EV Digest 5389
Topics covered in this issue include:
1) Re: 6 hp. Motor Needed
by Lee Hart <[EMAIL PROTECTED]>
2) Re: Switched Capacitor Equalization of Long Strings WAS: Some problems
to solve
by Lee Hart <[EMAIL PROTECTED]>
3) Re: VW Beetle
by John Norton <[EMAIL PROTECTED]>
4) Re: Switched Capacitor Equalization of Long Strings WAS: Some problemsto
solve
by Lee Hart <[EMAIL PROTECTED]>
5) Re: longest range?
by John Wayland <[EMAIL PROTECTED]>
6) Re: Have been collecting range data, how about acceleration data
by "Mike Phillips" <[EMAIL PROTECTED]>
7) Re: Some problems to solve
by Lee Hart <[EMAIL PROTECTED]>
8) Re: Some problems to solve
by Lee Hart <[EMAIL PROTECTED]>
9) Magnetic Pickups
by "Ryan Stotts" <[EMAIL PROTECTED]>
10) Re: Some problems to solve
by "Joe Smalley" <[EMAIL PROTECTED]>
11) Re: 6 hp. Motor Needed
by "jmygann" <[EMAIL PROTECTED]>
12) Re: longest range?
by Victor Tikhonov <[EMAIL PROTECTED]>
13) Re: Have been collecting range data, how about acceleration data
by "Paul G." <[EMAIL PROTECTED]>
14) OT: Motors and 14-50 plugs
by "Chris Tromley" <[EMAIL PROTECTED]>
15) RE: Switched Capacitor Equalization of Long Strings WAS: Some pro
blemsto solve
by Cor van de Water <[EMAIL PROTECTED]>
16) RE: Motors and 14-50 plugs
by Cor van de Water <[EMAIL PROTECTED]>
17) RE: Some problems to solve
by Cor van de Water <[EMAIL PROTECTED]>
18) Battery comparison- Thanks for the answers.
by "Richard Acuti" <[EMAIL PROTECTED]>
19) Re: longest range?
by Mike Chancey <[EMAIL PROTECTED]>
20) Re: longest range?
by Jeff Shanab <[EMAIL PROTECTED]>
21) Re: longest range?
by John Wayland <[EMAIL PROTECTED]>
22) Re: Have been collecting range data, how about acceleration data
by "steve clunn" <[EMAIL PROTECTED]>
23) Re: Battery comparison- Thanks for the answers.
by "Roland Wiench" <[EMAIL PROTECTED]>
--- Begin Message ---
jmygann wrote:
>
> Can anyone here recommend an electric DC motor (not wheel motor),
> that is about 6HP continuous, _very_ affordable, not too large, and
> well suited for regenerative braking (such as the discontinued Etek)?
>
> It's for my car project in
> http://autos.groups.yahoo.com/group/SmallEfficientVehicles
That's a nice-looking picture! I hope the prototype looks this good.
The cheapest way I can think of to get 6 HP continuous is a pair of golf
cart motors. If you use the newer separately excited ones, you'll have
easy regen.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Brad Baylor wrote:
>
> >What do you think of using switched-capacitance to equalize large
> >strings? (A la http://www.smartsparkenergy.com/batteq.htm)
>
> That is brilliantly simple! Why didn't I think of that.... gonna have
> to experiment now. The cheapest implementation would be relays,
> electrolytics, and a 50% duty cycle oscillator that can drive the
> relays. Maybe some resistors to prolong contact life. Wonder what
> frequency to run it at and what value components. Hmmm..
Try it before you build anything too elaborate. What you'll find is that
the initial current may be high, but it falls to essentially zero almost
immediately, long before the batteries are actually at equal states of
charge.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
On Tue, 18 Apr 2006 19:22, Alan Smith wrote:
A friend of mine wants to convert to an ev because he only drives about
10-15 round trip for work. And occasionally takes his kids places
around
town. The first question is, what car should he use as a donor? Now, I
know
almost nothing about cars, but I was thinking a VW Beetle because
they're
small and it shouldn't take much to power them. What do you all think?
There are a number of ev sites that have a donor selection faq. In
general, lighter is better, and you want a manual transmission. And it
needs to have some space to put batteries and a chassis that is up to
it.
There are other things like not wanting a rusty car (which you don't
want regardless) and some advice to pick a car you like, because if you
don't like it, your ev experience will be lesser.
The Beetle was originally a 36 hp car, so it doesn't take much to match
or beat the performance of those cars, though they were mostly more
powerful than that. They are simple, with few electrical needs, parts
are plentiful and cheap - a whole section of JC Whitney devoted to just
Beetle's. They have a certain style that a more modern small car lacks
- who covets a Geo, for example? Not downing Geo's, just on a desire
level, there is no comparison.
All of that being said, the downside is that these are 30 to 40 year old
cars. Finding one in decent shape could be a challenge, especially if
you are on the East coast. One that has been restored to a very good
condition is likely to be $5k or more - sometimes much more. Plus, they
lack many safety features we take for granted - a lot don't have rear
seat belts or shoulder belts in the front, a lot have drum brakes all
the way round that would be scary slowing a car a thousand pounds or so
heavier than designed, so you'd have a further expense and difficulty
upgrading that. I'm not a bug expert, but I think a super beetle takes
care of most of those issues.
In my search for a donor car, I have just about ruled out a beetle
barring some incredibly lucky barn find of a great body sans motor that
someone wants to sell cheap nearby.
There are any number of newer, relatively light manual transmission
vehicles with disc brakes etc. Hondas, toyotas, nissans, escorts, geos,
vw rabbits, etc. in decent enough condition for under $2k - remember
you are adding $5-10k to the car, so unless money is not important to
you, a cheaper donor is better.
Another thing to take into account is the availability of adapters -
seems to me that this is the hardest part for a do-it-yourselfer.
Beetle conversions are plentiful, so they are available. You can check
out Electroauto and KTA and cloudelectric for what they already have
plans for. They are relatively pricey, but unless you have a metal shop
in the grarage, chances are it is still cheaper than the time you would
spend yourself. I know it can be done, it all depends on how much time
vs money you want to spend.
As for lead acid, surrounding yourself with half a ton of hazardous
materials sounds like a bad idea, but it is what it is. Probably
comparing to the explosive power of a tank of gas won't win that
argument, but I bet a look at the price of exotic batteries (at this
point) would.
Probably sealed batteries might sound less scary, and there are plenty
of people running them.
John F. Norton
via T-Mobile Sidekick
--- End Message ---
--- Begin Message ---
Brad Baylor wrote:
>
> >This is the old "flying capacitor" circuit. It's been invented and
> >re-invented many times. It is a good idea that doesn't actually work
> >very well.
> >
> >The basic flying capacitor circuit winds up dissipating about half the
> >power in the resistance of the switches. And, to move any significant
> >amount of charge, the capacitor has to be enormous or the switching
> >frequency has to be very high.
>
> Damn.. I knew there had to be a catch. Yeah I was kind of wondering
> about that, with no inductors in the circuit. I wonder how hard it
> would it be to add inductors or transformers to reduce resistive
> losses? Hmmm..
Certainly you can add inductors. When you have one transistor, one
diode, one inductor, and one capacitor per battery, you have the basics
for any of the standard DC/DC converter circuits (buck, boost, etc.).
The challenge, as always, is to build one that is simple, inexpensive,
reliable, and that actually works.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Hello to All,
Victor Tikhonov wrote:
I know you can have a la Red Beastie lead sled built to
demonstrate a range number rather than be a normal commuter,
but it's not exactly what most people would want to drive).
(Don't get me wrong, I respect Dick Finley's creation very much).
From Roger Stockton:
In all fairness, I think that Victor's comment still stands.
The Red Beastie got about 2x the range of a typical conversion, and used
2x the amount of batteries...other aspects of performance suffered as a result:
this was a 5000lb
2-person vehicle with reasonably slow acceleration despite a decent
motor and controller combination.
I agree with both of your assessments. The truck was actually even
heavier, at exactly 5290 lbs. It's acceleration was borderline, it was
very heavy and felt cumbersome to drive, it slowed down on steep hills,
and it took forever to get up to near 90 mph, but amazingly it 'did'
reach the very high 80s on level ground. On the other hand, it was also
capable of towing a 16 ft. tandem wheel trailer loaded with my 2300 car,
the 500 lb. Heavy Metal Garden Tractor, and a generator plus tools and
stuff, at 55 mph from the east side of Portland south to Woodburn, OR, a
45 mile trip, and it still had about 30% charge left.
Victor, I think you and Dick would have liked each other.
See Ya.......John Wayland
See a video of Red Beastie in action (19th thumbnail down from the top
of the page) at the Plasma Boy website:
http://www.plasmaboyracing.com
--- End Message ---
--- Begin Message ---
USE Truck, 50kw AC. 0-45 14.86 sec. 1400lbs of batterys. Driver only.
Vehicle wt about 4000-4400lbs w/o driver.
AC Propulsion Saturn 100kw AC. 0-45 6.00 sec. and 0-60 9.46 sec. Both
times with 470 lbs of driver and passenger. 1200 lbs of batts. Longest
drive 79 miles. Vehicle wt about 3400lbs.
Mike
--- End Message ---
--- Begin Message ---
"Matthew D. Graham" wrote:
> Apparently, I am one of the poor, unfortunate souls with 25 Orbitals
> that just can't seem to agree on a common voltage... I have quite a
> few that hit the 14.8 V mark and start blinking while others want to
> hang out around 13 and small change.
That suggests that they are not equalized. The variations between them
might even be large enough that you *can't* equalize them with your
present method.
> Anyway, all this talk of equalization finally got me inspired...
> After topping up the pack with a normal charge cycle to about 345 V,
> I followed the equalization procedure, but chickened out after about
> 40 minutes. Some of the batteries got up around 15.5 V, while half
> of the pack's batteries were still wallowing around 13.2 V... at a
> charge current of 1 amp and pack voltage got to about 360 V.
This suggests to me that they *still* aren't equalized.
> Needless to say, hearing today that I should NEVER equalize my pack
> of Orbitals kinda bummed me out
What matters most are the AMPHOURS you put in at high voltage. Your
15.5v for 10 minutes at 1 amp is no problem at all; that's only 0.16
amphours.
> what's the best way to get all the batteries in line?
Charge them INDIVIDUALLY to the same ending voltage and current.
> I'm not a fan of charging individually since I've done it before
> with only short term satisfaction. The batteries soon get out of
> whack again.
Correct. This tells you that your present balancing system is inadequate
for the amount of imbalance in your pack. You need batteries that are
more closely matched, or a "stronger" balancing method.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Cor van de Water wrote:
> Any opinions on this way of "equalizing once a month"?
It sounds like your batteries are reasonably well equalized. I see about
a +/-0.025v difference between highest and lowest with a pretty
aggressive balancer.
But, you are doing your balancing via deliberate overhcharging, as would
be done with floodeds. This works for a while, but you will discover
that it shortens your battery life. Over time, they will dry out and
their internal resistance will rise (i.e. larger voltage sag under
load).
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
http://www.markwilliams.com/driveshaftPickups.aspx?CategoryID=266
--- End Message ---
--- Begin Message ---
It appears that your pack is getting full on nearly every cycle.
The slight overcharge appears to come close to meeting John Olson's negative
plate charge requirement.
The batteries appear to be very well matched.
As Bill Dube' stated, you are running a compromise between sulphation and
dryout tending more toward sulphation than dryout.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Cor van de Water" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, April 18, 2006 3:14 PM
Subject: RE: Some problems to solve
> OK, I have AGM's and I >do< equalize them, though some on this list
> disagree that this is truly an equalization, but the question is
> always: what is lore and what is data, so I'll present the data
> that supports my story...
>
> My pack is 26 AGMs in 1 string (312V) of 110 Ah.
> I charge them every night except when they still are over 80%
> (standard commute is 23 miles round trip which brings them to
> 60% but sometimes I work from home or only make a 3 miles trip
> to church or supermarket)
> This charge is a fixed 7 hours to 356V (13.7 per battery) at
> maximum 10A and tapering off to 0.5A after 7h.
> This is the factory recommendation for float charge.
> Once a month or so I will cranck the voltage up to 385V
> (14.8V per battery) at the end of the float charge, with a
> current limit of 3A to allow the batteries to recombine all
> gas that might be produced.
> I see that for a while the voltage is rising slowly from
> 356 to about 365V, then quickly shoot from 365V to 385V after
> which the current starts falling.
> When I perform this procedure at the end of the float charge
> (batteries sitting at 356V 0.5A for hours) then the voltage
> immediately goes to 385V while the current limit never engages
> for more than a short moment.
> This tells me that my batteries are pretty well equalized with
> the long float charge.
>
> To validate this idea, I measured all batteries I cound reach
> and found them all within 20mV from each other in charged state
> (13.25 - 13.27V)
>
> Any opinions on this way of "equalizing once a month"?
>
> BTW - I have no regs, batteries are 3 months in service, 2000 miles
> and arrived with approx 200 mV difference between them.
>
> Regards,
>
> Cor van de Water
> Systems Architect
> Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Proxim Wireless Networks eFAX: +1-610-423-5743
> Take your network further http://www.proxim.com
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Rich Rudman
> Sent: Tuesday, April 18, 2006 10:21 AM
> To: ev@listproc.sjsu.edu
> Subject: Re: Some problems to solve
>
>
> For the ground rules Sake...
>
> Lets assume the brute force method is out of the question.
>
> And you don't want to just force 2 amp into a full battery. The result
will
> cause venting.
>
> So.. What else do you have?? Voltage? and Amps...These are the only two
> tools to read and to vary.
> Unless you are also tracking past demand and charge cycles.
>
> So.. You pick a voltage that will fill the battery on time and not vent
it.
> AGM and specifically Optimas recommend 14.8 volts. Seams to work for most
> AGM batteries.
>
> That old Bucket of water concept is very valid. but you want them all
full,
> no matter if the buckets are slightly different sizes. Full and barley
> dribbling over is a Known state.
> Locking the peak voltage with any kind of regulator.. is a very good first
> step. The second is to back off the main charger If you can't dribble the
> extra power fast enough to keep the voltage
> below the level you want them at.
> Or adding power to the ones that just take a little longer to
> dribble...Good idea helps get to that nice all full state faster. Without
> having to abuse any single battery with high volts like the Bulk 2amp for
> ever stage that some Battery vendors and Charger designers favor. Heck Lee
> if these old concepts actually worked like folks say they do...we wouldn't
> be making Chargers and BMS improvements now would we?
>
>
>
> 14.8 is going to "Gas" the internal chemistry.. But not such that venting
> will occur. Well to any great degree. I have vented at 14.8 after a 150
amp
> cycle.. there are limits...
>
> But to most EVers that are coming over from Flooded PbLa.. You don't want
to
> push a AGM through the "classic" equalization cycle. We have to do it by
> other means.
>
> The other means for AGM is a voltage hold While the amps taper back to
less
> than 2 amps. You NEVER drive the AGM over 15 if you can help it. Doing so
> with a long series string just about guarantees you will vent one of the
> batteries. There are clear exceptions to this rule.. But if you do just
> what the procedure says, you will get rated cycle life if not a couple
times
> more that the posted cycle life.
> Since the advertised cycles assumes you will have some... "Events".
>
> Knowing the Actual requirements of a single Battery's State of charge...
> Well Lee that's just about impossible. You need a LOT of solid lab grade
> data, as well as the history of the last charge cycle and depth of
> discharge, Age of battery and the number and depth of all cycles. And then
> with some math and a Good WAG... you can kinda predict the Watts needed to
> solve the equation. Yup you can get close with a good data cruncher and
> "Best practice" methods. Been there done that.. by hand many times.
>
> Or you can hold all the regs at blink levels for 30 minutes.. and yer
> done...
>
> I am not sure..which one gives a better charge... But.. I really do know
> which one is more cost effective....
> And which one is easier to implement.
>
> Rich Rudman
> Manzanita Micro
>
>
>
> ----- Original Message -----
> From: "Lee Hart" <[EMAIL PROTECTED]>
> To: <ev@listproc.sjsu.edu>
> Sent: Tuesday, April 18, 2006 9:11 AM
> Subject: Re: Some problems to solve
>
>
> > Rich Rudman wrote:
> > > Forget forced equalization. That's for floodeds. AGM guys use the
Regs.
> > > And Never drive the Lead over 15 volts if we can help it.
> > > Never Equalize, The regs do that as they blink.
> >
> > Rich, I disagree.
> >
> > "Equalization" is the process of somehow getting different numbers of
> > amphours into batteries, to compensate for them being at different
> > states of charge. There are lots of ways to do it; your regulators are
> > only one.
> >
> > Ye Olde Brute Force method, used for floodeds, is to just blindly charge
> > excessively. Like filling buckets with a hose. They all fill up all
> > right; but the excess spills on the ground and makes a mess. With
> > batteries, the "mess" is gassing, fizzing, water loss, higher battery
> > temperature, and somewhat shorter life.
> >
> > You're right; you don't want to use this method for sealed batteries.
> > The top is "sealed", so attempting to overfill it causes the pressure
> > inside to increase. It can blow the safety vents, lose water (which
> > can't be replaced), make them get hot, and seriously shorten their life.
> >
> > But, I disagree that you *never* take AGMs up over 15v. Let's assume you
> > are doing your equalization via extra charging. If one battery is 1
> > amphour lower than the rest, you have to put one extra amphour into it.
> > There are lots of ways you can do this.
> >
> > You could apply a lower voltage for a longer time. My simple zener-lamp
> > regulators start shunting current at 13.5v, and gradually increase to
> > 0.5 amps at 15v. Let's say the average is 0.25 amps. It takes 4 hours to
> > get from 13.5v to 15v; so they are providing 0.25a x 4h = 1 amphour of
> > equalization without ever reaching 15v.
> >
> > Or, you can charge to a higher voltage but limit the time. 15.5v at 2
> > amps for 30 minutes is also 1 amphour. In fact, there is evidence that
> > higher currents do a better job of equalzation. Hawker suggests
> > equalizing at 2 amps with *no voltage limit*, for example. The key here
> > is that you need to *know* that there is room for that extra 1 amhour.
> > You don't blindly charge at 15.5v and 2 amps into an already-full
> > battery; that will only force it to gas; the internal pressure goes up;
> > it gets hot, vents, loses water, and is damaged.
> >
> > The key for AGMs is not to blindly hold some voltage limit; but to
> > *know* the state of charge, and put in the *right* amount of overcharge
> > to bring it to full. The actual voltage and current you apply to do this
> > has rather wide limits.
> > --
> > Ring the bells that still can ring
> > Forget the perfect offering
> > There is a crack in everything
> > That's how the light gets in -- Leonard Cohen
> > --
> > Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
> >
>
--- End Message ---
--- Begin Message ---
Where can I find "the newer separately excited ones" ?
--- In [EMAIL PROTECTED], Lee Hart <[EMAIL PROTECTED]> wrote:
>
> jmygann wrote:
> >
> > Can anyone here recommend an electric DC motor (not wheel motor),
> > that is about 6HP continuous, _very_ affordable, not too large,
and
> > well suited for regenerative braking (such as the discontinued
Etek)?
> >
> > It's for my car project in
> > http://autos.groups.yahoo.com/group/SmallEfficientVehicles
>
> That's a nice-looking picture! I hope the prototype looks this
good.
>
> The cheapest way I can think of to get 6 HP continuous is a pair
of golf
> cart motors. If you use the newer separately excited ones, you'll
have
> easy regen.
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in -- Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377,
leeahart_at_earthlink.net
>
--- End Message ---
--- Begin Message ---
John Wayland wrote:
See a video of Red Beastie in action (19th thumbnail down from the top
of the page) at the Plasma Boy website:
http://www.plasmaboyracing.com
I saw the video, thanks John.
What a stupid comment of the TV show host about leaving on
Friday and get to the Mt. Hood on Sunday in an EV! These
unfortunate comments of ignorants spoil the image of EV.
Victor
--- End Message ---
--- Begin Message ---
On Apr 19, 2006, at 6:48 AM, John Wayland wrote:
I was excited to see this request for acceleration specs, until I
realized my car has to be excluded :-(
Steve wrote:
I would like to put together a spreadsheet with some real data on
acceleration. I am looking for acceleration data in the range of 4 -
40 sec for 0 - 45 MPH with cars / trucks between 1500 lb and 5500 lb.
Don't feel bad, my buggy has been excluded too <g>
Paul "neon" G.
--- End Message ---
--- Begin Message ---
Hi Folks,
A change of employers has put me way behind on the list (again). I
will catch up eventually, but the new employer is working on a problem
I thought the list gurus might be able to shed some light on. I
certainly haven't had much luck with search engines.
We have a 5 or 6 hp 240 VAC hydraulic pump motor we'd like to power
from a 14-50 outlet. You'd think a 14-50 could put out around 12 hp
(even derated to 80% for continuous draw from the outlet), but the
specs on a Hubbell receptacle or plug are only 3 hp. It seems all
such outlets are similarly rated.
Does anyone know if this is a UL or NEC mandated limit? My guess is
that a motor starting under load would draw a big current spike as it
starts, causing arcs on the contacts that might turn into significant
resistance (and heating) after many repetitions.
Am I on track here? If it's not a hard-and-fast code rule I'm
thinking our specific application, which always starts the motor
unloaded, would work just fine. Am I missing something? Even if
testing proved it workable, would local code enforcers refuse to
approve it?
Chris
--- End Message ---
--- Begin Message ---
Lee,
Adding an inductor should not significantly change the
price of this circuit ;-)
That should improve the efficiency, but not by a terrible amount
as the no-loss case would have the capacitor voltage changing
maximum 2x the difference between the two batteries, so in effect
there is double the charge transported in the best case, in the
worst case (LC timing much shorter than switch frequency) the same
charge is transported in the C but the excessive dissipation in
the C and FET are avoided, comparable to PFC (Power Factor Correction)
in other words - there is less current draw, more gets transported.
So the idea is to make a version that has low current draw and leave
it running forever - that should take care of the issue of balancing
in days...
When the circuit is running always, it will run also when it matters,
during charging (equalising) and under load. Any difference in
voltage under any of these conditions should result in the lowest
battery getting current supplemented from 2 sides.
Using the simple formula for charge calculation to find a value for C:
I x t = V x C
say we want 1A of equalisation when the batteries are 1V out of whack
and switching frequency is 100 us (10 kHz) then capacitor calue is
100 uF.
To get a low ESR we may want to use 35V versions iso 16V which should
do the job, check your supplier's specs to find the best version.
The L-C circuit's fresonant frequency should be significantly above
10 kHz, so the value for the L should be below 1 uH but it must be
wound with thick enough wire to take several amps.
If you worry about this circuit running your batteries low if you
leave your EV for a longer time, then theoretically it should be
sufficient to hook up an intelligent charger to *one* battery of
the pack (preferably near the middle of the string) to have the
equaliser distribute this charge over all batteries...
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Lee Hart
Sent: Wednesday, April 19, 2006 7:28 AM
To: ev@listproc.sjsu.edu
Subject: Re: Switched Capacitor Equalization of Long Strings WAS: Some
problemsto solve
Meta Bus wrote:
> What do you think of using switched-capacitance to equalize large
> strings? (A la http://www.smartsparkenergy.com/batteq.htm)
This is the old "flying capacitor" circuit. It's been invented and
re-invented many times. It is a good idea that doesn't actually work
very well.
The basic flying capacitor circuit winds up dissipating about half the
power in the resistance of the switches. And, to move any significant
amount of charge, the capacitor has to be enormous or the switching
frequency has to be very high.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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Chris,
Most likely the issue is that the 14-50 is specified
to be used with either 120 or 240V so the power is
chosen at the safe side.
You can see this when looking at the 15-50 plug, just by
twisting one blade you suddenly get 7.5 HP and the voltage
is specified as 240V.
BTW in Grainger's catalog the 14-50 is even only 2 HP!
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
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Fax: +1 408 731 3675 eFAX: +31-87-784-1130
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Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Chris Tromley
Sent: Wednesday, April 19, 2006 3:44 PM
To: ev@listproc.sjsu.edu
Subject: OT: Motors and 14-50 plugs
Hi Folks,
A change of employers has put me way behind on the list (again). I
will catch up eventually, but the new employer is working on a problem
I thought the list gurus might be able to shed some light on. I
certainly haven't had much luck with search engines.
We have a 5 or 6 hp 240 VAC hydraulic pump motor we'd like to power
from a 14-50 outlet. You'd think a 14-50 could put out around 12 hp
(even derated to 80% for continuous draw from the outlet), but the
specs on a Hubbell receptacle or plug are only 3 hp. It seems all
such outlets are similarly rated.
Does anyone know if this is a UL or NEC mandated limit? My guess is
that a motor starting under load would draw a big current spike as it
starts, causing arcs on the contacts that might turn into significant
resistance (and heating) after many repetitions.
Am I on track here? If it's not a hard-and-fast code rule I'm
thinking our specific application, which always starts the motor
unloaded, would work just fine. Am I missing something? Even if
testing proved it workable, would local code enforcers refuse to
approve it?
Chris
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Hi Lee, Joe,
You agree that my batteries are well balanced, but I hear
conflicting info about the effect of my charging, if I hear
you correct Joe then you say that I routinely charge a little
too conservative (towards sulfation) while Lee indicated that
I may lose water and dry out my batteries.
My expectation is that I can do a 3-amp overcharge without
_venting_ any of the gassing that happens inside the battery
because I stay well below C/30 charge current when I get to
voltages that can cause gassing, that is why I charge full
current only up to 13.7V per battery and limit the current
to 3A when I get above that voltage (into 110Ah battery).
BTW Lee, the effect that I hear from others when their
batteries get dry, due to the increased acidity (high SG)
they have very stiff batteries but with reduced range,
can you explain why you say their internal resistance
will rise?
Joe Smalley wrote:
>It appears that your pack is getting full on nearly every cycle.
>The slight overcharge appears to come close to meeting John Olson's
negative
>plate charge requirement.
>The batteries appear to be very well matched.
>As Bill Dube' stated, you are running a compromise between sulphation and
>dryout tending more toward sulphation than dryout.
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Lee Hart
Sent: Wednesday, April 19, 2006 8:04 PM
To: ev@listproc.sjsu.edu
Subject: Re: Some problems to solve
Cor van de Water wrote:
> Any opinions on this way of "equalizing once a month"?
It sounds like your batteries are reasonably well equalized. I see about
a +/-0.025v difference between highest and lowest with a pretty
aggressive balancer.
But, you are doing your balancing via deliberate overhcharging, as would
be done with floodeds. This works for a while, but you will discover
that it shortens your battery life. Over time, they will dry out and
their internal resistance will rise (i.e. larger voltage sag under
load).
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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--- Begin Message ---
I appreciate the answers everyone gave to my questions.
You can laugh all you want at my initial suppositions (Hawker batteries
being "weak"). Why else would I ask the question? I didn't state it as a
fact, only as my admittedly flawed understanding of these batteries.
What I've taken away from all these repsonses is:
Orbitals, Optimas and Hawkers make great performance batteries (read: high
acceleration) because they can safely discharge at extremely high rates and
have little voltage sag when they do. However, you -may- sacrifice range
because they don't discharge as long. I imagine that the lighter a
conversion you can make, the less range you sacrifice.
Conventional floodeds and the NiCad's I asked questions about earlier have
the advantage of cost and long discharge times which are good for range, but
they don't tolerate high discharge rates well and experience voltage sag
plus extra weight so I should expect slower acceleration.
This information is very valuable to me as I determine what type of
batteries would be best for my particular application.
For those of you who may be curious, my "application" is:
A Karmann Ghia or similar car, with moderate to slow acceleration but a good
range of 55-65 miles with an available top speed of 65-75 mph. NO, I do not
expect to get 55 miles of range at 65 mph. I'm only talking about
"available" top seed and "available" range. I realize there is a speed/range
trade-off.
When I get to the point where I install batteries in my conversion, I
suspect I will select T-125's as they are the same dimensions as T-105's but
have a greater aH rating. If I had my druthers, I'd use T-145's but I'm not
sure I can keep the backseat and use a battery that tall. I'll have to talk
with some of the Karmann owners and see what I can get away with.
Rich A.
'81 Comuta Van
_________________________________________________________________
Dont just search. Find. Check out the new MSN Search!
http://search.msn.click-url.com/go/onm00200636ave/direct/01/
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John Wayland wrote:
I agree with both of your assessments. The truck was actually even
heavier, at exactly 5290 lbs. It's acceleration was borderline, it
was very heavy and felt cumbersome to drive, it slowed down on steep
hills, and it took forever to get up to near 90 mph, but amazingly
it 'did' reach the very high 80s on level ground. On the other hand,
it was also capable of towing a 16 ft. tandem wheel trailer loaded
with my 2300 car, the 500 lb. Heavy Metal Garden Tractor, and a
generator plus tools and stuff, at 55 mph from the east side of
Portland south to Woodburn, OR, a 45 mile trip, and it still had
about 30% charge left.
The component choices have changed quite a bit since the Beastie was
built. Things you couldn't go then you can do now. I wonder how it
would drive with the batteries wired in one 240 volt string with a
Zilla 1K for a controller? I don't think the performance would be
quite so tepid, though you would have to be careful on the battery
current. With all the settings available on the Zilla you might be
able to handle that too. Add on a PFC-50 for charging and you could
have a very awesome EV.
What do you think?
Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV List Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace)
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Sorry victor, I didn't mean to offend, I need to read the posts more
carefully (lots of activity lately, I read to fast)
"you don't get what you don't pay for" is really more a comment about
what ryan said about getting guged or scammed it is also a generic
statement I made up about everything in life when "you get what you paid
for" always made someone in the audience say wel.... not necessary....
I respect what you do and hope to be one of those customers in the next
year or 2 when I build my second EV.
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Hello to All,
Mike Chancey wrote:
John Wayland wrote:
I agree with both of your assessments. The truck's acceleration was
borderline, it was very heavy and felt cumbersome to drive, it slowed
down on steep hills, and it took forever to get up to near 90 mph,
but amazingly it 'did' reach the very high 80s on level ground.
The component choices have changed quite a bit since the Beastie was
built.
Ya think? Certainly, things are soooo much better nearly tens years
after Red Beastie was conceived and built!
Things you couldn't go then you can do now. I wonder how it would
drive with the batteries wired in one 240 volt string with a Zilla 1K
for a controller? I don't think the performance would be quite so
tepid, though you would have to be careful on the battery current.
Yup, excellent idea. I'd do the 240V pack and go with a Siamese 9
permanently left in series wiring mode and keep the 5 speed manual. The
Z1K is compact, yet very powerful. You could restrict battery current to
250 amps to protect the wet cells and give them the same very long life
(35k + est. miles on the Beastie's pack and still had 60+ miles range
when I sold it), but be able to send 1000 motor amps for the first 1/3
-1/2 the available motor rpm into the Siamese 9. This would make about 4
times the torque that I got with a single 9 inch at 450 motor amps.
Add on a PFC-50 for charging and you could have a very awesome EV.
Yes, that would have made charging so much better.
What do you think?
It's something someone might want to do. You'd still have a very heavy
conversion, but it would perform much better than the one Dick and I built.
See Ya.....John Wayland
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One way I compare different cars ( that I've had ) is to drive the car using
the amount of amp that is equal to the ah's of the pack( real usable ah's) .
Example my race truck 22 orbitals , batteries give 30 ah max , driving ,
using 30 amp it will go 32mph . My work truck with 2 strings of golf cart
batteries 200 ah , maybe 70 mph at 200 amps . this way you don't have to
compare 2 different numbers lime 30 miles at 55 mph compared to another 40
miles at 45mph ( what speed , what miles ) , . My Mercury Lynx would do 50
mph at 100 amp ( golf cart batteries with 100 usable ah;s) .
steve Clunn
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Hello Richard,
You will be happy with the T-125's or T-145's. I am running T-145's and I
never have to worry about my battery state of charge or what. I hardly look
at my battery performance any more, because I do not drive over 100 miles a
day. I normally under 50 miles a week and only charge about every 4 days
which the battery state of charge is still standing between 75 to 80 percent
and can charge them at 50 amps in with 20 minutes!!!
I am now at 4 years with the T-145's and they are still perfect and without
any BMS on them.
If I was running Orbital, optimas, or Hawkers, they would have be shot by
now.
Be sure when you order the T-125's or T-145's, you get a fresh batteries
dated all the same and not more than 1 month old. My batteries were only 2
weeks old strait from Trojan.
Also do not get the Low-Profile battery posts with studs, they do not stand
up to the torque and ampere that a EV may require. Get them with a buss bar
pad or a larger diameter post type. All mine post on my T-145'w are 1 inch
diameter at the bottom and taper to 7/8 to the top. The positive brass gold
plate battery clamps barely fit on these.
The battery truck drop off 50 batteries to me, and I tested all of them for
voltage difference, load test and specific gravity. I kepth the best 30 and
the local dealer took the other 20. Also watch for if any of the positive
post is darker then the others. Sometimes in transport, while the batteries
are stack on top of each other, a post may have leakage causing to darken.
Sometimes this will not show up until you charge it several times. If this
happens, then replace it with one of the other 20 batteries with the same
date.
If you do all the above, they should last a long time, I expect my T-145's
to last another 6 years.
Roland
----- Original Message -----
From: "Richard Acuti" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Thursday, April 20, 2006 5:36 AM
Subject: Battery comparison- Thanks for the answers.
> I appreciate the answers everyone gave to my questions.
>
> You can laugh all you want at my initial suppositions (Hawker batteries
> being "weak"). Why else would I ask the question? I didn't state it as a
> fact, only as my admittedly flawed understanding of these batteries.
>
> What I've taken away from all these repsonses is:
>
> Orbitals, Optimas and Hawkers make great performance batteries (read: high
> acceleration) because they can safely discharge at extremely high rates
> and
> have little voltage sag when they do. However, you -may- sacrifice range
> because they don't discharge as long. I imagine that the lighter a
> conversion you can make, the less range you sacrifice.
>
> Conventional floodeds and the NiCad's I asked questions about earlier have
> the advantage of cost and long discharge times which are good for range,
> but
> they don't tolerate high discharge rates well and experience voltage sag
> plus extra weight so I should expect slower acceleration.
>
> This information is very valuable to me as I determine what type of
> batteries would be best for my particular application.
>
> For those of you who may be curious, my "application" is:
>
> A Karmann Ghia or similar car, with moderate to slow acceleration but a
> good
> range of 55-65 miles with an available top speed of 65-75 mph. NO, I do
> not
> expect to get 55 miles of range at 65 mph. I'm only talking about
> "available" top seed and "available" range. I realize there is a
> speed/range
> trade-off.
>
> When I get to the point where I install batteries in my conversion, I
> suspect I will select T-125's as they are the same dimensions as T-105's
> but
> have a greater aH rating. If I had my druthers, I'd use T-145's but I'm
> not
> sure I can keep the backseat and use a battery that tall. I'll have to
> talk
> with some of the Karmann owners and see what I can get away with.
>
> Rich A.
> '81 Comuta Van
>
> _________________________________________________________________
> Don't just search. Find. Check out the new MSN Search!
> http://search.msn.click-url.com/go/onm00200636ave/direct/01/
>
>
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