
Eric Penne wrote:
>
> I have the need for 100-200 small metal enclosures approx. in a 9" cube.
> Seeing as how this is a list of people that know lots of little resources,
> I was hoping somebody would have a source for something like this.
>
> The enclosure is for a single board computer which is a PC with everything
> integrated used for embedded projects mostly.
>
> Thanks
> Eric Penne
> [EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
>
> Victor Tikhonov wrote:
> > say your lowest freq is 1 Hz or 1 rev of the shaft per second.
> > At stall, the field must rotate 1 rev/sec to still have slip (so
> > [it produces] torque). If your vehicle rolls back such that the
> > shaft rotates backwards exactly 1 rev/sec, this means the output
> > freq must be 0 Hz to have the same relative slip and torque; i.e.
> > a phase gets continuous pwm (unchangeable).
>
> Yes, that is correct. Here is the problem: Under these conditions you
> have DC flowing in the motor windings.
It's not DC, it's PWM pulses. Even though they're in one direction
(DC in that sense), the most powered phase gets continuously less than
100% duty, perhaps at stall even less than 30%, so it won't overheat.
(besides inverter's protection from overheating, different issue).
At high power demands total current through the same winding integrated
over few seconds is higher than stall current through the same phase.
I can roll backwards with shaft speed -1 RPM all day long, the
inverter (just one phase's IGBT's really) will be cooler than at
high speed.
The question was - to have smooth transition from neg to pos
freq it must be able to generate <1Hz freq, infinitely close to 0.
Yet the spec says 0.7 Hz min. Any clues?
Victor
--- End Message ---
--- Begin Message ---
I have no first hand experience with NiZn, but manufacturer recommended
as low as 8A or 11A charging currents for MB80. So, yes, it will take
longer, but shouldn't harm anything. Overnight charging is plenty of
time anyway, IMHO no reason to rush in tens of amps (unless you don't
charge at home daily and take advantage of short opportunity chargings).
Victor
Tom Hudson wrote:
>
> Would anyone with experience using Evercel's Nickel-Zinc batteries please
> contact me off-list (heck, even on-list would be OK, as long as nobody
> objects).
>
> The lead-acid batteries in our Solectria E-10 pickup are degrading (my wife
> hit reduced-power mode at 32Ah yesterday) and I want to get the ball rolling
> to replace them ASAP. Evercel's MB80-12-8 nickel-zinc batteries are a
> perfect replacement for the group 24 batteries that are in the truck now,
> and I'm willing to take the plunge.
>
> I'd like to talk to someone who has used these batteries so that I can get a
> better handle on what will be involved with the upgrade on our truck
> (cooling, Brusa charger profile, etc.).
>
> Even though the Nickel-zincs have much more capacity than the lead-acids,
> we're going to stick with two strings so that current draws are reduced
> during driving. The only concern I have about this is that the charging
> procedure specified in the Evercel website shows a constant 22A, and our
> charger isn't going to be able to put out more than about 20A, with each
> string seeing 10A. From what I've read in the detailed PDF on Evercel's
> website, this probably isn't a problem (may be better for the batteries).
> It should just mean a longer charge.
>
> I've asked Evercel for quotes, availability and lead times but so far
> haven't gotten a response (not encouraging).
>
> Anyway, if someone with experience in these batteries could contact me, I'd
> like to pick your brain a bit so I can get my truck upgraded. Thanks!
>
> -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
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--- Begin Message ---
I asked a couple days ago about which connectors to use, and a couple
people told me that I'll probably need some ring crimp connectors in the
4,6, or 8 ga size.
WHERE can I find things in these sizes? (Remember, I don't live near a
city, so nobody near me carries them.)
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream....
http://www.CasaDelGato.Com
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--- Begin Message ---
Lee Hart wrote:
>
> Seth wrote:
> > I think it has something to do with needing three 2000amp half
> > bridges instead of one, for starters.
>
> Exactly so.
A couple of points.
The torque of a Synchronous AC motor or BLDC motor is linear to the
Amps. The coils are pushing against magnets of a known strength. More
amps more torque. No surprise.
Series Wound DC is amps squared, or the Armature amps are pushing
against the same field amps. This holds until the steel staurates. Or
the copper melts, or the brushes vaporize.
Nice effect, the motor it self down shifts as the loads climb.
Induction:
Well this gets a little stranger. Field amps "induce" a current to flow
in the Rotor. Ok amps in is X what amps are flowing in the rotor???
With the rotor locked, the rotor looks like a shorted turn in the
secondary of a AC transformer, Or like a short circuit. Limited only by
the copper resistance. To induce this current you need slip, or the
rotating field of the stator to have a different speed than the fields
in the rotor. OK... We want enough slip so that we get the max current
transfer in the rotor. This is close to the slip rating of the motor,
well it is for "name plate" torque.
What limits the current??? copper and the instantaneous slip. That
results in a "Not much" to the current limits. Not 1x not 2x not 5x not
10x, the stator currents, but some where's out there.
It is common for industrial 3 phase motors to create 10X the nameplate
torque on startup without a "Soft start" circuit. Not a issue in drag
racing. We crave this.
The trick is to keep the slip high but not too high all the way to the
finish.
So all those that think Ac has to be whimpy,
Not true.
Why no Hp Ac inveters, Well that's not what they were sold to do.
Efficient is what they are selling. Not brutal. With IGBTs it pays to
have as much voltage and as little amps as possible. Keeps the power
stage affordable.
Even a 600 amp 3phase power stage with programable Slip settings, and
current limits Set for Really big amps would be revolutionary in our
little EV drag racing corner. Heck 6 step with slip tables would be
interesting. It's amazing how much torque 12 volts of 6 step make on a 3
hp 3phase induction motor. Done that, been impressed. Hummmm.
Nope back to Green boxes.... it's where the checks come from now A Days.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
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Tom Hudson wrote:
>
> Would anyone with experience using Evercel's Nickel-Zinc batteries please
> contact me off-list (heck, even on-list would be OK, as long as nobody
> objects).
>
> The lead-acid batteries in our Solectria E-10 pickup are degrading (my wife
> hit reduced-power mode at 32Ah yesterday) and I want to get the ball rolling
> to replace them ASAP. Evercel's MB80-12-8 nickel-zinc batteries are a
> perfect replacement for the group 24 batteries that are in the truck now,
> and I'm willing to take the plunge.
>
> I'd like to talk to someone who has used these batteries so that I can get a
> better handle on what will be involved with the upgrade on our truck
> (cooling, Brusa charger profile, etc.).
>
> Even though the Nickel-zincs have much more capacity than the lead-acids,
> we're going to stick with two strings so that current draws are reduced
> during driving. The only concern I have about this is that the charging
> procedure specified in the Evercel website shows a constant 22A, and our
> charger isn't going to be able to put out more than about 20A, with each
> string seeing 10A. From what I've read in the detailed PDF on Evercel's
> website, this probably isn't a problem (may be better for the batteries).
> It should just mean a longer charge.
>
> I've asked Evercel for quotes, availability and lead times but so far
> haven't gotten a response (not encouraging).
>
> Anyway, if someone with experience in these batteries could contact me, I'd
> like to pick your brain a bit so I can get my truck upgraded. Thanks!
>
> -Tom
You can use bulk charge with a timed hold. It has worked for Evercells.
electriccabenergy.com should also beable to help since they import for
Evercell.
Heat is a issuse, plan on cooling the cells in the hot weather. In cold,
forget them, they love it.
I have 3 plus Evercell clients using my PFC chargers.
It works and rather well also.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
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Victor Tikhonov wrote:
>
> Lee Hart wrote:
>
> > > Induction motor has currents induced in bars due to slip, So much
> > > at start that heat is a major problem. What is the minimum frequency
> > > of an automotive sinewave(AC) drive?
> >
> > In the range of 2-3 Hz. They can't go much lower than this or there
> > isn't enough induction (transformer action) to produce enough rotor
> > current.
>
> Siemens drives have 0.7 Hz lowest frequency (spec is 0.7-400 Hz).
>
> Victor
Yea and that is a +- number they can go through 0 to reverse rotation
right??
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Rich Rudman wrote:
>
> Induction:
> Well this gets a little stranger. Field amps "induce" a current to flow
> in the Rotor. Ok amps in is X what amps are flowing in the rotor???
Stator amps * slip * K - faster stator flux crosses rotor - more
current induced. K depends on design.
> With the rotor locked, the rotor looks like a shorted turn in the
> secondary of a AC transformer, Or like a short circuit. Limited only by
> the copper resistance. To induce this current you need slip, or the
> rotating field of the stator to have a different speed than the fields
> in the rotor. OK... We want enough slip so that we get the max current
> transfer in the rotor. This is close to the slip rating of the motor,
> well it is for "name plate" torque.
> What limits the current??? copper and the instantaneous slip. That
> results in a "Not much" to the current limits. Not 1x not 2x not 5x not
> 10x, the stator currents, but some where's out there.
> It is common for industrial 3 phase motors to create 10X the nameplate
> torque on startup without a "Soft start" circuit. Not a issue in drag
> racing. We crave this.
> The trick is to keep the slip high but not too high all the way to the
> finish.
> So all those that think Ac has to be whimpy,
> Not true.
Yes. Software takes care of watching for slip and adjusts freq/phase
accordingly to have it optimal for torque demand at that moment.
Victor
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--- Begin Message ---
Rich Rudman wrote:
> > Siemens drives have 0.7 Hz lowest frequency (spec is 0.7-400 Hz).
> >
>
> Yea and that is a +- number they can go through 0 to reverse rotation
> right??
I don't know, it must be. Else I can't explain smooth transition.
May be 0.7Hz is specified as lowest still producing rated torque
(same as in flat const torque region). Below 0.7 Hz you don't get
this torque (and don't really need) but it still generates
any freq down to 0.
Victor
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--- Begin Message ---
> 250MPH and an indy car comes into the pit, you can place your hand on
> the gear - box, it is not hot.
Sorry, I don't believe it. I know for a fact that they run transmission
coolers. There would be no point if the trans ran below about 100C. Many F1 cars
switched from Magnesium to Aluminium because the cases were softening at running
temp.
Paul Compton
BVS technical officer www.bvs.org.uk
www.sciroccoev.co.uk
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The question was - to have smooth transition from neg to pos
freq it must be able to generate <1Hz freq, infinitely close to 0.
Yet the spec says 0.7 Hz min. Any clues?
Victor
Lee wrote:
And, with that DC flowing in the motor windings, they are likely to
saturate. When they do, inductance falls drastically. The inverter
depends on this inductance for its PWM and current limit to work. So,
the inverter can lose control of its current limit, and can't protect
itself at the time it needs it the most.
So, most inverters establish some minimum operating frequency, to avoid
these conditions. When the motor must operate at a lower speed (or in
reverse), they deliberately apply a higher-than-optimal frequency, but
limit the winding current and voltage to still produce torque.
The first paragraph answers "why." The second paragraph answers "how."
It can still work smoothly, so long as the inverter is able to
control the voltage and amps the motor sees. You get smoothness with
more rotor amps due to higher slip, but less stator amps due the the
inverter limiting it to control the output torque (after all, torque
is the result of the two magnetic fields interacting).
Inductance, the why, seems to be the same issue that the Curtis 1221b
controllers can have with certain motors (the ADC 9 inch seems to be
the worst offender). The B series Curtis controllers have about a
minimum on time of about 10%. At low motor speeds you could see about
80 battery amps - more like 800 peak amps across the FETs! This can
result in silicon popcorn pretty quick (after all, that controller
can only manage 150 amps continuous, and 400 amps for a short time).
Certainly, the Siemens inverters switch much faster. But if they
saturate the iron the rate of current rise when they (IGBTs, right?)
are on could prove dangerous to the inverter. Clearly Siemens is
concerned about building something that will last; they don't want to
go there.
Neon
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If the boards are PC/100 then try http://www.tri-m.com/ Tri-M systems. They
have a box called a cantainer that is a single extruded aluminum container
with rubber shock mounts. They have power supplies in the same form factor
and end plates pre-punched or blank as well as gaskets if water resistance
is needed. We used these in a university project (still do), one took a
dive from about 50' into the ground and all the electronics survived.
Lawrence
-----Original Message-----
From: Eric Penne [mailto:[EMAIL PROTECTED]
Sent: June 12, 2003 11:14
To: [EMAIL PROTECTED]
Subject: OT Question: Lots of Small Metal Enclosures
I have the need for 100-200 small metal enclosures approx. in a 9" cube.
Seeing as how this is a list of people that know lots of little resources,
I was hoping somebody would have a source for something like this.
The enclosure is for a single board computer which is a PC with everything
integrated used for embedded projects mostly.
Thanks
Eric Penne
[EMAIL PROTECTED]
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Chris and Peter both gave some of the tradeoffs about using a transmission
or not and both said that without a transmission you would need more
powerful batteries.
Is that really true? Maybe slightly, but I think for the most part, no.
Here's my reasoning:
If you want the same acceleration performance, you will need higher motor
currents without a transmission, but the voltage will be lower because the
motor is spinning slower. Ignoring inefficiencies for a minute, the actual
power required to accelerate a car at a certain rate over a certain speed
range is fixed. All of that power is coming from the batteries and should
be roughly the the same, with or without a transmission.
The actual power needed from the batteries could be a bit higher because
the motor and controller will probably be a bit less efficient trying to put
out
that much power at low RPM. Some of that efficiency might be regained by
the lack of a transmission, but that could be small (I would expect that to
be
a bigger advantage when calculating the overall efficiency of the car, not
just
the efficiency during acceleration). Anyway, I don't have any good data on
the difference in motor efficiency, but it seems to me the only time that
there
would be a really large difference in efficiency would be at really low
RPMs.
At low RPMs, the transmission based design is limited by motor current or
tire
spin, not battery current, so drawing a little extra from the batteries at
this
point to keep the same acceleration doesn't overstress the batteries. At
higher speeds, when acceleration is limited by the battery pack, the motor
and controller will be much closer to their peak efficiency, so the
difference
in efficiency between the two designs will probably be pretty small (a few
percent maybe?). Would that few percent be made up by not having to
shift? I don't know, but in any case, I suspect that the performance
difference
caused by not upgrading the battery pack would be very small and not really
a
factor in deciding whether or not to use a transmission.
I think the impression of a need for better batteries comes from the
likelihood
that those going to the effort to build an EV without a transmission are
also
willing to pay for better performance, so they get higher power batteries.
A
lead sled could be redesigned without a transmission but using the same
battery
pack and get nearly the same sluggish performance. Of course once you've
got
that high power motor and controller, it's really tempting to throw in some
high
power batteries. They won't help low end torque since you've probably
already
maxed you motor current limit, but you could get more midrange
acceleration...
-Michael
-- Peter VanDerWal said ---
...
So without a transmission you are stuck in 4th gear all the time. In
order to provide the same performance accelerating from a stop, your
motor now needs to provide about three times as much torque. This means
(for a series motor) that you will need somewhere between two and three
times as much current going into the motor. This means a more powerful
controller (more expensive). In order to avoid a melt down you will
also need either two motors (similar in size to the single motor with
transmission) or one much larger motor (again more expensive). Finally
you are going to need more powerful batteries to feed this
motor/controller combo.
...
-- Chris Tromley said --
...
Most people use a transmission in conversions because it's there (free).
Starting from scratch, you can get the same result using no transmission
with a high-amp controller and batteries.
...
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