EV Digest 3984
Topics covered in this issue include:
1) Re: The Amazing Little Hawkers.
by Chris Zach <[EMAIL PROTECTED]>
2) RE: Hybrid truck musings
by [EMAIL PROTECTED]
3) More hybrid truck musings
by Jeff Shanab <[EMAIL PROTECTED]>
4) Re: The Amazing Little Hawkers That Refuse to Die!
by John Wayland <[EMAIL PROTECTED]>
5) Re: Range + Golf cart vs. AGM wars
by John Wayland <[EMAIL PROTECTED]>
6) Re: More hybrid truck musings
by "John G. Lussmyer" <[EMAIL PROTECTED]>
7) Re: Motors in series? Torque vs. power?
by "Rich Rudman" <[EMAIL PROTECTED]>
8) Re: Range + Golf cart vs. AGM wars
by "Bob Rice" <[EMAIL PROTECTED]>
9) Re: The Amazing Little Hawkers.
by "Rich Rudman" <[EMAIL PROTECTED]>
10) Re: The Amazing Little Hawkers That Refuse to Die!
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
Within reason, you can pretty much whack AGMs with any voltage and
current you want during the bulk phase. In fact, if you watch out for excessive
heat, you can even pump in UNreasonable amounts of current - in the
hundreds of amps.
I totally and completely agree with that. Really. One million percent.
There's just one tiny problem:
How do you know when an individual battery in a string has hit the end
of the "bulk charge"?
That's the unknown, and I think that's where the problem is. If you have
a pack of 25 batteries, and battery number 18 in there is a trifle bit
different from it's neighbors, then it may hit the end of bulk charge a
bit before it's neighbors. Since that's one battery out of 25, you might
not see that it went over 14.7 while it's friends are all at 14.0 if the
only thing you count on for telemetry is battery voltage.
Battery #18 will see the full current in the string since it's a series
string and current is the same in a series string but it will be at it's
higher voltage than the others and will start to gas. Once it gasses,
even for a little bit, it loses water (then the other batteries hit 14.7
and the charger throttles back). Next time you charge, this battery will
be a bit lighter, and will charge a tiny bit "faster" because less
water=higher sulphuric acid ratio in there. And it will hit that sweet
point a bit earlier. Each time you charge, it will slide further out of
whack with the rest of the pack.
Does the above make any sort of sense?
It's during that last 20% of the charge that you need be concerned - and with
CURRENT more than voltage. Once a given cell is above the gassing
voltage, the more current that you give it, the more it gasses. If the gassing
is slow enough that the recombination reaction can keep up with it, all is
well.
Right. Which is why I think one can charge at 2.5amps using the dopey
Dolphin "safely". The recombiners can keep up with this apparently, but
they can't keep up with 20 amps. I think that was the Dolphin idea, and
in theory it should work great.
Also why I ask about lowering the voltage setpoint from switching from
bulk charge to finish charge rate. That's the only window I have in my
pack at the moment, and if I drop down from 362.50 to 350 say for this I
reduce the chance of "clipping" a battery. By lowering the bulk current
at the start, I also limit the damage somewhat if a battery was really
weird. Though the more I think about it, if one battery goes above 14.7
while the pack itself is at 14.0 average (350) then maybe it's time to
drop the pack anyway.
Except for this "Hawkers *REQUIRE* that you charge at high rates during
bulk" thing. Why? To what level? Can I charge at high rates for 5
minutes of the charge to "blow off the electrons" or whatnot then crawl
back into my lower-current pit of comfort? How about 30 seconds of
charge at 6C (150a regen, assuming the pack is unbalanced 99% one
string, 1% the other)?
Again you have missed a crucial point here. No, it is NOT around 0.5 amps
per string. You can't be sure that one amp from your charger is dividing
equally between the parallel strings. It's quite possible that 0.99 amps is
flowing through one string, and 0.01 amps through the other. The charger
should limit the equalization current to no more than the value that's
acceptable for ONE string.
*nod* I was assuming that 1 amp (actually .8a IIRC) is safe for a 26ah
battery so that it won't gas. I can test this easily enough; take a
Hawker out to the woodshed, remove the top (so the cell nipples will pop
off if it gasses) and charge away using my 1 amp constant
voltage/current bench power supply. If I can make the nipples pop, I'm
gassing.
Two packs, going on three. These are expensive lessons, aren't they? Been
there, done that, still learning. IMO, it sure would be nice if we could just
lease and maintain battery boxes with chargers and BMSes built into them.
That way we could pay somebody (presumably knowledgable) to ensure that
the charge algorithms were correct, that the battery was always meeting its
minimum specs, and that it was properly fixed if/when it wasn't.
Yes, they are expensive. And I hope this pack lasts longer. Even so, 6k
miles is not the end of the world; I've read about people flattening US
battery floodeds in 8k. And it's an AGM pack, so it makes for a fast
little car. I'd just like to understand *why* the pack blows up ultimately.
Chris
--- End Message ---
--- Begin Message ---
That's a great idea! It sounds like it would save a lot of unsprung
(sprung?) weight. What is an add-on transfer case. I don't know a lot about
4x4 vehicles so talk to me Barney style ;-)
Thanks,
John
-----Original Message-----
From: Jeff Shanab [mailto:[EMAIL PROTECTED]
Sent: Wednesday, December 29, 2004 9:54 AM
To: EVlist
Subject: Hybrid truck musings
How's this for an idea.
change the transmission to a 4x4 or use an add on transfercase
(depending on year and make)
forget the front axle, just put the motor where the front driveline was.
Now just put it in 4x4 and use EV controller
or even better, run ICE as FWD and then you can disconnect it from use
from inside the cab
--- End Message ---
--- Begin Message ---
My previous idea of using the 4x4 transfer case has some real issues
with rpm, the poor eletric motor would have to operate at drivleline speed.
Here is a wilder idea
Remount the engine 1" to 4" forward to allow for chain or belt from a
smaller eletric motor pully to an adapter sandwhiched between flywheel
and clutch.. This contans a one way clutch so the ICE motor isn't forced
to spin. The make roller sprags capable of this, but I don't know the
cost. The eletric motor can then lie parallel to ICE in engine bay. both
can use transmission and the eletric motor can be chosen as one that can
handle regen, if the person wants a small pack.
You could even start the ICE while in motion then just step on the old
gas pedal to lock in the clutch
Anyone know about locking torque converters, couls it be fitted into
this kind of application?
--- End Message ---
--- Begin Message ---
Hello to All,
Lee Hart wrote:
> Say you have 1200 lbs of golf cart batteries. At 65 lbs each, that's
> about 18 65 lbs batteries; a 108v pack. Your peak power is about 108v x
> 500a = 54kw, or 54 HP. You can draw this for 5-10 seconds without harm.
>
> Now put this pack in a lightweight EV that weighs (say) 1200 lbs, and
> you have 50% battery weight. You'll have great range; 50-100 miles on a
> charge.
>
> If the car has a motor/controller/transmission combination that lets you
> stay reasonably close to peak power as you accellerate, such an EV is
> going to do a lot better than 0-60 mph in 20 seconds. Bob McKee's
> Sundancer had this 50% golf cart battery setup, and did 0-60 mph in 12
> sec.
Lee, I think you've got some figures wrong. A 2400 lb. vehicle with just 54 hp,
in no way,
will it hit 0-60 in 12 seconds! Even factoring in a good controller and the
awesome torque
of an electric motor, it's just not going to happen. The Datsun 1200 sedan only
weighed 1587
lbs. and with 15 more horses under the hood, 69 hp, it ran 0-60 in 14.5
seconds. How does
a car weighing 1000 'more' pounds, with 15 'less' hp, get to 60 mph nearly 3
seconds quicker?
Another thing to consider, is that the original subject of discussion, was
using golf car
batteries in a conversion, not a ground-up concept car like the flimsy, foam
board rolling science
project creation called the Sundancer.
> I think there is hope to improve the 0-60 mph times with some kind of
> booster pack to provide higher amounts of power for 10-15 sec. It might
> be supercapacitors, or a second pack of AGMs or some other technology.
True, but this only points out the limitations of the golf car batteries, and
would
require even more weight to be piled in an already over-weighted EV.
> Braking is of course unrelated to batteries. If you add tremendous
> weight and don't upgrade the brakes, of course they will be poor. But
> you can have great brakes in any vehicle; you just have design for it.
Yes, there are heavy production cars that weigh as much as the 3400-3500 lb.
golf car
battery conversion, but to get them to stop requires fat tires with lots of
grip,
something pretty much the opposite of what an EV needs to get the lowest rolling
resistance possible. If you take a late model Corvette (3400 lbs.) and replace
it's
315 ZR tires with skinny EV types, the braking distance would dramatically
increase.
Take a 3400 lb. golf car conversion and somehow, stuff the Corvette's
wide rims and super fat tires under it, plus redo the entire brake system with
huge
(expensive) four wheel disc rotors and four piston Brembo calipers and such,
and yes, it
will then have good braking, but the cost of your EV just skyrocketed by $4000,
and,
you've lost perhaps 1/4 your driving range per charge pushing the fat tires
down the road.
> Handling is the same. The proverbial "lead sled" is a car jammed way
> past its GVWR with badly-placed batteries. Its handling suffers,
> sometimes to the point of being downright dangerous. This can be fixed;
> it's just more work.
Yes, about the same extra dollars to do the braking system mods I've just
described.
> > Today's newest EVers want their conversions to accelerate, steer,
> > brake, and pull hills just like a regular gas car can.
>
> But, they also want the same range and economy as a gas car. This is all
> but impossible with AGMs or other expensive batteries.
OK, we agree on this. Those high power lithium cell packs like Cocconi's tZero
uses, sure
sound like a step closer, though.
> This is the great dilemma. You can't have it all. You have to decide
> what is important to you; and pick your batteries accordingly.
This was the whole point of my original comments about your battery chart. I
think that
it's very important to be as clear as possible, when discussing battery pack
options for
EV conversions.
AGMs like Optimas and Orbitals in a light weight, high voltage pack
can make an EV have terrific acceleration, handling, braking, top speed, and
good range,
but require expensive charging systems and aggressive (expensive) controllers
to make the
most of them. They are initially, more expensive when compared to golf car
batteries.
As they are are typically used, that is, at high currents, fast recharges, and
often
times, allowed to sit for long periods of time (as in EV show cars and sunny
day
type 'fun machines'), the higher quality AGMs offer very high power, long cycle
and
calendar life, and long range considering the higher average currents involved
with
spirited type driving.
6V golf car batteries are typically used in low performance applications, that
is, at low
currents, moderate
recharges, and most always used as a daily driver over 30-40 miles, 5 days a
week.
Flooded type 6V golf car batteries offer low initial cost, low power, long
cycle life, and
long range,
at the cost of a heavy conversion weight due to the number of modules to get up
to a
realistic operating voltage.
The pack is typically 1200 lbs. but only offers 45-55 hp with 400-500 amp
controller
limits imposed.
If you want to extract the high cycle life of 600-750 cycles out of them, it's
imperative
to keep the
current pulled from the pack to under 500 amps, but 400 o less is even better.
Choose your batteries with your eyes wide open. If 60's era VW bug type
performance levels
are OK with you,
then a heavy conversion with 120V worth of flooded type 6V golf car batteries
are the way
to go. For the least
amount of dollars out of your pocket, you'll get long cycle life and long range
per
charge. If, however, you
want your EV to perform well, you might consider other types of batteries.
Flooded type 6v
golf car batteries
will not give good range or good cycle life if forced to make your EV
conversion act like
a regular gas car
in terms of performance, and in fact, will not last as long or give as good
range as the
more aggressive and more
expensive AGM type high performance EV batteries.
See Ya......John Wayland
--- End Message ---
--- Begin Message ---
Hello to All,
I'm responding to this thread once more, not to drown out others, or impune
them in any
way. I realize there are newbies on this list looking for good advice though,
and I want
them to hear the straight scoop on what they can and should expect from a
heavy, lower
voltage golf car battery type EV conversion.
jerry dycus wrote:
> > One of Wayland's points seems to be (and I *hope* I
> > don't misquote or
> > misrepresent) that the lead sleds can only deliver
> > on their promise of long cycle
> > life and what not under special circumstances -
> > basically by babying them and not
> > demanding high power from them.
Yes, that's it in a nutshell. No misquoting or misrepresenting that I can
detect :-)
> John's a little biased towards AGM's because of
> the way he drives, shows his EV's and a good fit for
> him.
Actually, I'm biased towards 'any' battery type that can help one do a
conversion type EV
that in the end, doesn't have any oozing, spitting, or acid spray, any
corrosion, any lack
of vehicle utility, and provides terrific handling, braking, acceleration, and
hill
climbing ability. It doesn't have to be an AGM lead acid battery. However, for
the present
time, the AGM lead acid battery is an affordable solution that does fit.
>
> But it's a costly fit compared to GC batts as
> AGM's cost 3-4x what GC's do for a given range.
Real life comparo.....Blue Meanie with 8, 69 lb. 6V golf car batteries, a 552
lb. pack @
48V. Even with 1000 amp power draws, 0-60 was probably 20 seconds, range when
driven hard
was 15 miles, 25-30 when driven moderately, and up to 45 miles or so when
driven at
unrealistic, 25-35 mph constant speeds. Cost of the pack today, would be $520
or so. These
lasted about one year before they were done. The batteries absolutely had to be
placed
around the car where they were accessible for routine watering and the
cleansing of
corroding parts, so this compromised the design of the car, in that I could not
place
batteries anywhere I liked...I had to put them just so to accommodate their
special
requirements.
Same car with 13, 45 lb. 12V Optima AGM batteries, a 585 lb. pack @ 156V. With
1200 amp
power draws, 0-60 is in the low 6 second area, range when driven hard is 15
miles, 20-25
miles when driven moderately, and up to 31 miles or so when driven at
grandma-type 35 mph
constant speeds. Cost of the pack is around $1500 or so. These last about 5
years before
they are done, with the car driven at about the same amount per year as when it
had golf
car batteries. $1500 divided by 5 years, is just $300 per year, compared to the
golf car
batteries at $520 a year. Performance is enhanced nearly four fold! Because
they never
have to be watered and never, ever corrode anything, they are now placed lower
for a better
CG (better handing), and they are now placed in areas that make the car's
utility much
better.
> AGM's usually give about 75-80% of the energy of a
> GC per lb in all but 1/4 racing conditions.
Lee Hart pointed out, that if your discharge rate is
something like a C1 or even less, the AGMs offer more useable energy, and I
agree with
him. I don't know about the rest of you guys, but I don't know of too many 1/4
mile
racers that take an hour to get down the track.
>
> That siad, GC can deliver 800 amps so not as much
> of a slug as John says.
I disagree. The typical golf car equipped EV is a 120V setup in a conversion
type design.
That's at a minimum, 1200 lbs. of batteries. Pulling 800 amps from them is
harmful and
will dramatically shorten their life, cancelling their inherent advantage of
high cycle
life. That said....the pack will sag at 800 amps discharge to about 90 volts,
so that's
72 kw, or 75 hp or so using a typical series wound motor and controller combo. A
conversion vehicle able to 'safely' handle a 1200 lb. battery pack ends up with
a finished
weight of 3400-3500 lbs. 75 hp in a light weight vehicle, say 2000 lbs., is
marginal for acceptable
acceleration. As an example, a typical economy car from the early seventies
weighed 2000
lbs., but had more horsepower in the 90-100 hp range, and yet, ran 0-60 in a
tepid 13-15
seconds. Now, drop that to just 75 hp and you're looking at 0-60 in maybe 18
or 19
seconds or so...argghh! That kind of performance would be laughed at today,
with the
typical modern economy sedan capable of 0-60 in 9 seconds or less. Now,
consider that same
75 hp having to move a whopping 3400- 3500 lbs. of weight...in my book, this
still comes
out being a slug.
> Also as far as maintaince, AGM's do take some,
> charging is difficult as you need regs that have to be
> disconnected to equalize the batts + buying,
> installing, maintaining the regs.
The 5 year old Optimas in Blue Meanie are reg free. Using a PFC20 charger with
the 156V
pack, set to switch to constant voltage at 195V then stay there as it declines
the
amperage over a 15 minute time interval, the pack has stayed strong, has never
gassed to
the point of any noticeable misting or oozing at all (as evidenced in the still
sparkling,
mirror finish gold plated connectors), and for me, has been totally maintenance
free.
> On GC's, just put water in them to bring them back.
> On GC you just need to water them once a month,
> not a bad idea as they, like any batt, ICE, should
> inspected that often.
Agreed. That's their attraction. Charging is simple, and when they're newer,
they need far
less watering. As they age though, watering becomes more frequent
>
> While if you need reasonable performance, GC's
> cost 3-4 times less for a given range, cheaper
> equipment to charge and last longer in most cases.
As I've tried to point out, golf car batteries do not, give reasonable
performance. They
give 'substandard' performance as they are typically used in a 120V string.
0-60 in about 20 seconds is similar (but actually worse) to an old VW Beetle,
like someone
else just pointed out:
>You might think of an EV with golf car batteries as a 1960s-
>era VW in terms of driving character.
The early 60's VW Beetle, with a bit less than 40 hp or so, had terrible
acceleration,
so much so, that 40 years later, VW still has a hard time trying to win over
converts that
still remember their cars that held up traffic and were cussed at as they
clogged mountain
passes with long lines of cars waiting for their chance to get around them.
That kind of
bottom of the scale performance has now been attached to the electric car,
largely due to
heavy conversions with low hp levels and powered by heavy packs of golf car
batteries. Is this
the way we want people to think of the electric car?
> And in an EV range is more important than high 1/4
> mile times for 98% of EV users. Not that GC's are slow
> compared to most ICE cars.
While I agree that for most all concerned, quick 1/4 mile times aren't high on
their list, I
do think that most want their electric cars to be able to at least be adequate
when
compared to regular gas cars. Saying "Not that GC's are slow compared to most
ICE cars."
is really an inaccurate statement. Most ICE cars can do 0-60 in about 8-10
seconds,
period. Many, many of them, do it considerably quicker, and only a handful take
longer.
Show me one, just one golf car powered conversion that can do 0-60 in 15
seconds, let
alone 10 seconds.
It's not helping anyone at all perusing this EV Discussion List and considering
doing a conversion, to not tell it to them straight. Saying that an EV with
1200 lbs.
of golf car batteries that weighs 3100-3500 lbs. and at 800 amp draws still has
just 75 hp,
is 'not' slow compared to most ICE powered cars, is not telling them straight.
The more typical
EV with 1200 lbs. of golf car batteries and weighs 3100-3500 lbs., has lower
400-500 amp
draws and thus has even less hp at around 45-55 hp...55 hp to move 3500 lbs?
Come on,
this isn't even close to being like a gas car, it's far from it.
The straight scoop is, that you can build a dependable EV conversion based of
golf car
batteries that will get you from point A to point B, and you can do it
affordably, too.
This conversion will, however, be slow compared to most every other vehicle on
the road,
with similar acceleration to big diesel powered work trucks, and oh
yes....those early
60's VW Beetles. This is not to say that you won't enjoy such a vehicle, it can
still be fun.
You can become one with the laid back style of driving that accompanies a
modest type
vehicle, and you can be proud of the way you roll along without using any gas!
Red Beastie was a fun EV that was a challenge to drive in mixed traffic. I'd
take folks
for rides, and as we could stay right with traffic moving away from a stop
light, they'd
say, "Gee, this thing does pretty good." Then, I'd explain that I had my foot
to the floor
in order to just stay with other cars that were driven with very little
throttle. On hills
of any kind, the heavy conversion would fall back behind everyone. On
Portland's steep
Canyon Road, while the other vehicles would be flying up the hill at 55-65 mph,
I was in
the far right lane at 35 mph with the pedal absolutely floored. I'd be sharing
the lane
only with garbage trucks, loaded tractor-trailer semis, and or dozer hauling
flatbeds!
>Not to mention a lot more range in real world driving.
More range, perhaps, but again, only when the playing field between the two
battery types
being discussed, is dumbed-down to very low performance expectations so that
golf car
batteries can even compete. A 'lot more' range, though, not true. Example:
1200 lbs. golf car batteries at 120V and a 400 amp current limit in a small
pickup.
0-60 in 20 seconds, at an average 120 amp current draw @ 55 mph (that's 120
amps continuous
out of each battery) 60 miles range.
1200 lbs. of Orbitals in a triple series-parallel string at 120V and a 400 amp
current
limit in a small pickup. 0-60 in 19 seconds (more available voltage due to less
sag
at the same 400 amp level), at an average 120 amp current draw @ 55 mph (that's
40 amps continuous
out of each battery) 50 miles range. That puts the AGMs within 84% of the golf
car batteries...hardly
making the golf car batteries 'a lot more range in real world driving'.
To be fair, if I was willing to accept this low standard of performance, then
yes, I'd
choose the golf car batteries... 16% more range (only when at substandard
performance levels),
far less cost, simpler charging. This is why, contrary to others' opinions, it
was I who
talked Dick Finley out of Optimas and into Trojan T-105s for the Red Beastie
project. His goal
was long range using lead acid type batteries, and performance wasn't a
concern; cost was
also not an issue with him. Believe me, it's true. After his fantastic results
with his
Renault pocket rocket that ran on Optimas (a car I had a lot to do with) and
was a third
gear tire smoker, Dick was ready to buy 2500 lbs. of Optimas for Red Beastie.
For that
project though, flooded type golf car batteries were the best choice, and I
was able to convince
him that they would deliver better range at the low performance levels we had
envisioned.
> An EV with 40-50% of it's weight in GC will give
> good performance...
I disagree, and so would any automotive journalist or car enthusiast of any
kind.
0-60 in 20 seconds or more, and slowing down on hills while you've got your
foot to the
floor to 35-40 mph levels as other cars go around you at the posted 50-55 mph
speed
limit, is not by any stretch of one's imagination, 'good performance', in fact
it's
the complete opposite.
> Over 20 yrs, even ni-cads are less costly than
> AGM's!!!!!
Agreed.
> .
> Sam, for you an early RX-7 with GC batts could
> give great range, performance from light weight and
> good aero.
The early RX7s were in the 2300 lb. range, as stock. Their unibody build design
is not up
to holding high weights in battery packs. A 1200 lb. pack of golf car batteries
stuffed in
an early RX7 turns what used to be a fun and nimble car, into an overweight
slow, poky
machine that handles horribly, brakes horribly, and will end up with body
damage. I know
from first hand experience. A local conversion I unfortunately had to try to
keep together
for an older person, had, count 'em, 25 Optimas stuffed in it. That's 1125 lbs.
of
batteries, 75 lbs. 'less' than a stack of 20 golf car batteries. With a 500 amp
controller
and a 144V pack of stiff AGMs (the 25th Optima served as the 12V supply), this
car ran
0-60 in what I'd estimate to be 18 seconds or so. Even with beefed up
suspension, it handled
like a pig, and braking was on the scary side of things! More importantly
though, cracks began
to appear in structural areas because of all that weight placed in areas it
wasn't meant
to be.
If you're going to do a 1200 lb. stack of golf car batteries, choose a small
but stout
pickup as the base vehicle. It's designed to carry weight, has the bigger
brakes to handle
hauling down that weight from road speeds, has the strength in body design to
hold that
weight, and will perform similar to the stock truck loaded with a 1200 lb.
payload.
> A 2 motor setup can cut the need for higher
> powered batts as they can start in series making twice
> the torque for the same amps. This with a Zilla would
> get you up the track quite quickly on GC's.
>
Agreed on the increased torque, agreed on the fantastic motor controller,
agreed on the
reduction of current needed from the batteries due to controller low motor rpm
amp
multiplication...totally in disagreement about getting you down the road, let
alone down
the track 'nicely'...just too much weight, and not enough available horsepower
to get the
job done!
I'm not anti-golf car batteries, that's so far from the truth, it makes me
laugh. I've
probably built more golf car powered EVs than most on this list, and I've been
involved
with said type conversions in numbers too large to list. For first time EVers,
you can't
can't beat the affordability, simplicity in charging and predictable results of
golf car
batteries. I think using a 1200 lb. stack of them in a stout import truck like
an
80s-early 90s Mazda, Nissan (Datsun), or Toyota, is the best platform to make
a fun,
reliable EV with a 50-75 mile range. The downside, is that it won't be a
performance
machine or even equal to most economy cars' performance. Passing other cars
will be
something you'll have to carefully consider and plan out in advance. It will,
however
pass every and all gas stations with ease.
See Ya......John Wayland
--- End Message ---
--- Begin Message ---
All this sounds a lot like the Subaru Brat I picked up a few years ago.
The guy and his son had installed a pulley (with bearing blocks) in the
rear driveshaft, and mounted an electric motor and some batteries in the
truck bed.
With the transmission in neutral you could drive pure electric, or you
could start the motor and drive with the ICE.
I bought it after the batteries were shot, and the relay controller was
dead. Never did get it working as a hybrid again. sigh. (Of course, all
that weight did overload the poor little thing, and the rear axles started
failing shortly after I got the car.)
At 08:01 AM 12/29/2004, Jeff Shanab wrote:
My previous idea of using the 4x4 transfer case has some real issues with
rpm, the poor eletric motor would have to operate at drivleline speed.
Here is a wilder idea
Remount the engine 1" to 4" forward to allow for chain or belt from a
smaller eletric motor pully to an adapter sandwhiched between flywheel and
clutch.. This contans a one way clutch so the ICE motor isn't forced to
spin. The make roller sprags capable of this, but I don't know the cost.
The eletric motor can then lie parallel to ICE in engine bay. both can use
transmission and the eletric motor can be chosen as one that can handle
regen, if the person wants a small pack.
You could even start the ICE while in motion then just step on the old
gas pedal to lock in the clutch
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream....
http://www.CasaDelGato.com
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--- Begin Message ---
Lets keep in mind that the AVDC motors 6.7,8 and 9 inchers have a series
paralel setup as stock. Each north and south pair are in paralel with each
other.
So.. Stock is 1/2 field weakened already.
So... look again closely into your AvDC and tell me what you see.....
from each stud to the next, is only two coil sets, one CW and the other CCW.
So.. Da Juice flows both ways.
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, December 28, 2004 11:36 AM
Subject: Re: Motors in series? Torque vs. power?
> >> I've noticed my 4 pole, series, ADC motor has the field poles in
> >> series and the armature poles in parallel... can we pull the same
> >> series/parallel trick on the armature of a single motor, similar
> >> to what is being discussed for a two motor drive?
>
> Joe Smalley wrote:
> > There are four brushes alternating positive and negative around the
> > commutator. All four quadrants of the armature are in parallel.
> > The best I can imagine would be to change the polarity of two field
> > poles to make it a two pole motor and then use only one pair of
> > opposing brushes.
>
> I don't think that would work very well. There are in effect 4 armature
> coils. They are wired in a square, with a brush at each corner. Going
> around the square, the brushes are + - + -. When powered, this structure
> generates 2 north and 2 south poles. Thus, the field has to provide a
> matching 2 north and 2 south poles.
>
> Off the top of my head, I think if you connected power to only the
> diagonal two + brushes (making one + and the other -), you'd have 4
> times the armature resistance. The poles on its surface would be N N S
> S. If you rewire the 4 field coils to produce the same poles (N N S S),
> it should run as a 2-pole motor, but with a badly designed pole shape
> (there would be a "hole" in the center of each N-N and S-S pole where
> the peak field strength should be), and with twice the normal winding
> resistance. So it would be a rather inefficient motor.
>
> But, you *could* wire the 4 field poles in parallel, series, or
> half-parallel, half series. The stock setup (all in series) provides the
> lowest speed per volt and highest torque per amp. Half-series and
> half-parallel is equivalent to 50% field weakening, and is faster per
> volt, and less torque per amp. All fields in parallel would be
> equivalent to 25% field weakening, even faster per volt and less torque
> per amp.
>
> It's usually easier to accomplish this with an external field weakening
> resistor (far fewer connections).
>
> But, there is a special case that is interesting. If you have two
> motors, you can wire their armatures in series/parallel; and
> independently wire their fields in series/parallel. Now your
> combinations are:
>
> armatures fields result (compared to a single motor)
> --------- ------ -----------------------------------
> parallel parallel stock rpm/volt, 2x torque/amp
> (100% field)
> parallel series less rpm/volt, 4x torque/amp
> (200% field)
> series series half rpm/volt, stock torque/amp
> (100% field weakening)
> series parallel more rpm/volt, half the torque/amp
> (50% field weakening)
>
> The parallel armatures, series fields case is interesting, because it
> provides even more torque per amp. It could be useful for drag racing or
> any time you need even more torque at low speed.
> --
> "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 ---
----- Original Message -----
From: "John Wayland" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, December 29, 2004 10:10 AM
Subject: Re: Range + Golf cart vs. AGM wars
> Hello to All,
>
> I'm responding to this thread once more, not to drown out others, or
impune them in any
> way. I realize there are newbies on this list looking for good advice
though, and I want
> them to hear the straight scoop on what they can and should expect from a
heavy, lower
> voltage golf car battery type EV conversion.
> Hi John an' All;
Been following your Battery thread, nodding in full agreement, as a
classic 1200 GC lead sled Rabbit driver. I get to 60 eventually, use a
calender, rather than a stopwatch ! I think the Acela train duz a better
than my 0-60<g>! I 'll do a 0 to 60 with the Acela when the conditions are
right, stay tuned, sports fans !28k voltage is fun! NO sag! Wheelslip is the
problem here!
A Led Sled is good training wheels. You want something BETTER, For sure,
a drive in the EV -1 shows the way. How deep are your pockets? I wanta dump
thre lead, go lighter!
Can we see some prices for say, Optimas, Orbitals, and howbout this new
Deca Dominater, that folks have mentioned, on here. Or the Thundersky
offerings. I think some Listers have stepped up to the plate here? Gees! We
NEED something better! The crappy range in cold weather you guyz didn't
mention with the GC's! HALF the range, 30 volt sag when it's zero out. Yes
,ya say, insulate the battery boxes, but they will boil away in our tropical
summers. Another trade off, for us guyz that have real winters. OK Rick sez"
Move here to Phoenix", I can't do those 100 plus degree SUMMERS, thanks.
Lived in Fla in my Citicar Daze, no thanks, hot, humid, buggy, rainy. Nope!
Old New England throw another log on the fire, here.type guy! Now if I could
get the godamn Tecumseh powered snowthrower to start! I WILL get the
Electrac together, soon!
I look at the battery thing as something to live with, like New England
winters, til something better is invented, better batteries. AGM, and that
stuff STILL suffer the same things GC's do, lousy winter performance, the
Pukert thing. Bill Dube? You got yur ears on? How's the Wabbit with the
Saft Nicads doing?Not affected by Denvers's cold winter?
Ah, but John has come up with some great comparisons with batteries.
Your Miliage may vary, A sedan like Blue Meanie is my next version, NOT
overweight, now just gotta sort out the battery thing$$$ I won't need a 50
plus mile commuter car, when I retire, and don't need to do my battery
killing trek.
Bottom line; Keep the battery dialog going for the newbees as well as
the rest of us.The great thing about the List, we can stay on top of what's
happening.
Seeya, at 1200lbs 120 volts, for now
Bob
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Chris Zach" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, December 29, 2004 4:45 AM
Subject: Re: The Amazing Little Hawkers.
> > Within reason, you can pretty much whack AGMs with any voltage and
> > current you want during the bulk phase. In fact, if you watch out for
excessive
> > heat, you can even pump in UNreasonable amounts of current - in the
> > hundreds of amps.
>
> I totally and completely agree with that. Really. One million percent.
> There's just one tiny problem:
>
> How do you know when an individual battery in a string has hit the end
> of the "bulk charge"?
Like DUHHHH!!
with Rudman Regs of course!!! Hooked back to the chargers. And in this case
also back to the control PC and software.
That's why I have been busting Butt to get Regs on the monster charger...
With 36,000 watts on hand... and over 200 amps of charger to make that
happen, The Regs are a rather important part of insane charge levels Backed
with
safety control gear to keep the lead from getting sprayed about.
>
> That's the unknown, and I think that's where the problem is. If you have
> a pack of 25 batteries, and battery number 18 in there is a trifle bit
> different from it's neighbors, then it may hit the end of bulk charge a
> bit before it's neighbors. Since that's one battery out of 25, you might
> not see that it went over 14.7 while it's friends are all at 14.0 if the
> only thing you count on for telemetry is battery voltage.
>
Believe ME, it's not just one battery that gets slammed it's about 4, and
they can be different batteries at different times of the cycle.
> Does the above make any sort of sense?
>
complete... and as noted in REAL charge cycles..
> > It's during that last 20% of the charge that you need be concerned - and
with
> > CURRENT more than voltage. Once a given cell is above the gassing
> > voltage, the more current that you give it, the more it gasses. If the
gassing
> > is slow enough that the recombination reaction can keep up with it, all
is
> > well.
The trick is ti never let them gass.
And at over 40 amps of charge current it's that last %50 of the cycle. As
you add more amps the point where any battery hits 14.8 gets sooner in the
cycle.
With infinte amps.... the voltage regualtion point will be almost instant.
Then you have the whole cycle in tapering back amps to maintain the given
pack voltage, interupted only by single batteries that can't take the full
amps. Or said another way, The pack will have a voltage controlled taper
slope, that the charger will follow, and if a single Battery, protected with
a Reg can't keep that battery regulated to 14.8, Then the taper back slope
will get steeper to allow the reg to bring it's battery back into line. When
we did the 80 amps(20Kw) cycle we got 9 amphours back in before we hit the
main pack voltage limit of 191 volts, then seconds later the Regs went wild,
and the amps dropped. The total amp hours returned was just under 25.
We need to publish a screen shot of this.... It's rather impressive.. and
takes a lot less typing on my part.
I want to show a charge plot of basicly no Bulk phase, all exceptance phase,
because we can drive the battery stack to it's voltage limits at will.
>
> Right. Which is why I think one can charge at 2.5amps using the dopey
> Dolphin "safely". The recombiners can keep up with this apparently, but
> they can't keep up with 20 amps. I think that was the Dolphin idea, and
> in theory it should work great.
What you need to do is dump in as many amps as you can until the voltage
comes up, Then drop back to the 2.5 amps. We find that keeping the 20 amps
on while in taper back is where the Damage occurs. Once the pack hits full
voltage THEN you need regs. Once the total amps drops below the recombiner
max limits then Regs are also not needed. In theory... In practice Keep the
regs on since the combiners still can't keep 2 amps at 16 volts from
gassing...
>
> Also why I ask about lowering the voltage setpoint from switching from
> bulk charge to finish charge rate. That's the only window I have in my
> pack at the moment, and if I drop down from 362.50 to 350 say for this I
> reduce the chance of "clipping" a battery. By lowering the bulk current
> at the start, I also limit the damage somewhat if a battery was really
> weird. Though the more I think about it, if one battery goes above 14.7
> while the pack itself is at 14.0 average (350) then maybe it's time to
> drop the pack anyway.
>
You are correct here, dropping the pack voltage can almost eliminate the
Reg's abuse....Like if you are carfull, The regs never go active....But this
takes time, and lots of hand meter checking.
On a fresh pack you have the same issues, until you get the first
equalization strokes on the pack. So... driving the pack towards
equalization...new or used takes time and or really hot regs and a Lot of
charger feedback.
I find that a old pack can be brought back... and when you can't with
reasonable efforts, then you have to find the weak and remove it. This also
goes for a new pack and a Blem battery.
> Except for this "Hawkers *REQUIRE* that you charge at high rates during
> bulk" thing. Why? To what level? Can I charge at high rates for 5
> minutes of the charge to "blow off the electrons" or whatnot then crawl
> back into my lower-current pit of comfort? How about 30 seconds of
> charge at 6C (150a regen, assuming the pack is unbalanced 99% one
> string, 1% the other)?
What???. As I said earlier... you don't need the high rate. On being
corrected, is seams that a C/3 rate is all that is recomended. The Why, has
not been stated, it's just that the cycle life is a bit greater if you do
charge them a bit faster. Do the Bulk at 20 amps and the taper at 2.5.
Unbalenced string???
>
> > Again you have missed a crucial point here. No, it is NOT around 0.5
amps
> > per string. You can't be sure that one amp from your charger is
dividing
> > equally between the parallel strings. It's quite possible that 0.99
amps is
> > flowing through one string, and 0.01 amps through the other. The
charger
> > should limit the equalization current to no more than the value that's
> > acceptable for ONE string.
How are you going to do this??
>
> *nod* I was assuming that 1 amp (actually .8a IIRC) is safe for a 26ah
> battery so that it won't gas. I can test this easily enough; take a
> Hawker out to the woodshed, remove the top (so the cell nipples will pop
> off if it gasses) and charge away using my 1 amp constant
> voltage/current bench power supply. If I can make the nipples pop, I'm
> gassing.
>
Yup and .8 will do that! IF you have(had) a good battery, and lots of time.
> > Two packs, going on three. These are expensive lessons, aren't they?
Been
> > there, done that, still learning. IMO, it sure would be nice if we
could just
> > lease and maintain battery boxes with chargers and BMSes built into
them.
> > That way we could pay somebody (presumably knowledgable) to ensure that
> > the charge algorithms were correct, that the battery was always meeting
its
> > minimum specs, and that it was properly fixed if/when it wasn't.
OK.... 10K$ a pack, and a monthly service agreement of $250, You will need
to have the Ev attached to the charger at all times you are not using it.
And I need a IP address to do daily status checks.
You want turn Key? total hands off, that just means that someody else has to
do it for you. And that costs.
>
> Yes, they are expensive. And I hope this pack lasts longer. Even so, 6k
> miles is not the end of the world; I've read about people flattening US
> battery floodeds in 8k. And it's an AGM pack, so it makes for a fast
> little car. I'd just like to understand *why* the pack blows up
ultimately.
>
> Chris
>
I can write papers and desertions on why.
I have a business that is attempting to solve most of these issues....with
hardware and public knowledge on what I find.
Business has been good.
don't feel alone, alot of us want to keep our EVs running for longer and
have cheaper up keep on our packs.
Cheap is flooded and a watering schedule... Easy is a AGM and a set of Regs,
and a darn good charger. But...it's not cheap.
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
>> Say you have 1200 lbs of golf cart batteries. At 65 lbs each,
>> that's about 18 65 lbs batteries; a 108v pack. Your peak power
>> is about 108v x 500a = 54kw, or 54 HP. You can draw this for
>> 5-10 seconds without harm...
>>
>> If the car has a motor/controller/transmission combination that
>> lets you stay reasonably close to peak power as you accellerate,
>> such an EV is going to do a lot better than 0-60 mph in 20 seconds.
>> Bob McKee's Sundancer had this 50% golf cart battery setup, and
>> did 0-60 mph in 12 sec.
John Wayland wrote:
> Lee, I think you've got some figures wrong. A 2400 lb. vehicle
> with just 54 hp, in no way, will it hit 0-60 in 12 seconds! ...
> The Datsun 1200 sedan only weighed 1587 lbs. and with 15 more
> horses under the hood, 69 hp, it ran 0-60 in 14.5 seconds. How
> does a car weighing 1000 more pounds, with 15 less hp get to
> 60 mph nearly 3 seconds quicker?
I'm travelling, and depending on my memory, so you could be right. I
don't have an easy way to calculate how fast you could do 0-60 mph on 54
kw. (Can anyone help?)
As I recall, the first Sundancers had a stock series DC motor (perhaps
80% efficient, contactor controller (nearly 100%), and 2-speed rear axle
(maybe 95%). 0-60 mph was something like 20 sec. He attributed this to
the motor not actually running at its peak HP most of the time.
So, he installed an SCR PWM controller; range and top speed barely
changed (these old controllers were around 95-98% efficient), and
accelleration improved a bit. But the battery current-vs-time profile as
the car accellerated still had a sharp peak at the two optimal points,
in each of the two gears as the controller just came out of current
limit. The motor only saw peak current and full pack voltage at this one
point.
So, he used a pair of variable-speed belts, one driving each rear wheel
from each end of the motor. This lowered drive train efficiency (maybe
90%), but continuously varied the ratio during accelleration to keep the
battery current near its full 500a throughout. This is the version that
accellerated the fastest (12 sec as I recall).
My guess is that your Datsun 1200 had 69 HP *peak*, which it only
achieved for brief moments in each gear. During a 0-60 mph accelleration
run, there were times when the HP was less (when engine rpm was well
away from its peak), and even zero HP (during shifts). I don't know what
the average HP was during the run, but it could easily have been only
30-40 HP.
So... if a vehicle only has 54kw, but it can produce this 54kw
continuously as the vehicle accellerates, how fast can a 2400 lbs
vehicle accellerate?
> Another thing to consider, is that the original subject of
> discussion, was using golf car batteries in a conversion, not
> a ground-up concept car like the flimsy, foam board rolling
> science project creation called the Sundancer.
I agree that it will be difficult to carry 50% battery weight in any
vehicle not built from scratch or heavily modified.
But, the Sundancers were hardly "flimsy, foam board rolling science
projects". I've seen them, visited the designer, and tried hard to buy
one. They are *not* conversions; they are the best example I know of for
what happens if you try to build a high-performance EV with inexpensive
components. They were professionally designed and built, very strong,
and had exceptional handling. They were, after all, built by one of the
foremost race car designers of the time.
>> I think there is hope to improve the 0-60 mph times with some kind
>> of booster pack to provide higher amounts of power for 10-15 sec.
> True, but this only points out the limitations of the golf car
> batteries, and would require even more weight to be piled in an
> already over-weighted EV.
No; what I'm saying is that you decide what range you need, and that
defines how much battery weight you need. Rather than all-floodeds, or
all-AGMs, you can compromise and use some of each. The total pack weight
is the same. Sure; you won't achieve the ultimate in performance. But
you won't pay nearly as much for the pack, either. To many people,
economics play a big factor.
The beauty of this is that you can pull out the floodeds if you want to
go racing. Now you've still got your peak power, but much less weight.
>> Braking is of course unrelated to batteries.
> Yes, there are heavy production cars that weigh as much as the
> 3400-3500 lb. golf car battery conversion, but to get them to stop
> requires fat tires with lots of grip, something pretty much the
> opposite of what an EV needs to get the lowest rolling resistance
> possible.
Here again, life is all about compromises. Drag slicks provide the best
traction, but are worthless in rain or snow. Ultra-efficient tires win
economy races, but ride harshly. Long-life tires are noisy and. To get
excellent handling and braking, the tires have high rolling resistance
and wear out quickly.
We can't have separate sets of tires for every day of the week. So we
all pick a compromise tire that is "good enough" at all the things we
judge important.
> Choose your batteries with your eyes wide open. If 60's era
> VW bug type performance levels are OK with you, then a heavy
> conversion with 120V worth of flooded type 6V golf car batteries
> are the way to go. For the least amount of dollars out of your
> pocket, you'll get long cycle life and long range per charge.
>
> If, however, you want your EV to perform well, you might consider
> other types of batteries. Flooded type 6v golf car batteries
> will not give good range or good cycle life if forced to make
> your EV conversion act like a regular gas car in terms of
> performance, and in fact, will not last as long or give as good
> range as the more aggressive and more expensive AGM type high
> performance EV batteries.
Agreed!
--
"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 ---
