EV Digest 6948
Topics covered in this issue include:
1) EVgrin - RAVolt takes first EV trip
by [EMAIL PROTECTED]
2) Re: VOLTS vs AMPS
by MIKE WILLMON <[EMAIL PROTECTED]>
3) Re: 55 MPH Part III
by "Phil Marino" <[EMAIL PROTECTED]>
4) Re: Over-volted ADC: Warranty issue
by "Chuck Hursch" <[EMAIL PROTECTED]>
5) Re: firefly batteries?
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
6) Re: Selling or buying an EV
by "Tom Shay" <[EMAIL PROTECTED]>
7) Re: 55 MPH Part II
by Eric Poulsen <[EMAIL PROTECTED]>
8) Re: vroombox and EV ?
by Eric Poulsen <[EMAIL PROTECTED]>
9) Re: firefly batteries?
by "Zeke Yewdall" <[EMAIL PROTECTED]>
10) Re: Selling or buying an EV
by "John G. Lussmyer" <[EMAIL PROTECTED]>
11) Re: Selling or buying an EV
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
12) Re: Cheap "balancer" for A123 pack
by =?ISO-8859-1?Q?Jukka_J=E4rvinen?= <[EMAIL PROTECTED]>
13) Controler
by "Phelps" <[EMAIL PROTECTED]>
14) Re: 55 MPH Part III
by Victor Tikhonov <[EMAIL PROTECTED]>
15) Re: Controler
by "Zeke Yewdall" <[EMAIL PROTECTED]>
16) how to control my separately excited DC motor....
by "Zeke Yewdall" <[EMAIL PROTECTED]>
17) Re: Controler
by "Phelps" <[EMAIL PROTECTED]>
18) RE: Cheap "balancer" for A123 pack
by "Roger Stockton" <[EMAIL PROTECTED]>
19) Re: Cheap "balancer" for A123 pack
by =?ISO-8859-1?Q?Jukka_J=E4rvinen?= <[EMAIL PROTECTED]>
20) Re: Controler
by "Roland Wiench" <[EMAIL PROTECTED]>
21) Re: Controler
by "Phelps" <[EMAIL PROTECTED]>
22) Re: FW: Regen with Sevcon and Etek
by [EMAIL PROTECTED]
--- Begin Message ---
All,
I know the list loves good news: the RAVolt made her maiden voyage
over the weekend!
YouTube: http://www.youtube.com/watch?v=hUv3wZQTcQE
Rob H
RAVolt.com & EValbum 995
--- End Message ---
--- Begin Message ---
You (and Dan) are correct. What I meant to state is that the "charge" flows
near the speed of light and thus carries to the conclusion that Amps (or
electrical current) is a measure of the amount of "charge" that flows past a
certain point in 1 second. A coulomb of charge being equal to that of 6.023^23
electrons. I didn't mean to get into the tricky details of electron drift,
which as you say can be on the order of mm/sec.
The analogy that works for me is that of the little contraption with the steel
balls suspended in a straight line from some string. Swing 1 ball out and let
it go. It contacts the mass of other balls and (almost) instantly the Energy
is transfered to the ball on the opposite end and it flies up into the air.
Now the number of balls (analogy for the electrons) that move from one end of
the line to the other is small (zero in this case). But the energy contained
in the original ball has moved almost instantaneously.
Without getting too technical but trying to remain technically correct, I meant
to state that the propagation velocity of the charges remain nearly the same,
at a high percentage of the speed of light, in a constant medium.
Thanks for the correction.
Mike,
Anchorage, Ak.
----- Original Message -----
From: Victor Tikhonov <[EMAIL PROTECTED]>
Date: Monday, June 25, 2007 11:01 am
Subject: Re: VOLTS vs AMPS
To: ev@listproc.sjsu.edu
> So you know, the speed at which electrons are "moving" in the
> conductoris a few millimeters per second.
>
> What you probably refer to is the time electric (or electromagnetic
> if AC) field propagation speed which makes electrons start moving -
> that is at light speed. Therefore you see light few miles away goes on
> as soon as you flip remote switch despite actual electrons moving
> few mm/sec. Not very accurate but obvious analogy is moving
> water in a pipe - assuming water is not compressible (which is
> almost he case), it can start flowing out of a mile long pipe
> as soon as you start pumping it in in the other end, though the
> rate of the water flow itself may be few inches per sec.
>
> Victor
>
> p.s. Without digging too deep, electrons themselves are not moving
> anywhere - their charge get carried from one to another and charge
> has no mass. If electrons were to move, the mass of conductor would
> have measurable weight change (you can cram in more than you take out
> but no one was able to detect any weight difference between "charged"
> and neutral conductor), not to mention that material itself would
> become different - copper with "lost" valence electrons is no longer
> really a copper...
>
>
>
> Mike Willmon wrote:
> > To be technically correct electrons flow the same speed in a
> particular medium, which is some relatively high percentage of the
> > speed of light. Amps (or electrical current) is a measure of the
> amount of electrons that flow past a certain point in 1 second.
> > More amps is more electrons per second
> >
> >> Joseph Tahbaz wrote:
> >>
> >> What are amps? Well, amps are how quickly the electricity moves.
> More>> amps, which means the electricity is moving faster, which
> means more
> >> watts (power)
> >>
> >>
> >
> >
> >
>
>
--- End Message ---
--- Begin Message ---
From: Victor Tikhonov <[EMAIL PROTECTED]>
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Re: 55 MPH Part III
Date: Mon, 25 Jun 2007 12:14:24 -0700
Phil Marino wrote:
Although this idea is sound, there are no commonly used units that make
the above equation true.
It might be clearer to say the HP = C x torque x RPM, where C = 5252
HP/ft-lb/RPM, and torque is in ft-lb, This is the number you give a bit
later on. I'll show where that number comes from.
Power = Torque * rotation speed, period.
I agree, Victor. But that's not what I had a problem with. The equation I
didn't like was:
HP = torque x RPM.
If it's written that way, someone will certainly plug in some value for
torque, and RPM, and expect to get a number out that equals the power
(expressed in HP). They would get the wrong answer.
As to metric units, you're right. The world of engineering would be an
easier place if everyone used metric units all the time. But, us old dogs
don't learn that quickly.
And, in the US, it's easier to find a 1/4-20 screw than a 6 mm one. And,
you can't go into Home Depot and find a metric measuring tape.
Phil Marino
By the way, even in metric units, expressing power in terms of torque and
rotational velocity is not obvious and simple.
A watt does not equal a newton-meter of torque times a revolution per
second.
Instead, a watt equals a newton-meter of torque times a radian per second.
And, who uses radians?
"C" is something you add when use different that metric units - it is for
your convenience, but not in definition of power.
It would be oh so much easier if everyone would just use metric units,
but we've gone through this before and as with everything, people stick
with what is more convenient to them.
Wonder if when ft*lb is mentioned why is it not also specified
if it's British lb or US lb. So much for the "convenient" system.
Victor
_________________________________________________________________
PC Magazines 2007 editors choice for best Web mailaward-winning Windows
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--- End Message ---
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'Nother thing you might check is that the brush leads are not
pinched between the bell-housing and the frame of the motor (or
was it the edge of one of the screws in the brush assembly? - now
I'm getting fuzzy...). Anyways, back in 2005 when I was
replacing the battery pack, I had plenty of daylight and space to
check over the 8" ADC in my mod VoltsRabbit conversion. My blood
pressure went up several clicks as I came to terms with the
significance of the wire with the copper snot hanging off of it
at the end of my motor in the brush area. I had the car down at
Redwood City at a fellow EV'ers place, and within an hour or two
of having an extensive and rather frustrating discussion with my
EV friend, I decided to place a "Please Help!" call down to Ot in
Palo Alto (I watched Ot disassemble/re-assemble an 8" ADC at the
Phoenix raceway in the mid '90s, and was rather impressed.).
Otmar was very helpful in saving me from this fix, dropping
everything in the evening and bringing a brush wire rigging from
one of his motors (albeit a 9") up to Redwood City and helping me
install it. Ot and I both came to the same conclusion, that one
of the brush leads had slipped down, or had always been there,
back in between the bellhousing and motor frame / brush assembly
screw, pinching and wearing through the insulation, causing a
short and melting the wire. I don't know how long the motor was
running on less than the full complement of brushes, but I did
check the motor during the previous battery swap in 2001 and
don't recall seeing any problems. Fortunately, it didn't damage
the controller. So the moral of the story is to perhaps check
where those brush leads are going, and if they appear like they
might get pinched, do something about it. They can and do get
messed up.
8.5" motor? A 9" rigging makes for a full house, although it
does not seem to have presented any problems in things getting
warm (lack of airflow). I haven't checked in there since 2005,
but everything runs...
Chuck
----- Original Message -----
From: "Jim Husted" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, June 13, 2007 9:17 PM
Subject: Re: Over-volted ADC: Warranty issue
> Plenty of examples of people using them at higher
> voltages. Keep your RPM's limited to 5000 an you'll
> be fine (unless you get a lemon to begin with, lol)
>
> One thing to note that I've found. On new motors, ADC
> uses (at least the few I've seen) a flat brush and it
> is not seated. This is why all the old timers ran
> their motors in. I doubted all their seating in talk
> of flat brushes as I had never seen a non-pre-seated
> brush before. When I order replacement brushes they
> come pre-seated or curved to basic commutator curve.
> Kind of fun to find the answer to why we're all
> looking at each other like we're crazy, and don't
> think the other knowwhat the heck their talking about,
> truth is there are two different brushes one for new
> motors and one for resale.
>
> Next, make sure it's set so the brush timing is
> correct for your rotation and it should be timed for a
> CCDE rotation when received.
>
> One last thing, you might want to test all the brush
> and lead screw connections (just don't stab the comm
> with the screwdriver). I found a lead connection on
> one of Lawless' ADC9's and it was two full turns loose
> which would have caused a warranty at even lower
> voltages but could still be used against you if this
> were to happen.
>
> To be really thorough after blocking the motor bench
> test it under "12 volts" and run it to make sure she
> arrived safely with no shipping damage. Issues are
> not the norm, ADC makes a good motor, just some things
> to be aware of so to speak.
>
> If nothing else tame yourself from John Wayland like
> "desires" to pound down the amp peddle to see what
> she'll do, until you've put some miles on it and
> developed some comm film as well as seating in the
> brushes.
>
> Anyway just thought I'd put my two cents in.
> Hope this helps
> Jim Husted
> Hi-Torque Electric
>
>
>
>
>
_________________________________________________________________
___________________
> Be a better Globetrotter. Get better travel answers from
someone who knows. Yahoo! Answers - Check it out.
> http://answers.yahoo.com/dir/?link=list&sid=396545469
>
--- End Message ---
--- Begin Message ---
If what they say is true there won't be any difference between them and
regular lead batteries except capacity, durability & reliability. I suspect
they won't even need regulators. Lawrence Rhodes....
----- Original Message -----
From: "Zeke Yewdall" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Sunday, June 24, 2007 8:22 PM
Subject: firefly batteries?
> Wondering if anyone has any thoughts on these? I sort of have an in
> with the company to test some in my EV (probably about 5 or 10%
> probability, but that's better than no contacts)... but as of yet all
> I've seen is hype, not specs. BMS required? Discharge rate? cycles?
> Thermal management? Not even sure if they really exist yet.... I
> supposed I could ask my contact there, but I figured someone on this
> list might have already researched them more than I have.
>
> Z
>
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--- Begin Message ---
I'd love to see a big guy like Bruce stuffed into a Sparrow. <big grin>
Sparrows have numerous and serious problems. Nobody should buy
one without seriously investigating and deciding that the problems are
things one is willing and able to cope with.
----- Original Message -----
From: "John G. Lussmyer" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, June 25, 2007 12:14 PM
Subject: Re: Selling or buying an EV
At 09:21 AM 6/25/2007, bruce parmenter wrote:
...
Because the used EV market is so bone dry, my EV withdrawals
has me looking at what EVs 'are' available. Besides used GEM
nEVs, and new Zap's Xebra 40mph EVs, there really isn't any
EVs that are in the $15k range (sorry, no longer work for hp
which would give me my former income to afford a Tesla EV).
Used Sparrows are generally available for that or less.
(Yahoo SparrowEV group)
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream.... http://www.CasaDelGato.com
--- End Message ---
--- Begin Message ---
Rob,
This question is roughly analogous to your Amps VS Volts question. V =
volts, A = amps, T = torque, S = speed, W = Watts, HP = Horsepower.
Both Watts and HP are measurements of power, and there is a direct
relationship. You can convert HP to Watts and vice-versa.
V * A = W (power)
T * S = HP (power)
Some correlations:
If any of the values is zero, then the power is zero. 1000A at 0V =
0W. 200ft-lbs torque at 0 RPM = 0 HP.
What this means is that when your wheels aren't moving, then the _only_
thing that matters is the torque. Once your wheels start to move, the
total HP being applied to the wheels is Torque * Speed. You can
calculate the needed torque (and thus HP) to accelerate from a given
speed to another speed within a certain amount of time.
Having said that, bear in mind that the HP ratings of electric motors is
nearly non-comparable to an ICE (internal combustion engine). HP
ratings for electrics are for continuous horsepower, while gas engine HP
is rated at peak HP at a particular RPM. An electric motor can often
provide 10X the rated HP for brief periods of time.
Rob Hogenmiller wrote:
From what I've been reading it takes about 60 ft/lbs of torque to
maintain
an average vehicle at 55mph.
Or around 5-10HP.
I've noticed that there inexpensive motors that produce the HP ratings
no problem, but from what I'm reading the won't produce the torque
requirements, for example this motor meets the HP rating but not the
torque, http://www.electricmotorsport.com/PARTS/Perm.htm
What other motors might I be eyeballing that could maintain 55mph?
( I will have the capability to use two motors, but prefer not too if
not necessary.)
I have a near unlimited run to reach 55mph so it's not important that
I have a motor that help me reach 55mph quickly (I'll be using a gas
engine to propel me to speed), I'm hoping to find one the will help me
maintain that speed, to do some testing of theories on a budget.
God bless
--- End Message ---
--- Begin Message ---
Hear Hear!
Garret Maki wrote:
I think it is a terrible idea. Attentive pedestrians are the answer, not noise
pollution.
-Garret
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Florian Schmidt
Sent: Sunday, June 24, 2007 3:17 PM
To: ev@listproc.sjsu.edu
Subject: vroombox and EV ?
Thinking about the pedestrians that don´t hear an EV coming, i was wondering if
it´s possible to install the vroombox in an EV.
What do you think ?
http://www.vroombox.com/vroombox/
--- End Message ---
--- Begin Message ---
http://www.electrifyingtimes.com/firefly_energy.html
There is this.... doesn't sound really promising as far as
availability. My friend is trying to get more info from his uncle,
who's the one in firefly.
Z
On 6/25/07, Lawrence Rhodes <[EMAIL PROTECTED]> wrote:
If what they say is true there won't be any difference between them and
regular lead batteries except capacity, durability & reliability. I suspect
they won't even need regulators. Lawrence Rhodes....
----- Original Message -----
From: "Zeke Yewdall" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Sunday, June 24, 2007 8:22 PM
Subject: firefly batteries?
> Wondering if anyone has any thoughts on these? I sort of have an in
> with the company to test some in my EV (probably about 5 or 10%
> probability, but that's better than no contacts)... but as of yet all
> I've seen is hype, not specs. BMS required? Discharge rate? cycles?
> Thermal management? Not even sure if they really exist yet.... I
> supposed I could ask my contact there, but I figured someone on this
> list might have already researched them more than I have.
>
> Z
>
--- End Message ---
--- Begin Message ---
At 02:13 PM 6/25/2007, Tom Shay wrote:
I'd love to see a big guy like Bruce stuffed into a Sparrow. <big grin>
You should see me get in/out of mine. 6' tall, 260lbs, beard. With
a Lilac Sparrow. (purple/pink color)
--
John G. Lussmyer mailto:[EMAIL PROTECTED]
Dragons soar and Tigers prowl while I dream....
http://www.CasaDelGato.com
--- End Message ---
--- Begin Message ---
Until the vehicle is legally transferred, the original owner
is subject to whatever dumb things the 'new' owner does. I
would like to avoid that situation.
No worries here Bruce. Just fill out the form that is with the pink slip.
You fill out the new owners name and address, your name and address & return
it to DMV. If the person refuses to fill out the form you do it to the best
of your ability. Date & sign. You now are legally divorced from the
vehicle & liability. Lawrence Rhods........
--- End Message ---
--- Begin Message ---
Well.. I'm not suggesting to forgive TS for the whole screw up. Why
should you ? I'm telling what I have a chance to be a part of. Excellent
battery technology which perhaps will help EVs to be more popular. Is
there something wrong about that ?
To bring the technology up to western standards (yes, customer service
also) there's a lot to be done. But without the bond with the source of
the technology it's just sales rep BS after all. So I wanted to get
involved. But just to clarify. I do NOT own TS. Okey ?
Again. I had nothing to do with the old-stock-sales stuff that took over
here. I saw what happened and try to help now if I can.
TS has potential to blow the price off the Lions. Is there anything
wrong about that either ? Heck.. I've been waiting this to happen longer
than I have had a drivers licence.. I'm driving Lithium every day!
What ever the situation is.... the fact is that with very high
propability these batteries will not be sold in US anyway by TS. I think
there are already four factories starting to produce the tech around the
globe and other four trying to copy it (mainly in China). Different
packaging and outlook. So how you can tell what you're buying ?
Don, for the last line in your mail please define "balance".
Will the cells all die during the same cycle ? Will the cells be in
similar enough (0.01V) voltage during all SOC and loads and ambient
temps ? Do they achieve 0 and 100 SOC simultanously ?
( Getting back to topic ? :)
-Jukka
[EMAIL PROTECTED] kirjoitti:
Hello Jukka
All these claims below sound great but unless you take care of the prior
buyers of TS I will not be considering them. I would want to see real world
results with users here. I just ordered two motors from Victor and will be
reviewing my options on batteries.
The prior buyers were sold bad product and that has not been addressed.
Your company choose to keep the name and as far as I am concerned there is a
price for doing that. In one of your emails you stated how long must one
live with the past of a different company same name. To discourage this type of
customer service most people here and myself will say forever.
On the subject line I hear A123 batteries keep in balance very well.
Don Blazer
In a message dated 6/24/2007 12:11:33 PM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
Balancing only during charging will get the job half way done. With
shunting you'll accumulate quite bad well-to-wheel efficiency. Also the
charging time will be longer.
During discharge balancing is quite useful since you'll get the most of
range out too. And not stressing the weakest link the most. Also the
discharging can be weary process.
With Lions you'll get the range and at least in my drivings it takes
several hours to deplete the batteries. So power is not the issue with
balancing. You have time for the compensation procedures. Also
pre-emptive balancing methods are essential.
Ok. Say you wish the pack to last 50 000 miles. You'll get away with 200
mile range and 250 cycles. No balancing required. Some tape, bubble gum
and protection circuits will do the job.
So how about if the 3000 cycles could be achieved with the best BMS ever
made? That's with 70% average DOD about 400 000 miles. Say you invest
the 30 000 on the pack with BMS and charger. That's 0,075 USD for a mile !
(20 kWh/100 km assumed as average here)
-Jukka
Tony Hwang kirjoitti:
Yes that would be better to move charge around instead of shunting, but
there's no way to make an active charge shuttling balancer for "cheap", at
least not that I know of.
- Tony
----- Original Message ----
From: "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu
Sent: Thursday, June 21, 2007 5:39:45 AM
Subject: RE: Cheap "balancer" for A123 pack
Please educate me if I am wrong but I would think that if you want to
balance your batteries you wouldn't want to drain some down to match the
others but charge the low ones to match the others. Using shunt
regulators will waste valuable charging current won't it? I think Lee
Hart makes a battery balancer that takes the current and shunts it
AROUND the battery but does not run it through a resistor.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Marcin Ciosek
Sent: Thursday, June 21, 2007 5:12
To: ev@listproc.sjsu.edu
Subject: Re: Cheap "balancer" for A123 pack
Tony,
recently I bough 1900 LiFP cells (not from A123 but it doesn't matter)
and the voltage difference between highest and lowest value was 7mV !!
Assuming you will start from similar point you balancer will do the
trick as long as zener diodes won't differ too much (usually tolerance
of of shunt voltage is 5%). That's my opinion. I would add a protection
circuit preventing cells from deep discharge.
If you don't need fancy BMS that would cost (for you configuration) 400E
this will work fine.
Marcin
************************************** See what's free at http://www.aol.com.
--- End Message ---
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Just to keep it all straight.. When I wrote the short message about (making
it.).Am lost everybody here assumed that I was thinking about making a
electronic controlled controller....
Nope never said that and never wanted to do do that..
I was just thinking about a mechanically driven switch.. Not as nice as
what you are all use to.. Probably noisyer if it could be done ..
But if it could be done.. It would be cheaper..
Building a fancy mechanically switch .. Is that so hard .. Maybe .. Maybe
not.
I don't know but I sure do Have the thought.
Mitchell
--- End Message ---
--- Begin Message ---
Phil Marino wrote:
Power = Torque * rotation speed, period.
I agree, Victor. But that's not what I had a problem with. The equation
I didn't like was:
HP = torque x RPM.
If it's written that way, someone will certainly plug in some value for
torque, and RPM, and expect to get a number out that equals the power
(expressed in HP). They would get the wrong answer.
Correct, they would. RPM is what automotive gearheads are use to, but
in formula it is per second, not per minute, and also rad (2*pi of
them), not revolutions (360 degrees).
As to metric units, you're right. The world of engineering would be an
easier place if everyone used metric units all the time. But, us old
dogs don't learn that quickly.
You don't have to, though it would only be to your advantage.
I have no problem with that!
And, in the US, it's easier to find a 1/4-20 screw than a 6 mm one.
And, you can't go into Home Depot and find a metric measuring tape.
Not as easily found, I agree. But I only have metric tools in my shop,
Only work on Euro or Japanese cars and have no problem with that either.
Everything is familiar and easy. 12mm is bigger than 10mm, blindly obvious.
If I see 3/8 and 19/64, I have to think (or calculate) which one is
bigger :-) But that's me.
Phil Marino
By the way, even in metric units, expressing power in terms of torque
and rotational velocity is not obvious and simple.
Why? You multiply only 2 numbers to get 3rd one. What can be simpler.
Granted, you got to use right units.
A watt does not equal a newton-meter of torque times a revolution per
second.
Instead, a watt equals a newton-meter of torque times a radian per
second. And, who uses radians?
Everyone who calculates things in mechanical motion. C'mon. It's like
asking who uses pi :-)
Victor
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So..... I got my motor today -- haven't picked it up from the
warehouse yet, but I'm going to stop by tonight and get it. It's a
13" GE separately excited motor -- 1000rpm base speed at 96 volts.
Supposedly about 21HP continuous rating at 96 volts. Been used on a
couple of EV's before, since 1979, but supposedly only has 5,000 total
miles on it.
Now... I've looked for a suitable controller for it, and the largest
ones for separately excited motors seem to be around 48 volts and
600amps, or about 96 volts and 400 amps. I was thinking of running it
more like 120 or 144 volts (which the previous owner did run in an
EV), and more like 500 A or so (that depends alot on how much the
batteries will handle, I guess). He said that it would pull 600A at
144 volts if the batteries could handle it.
The previous owner just used field control I believe -- turn main
contactor on and the motor starts turning. Then you use the clutch,
just like in a regular ICE car, and the accelerator decreases the
field current to increase the speed. So, it occurs to me that I could
do the same (I'm keeping the clutch). But, I understand that you can
get a bit better performance if you also do armature control... Could
I use a controller such as for a series DC motor for the armature,
then a smaller controller for the field, with reverse control (so it
first increases the armature voltage and then decreases the field
voltage as the accelerator is pressed further down) And, how would
this react with regards to regen? (the whole reason I got this motor
instead of a 9" ADC) My understanding with regards to regen (driving
an Electrek which has a very similar motor with field control), is
that if you adjust the field currrent to the point where the base rpm
of the motor would be lower than the actual rpm, it will drive current
backwards into the battery to try to slow down. If the base rpm of
the motor is higher than the actual rpm, it will pull current from the
battery to try to speed up. But how would this work if I've got a
conventional chopper controller controlling the armature? Big bypass
diodes?
Initially, I might just set it up with field control only, but just
wondering what the options are for a more advanced system --
preferrably one that I can buy and not build myself (I have built
power control circuits before -- and blown up a bit of silicon -- I'd
rather just have a controller that works, than one that I have to
fiddle around with it)
Z
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--- Begin Message ---
From: [EMAIL PROTECTED]
Message-ID: <[EMAIL PROTECTED]>
Date: Mon, 25 Jun 2007 18:38:48 EDT
Subject: Re: FW: Regen with Sevcon and Etek
To: ev@listproc.sjsu.edu
MIME-Version: 1.0
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The Sevcon Millipak is a very smart controller. It is basically made for
fork truck and Walkie operation which means it has features you'll never use.
It
is not really set up to be a electric vehicle controller but with all of the
features it can work very well as one.
Sevcon Millipak braking levels are set using personalities 1.01, 1.02 and
1.03. each is stated in %.
1.01 is direction braking, it is activated by going from forward to reverse.
1.02 is Neutral braking level, it is activated by going to drive to neutral.
1.03 Footbrake braking, for use if you have a footbrake configured.
Choose 100% for maximum braking or lower for less braking.
There are also finish levels you can set (1.05) and start voltage levels
(1.04) I'm not entirely clear on these but my finish voltage is at max 255
which
will leave the regen braking on as long as possible.
There are other controls at 11.1, and 11.11 which can be set up when using a
pot for a footbrake.
I am using the neutral braking option. It is easy to set up and gives good
braking performance. I have it connected to the back footbrake pedal by
microswitch. I wish I could use the footbrake option with pot so that I could
get
variable regen but I haven't figured that out yet.
Because I have a 4 speed on my bike I can always get good regen. I see my
ammeter at -100 occasionally even though I am only using 13Ah Hawkers (tough
little bastards) For accelleration I can ask 250A monentarily on a fresh
charge. Not too good for them, but they were surplus and cheap.
One thing I almost never hear when people are discussing the merits of regen
is that the large surface charge will really get you off the line without
taxing the remaining battery charge too much.
Back to the tech. My regen with this controller does taper a bit with speed
but in my first gear I can regen right to a stop. Regen is strong enough to
be the noisiest operation due to reverse torque on the transmission. Regen is
also stronger when the batteries are not fully charged.
So it sounds like your etek and millipak is operating just like mine except
my gearing is lower.
Of course none of this will be of help to you if you don't have a
calibrator.
Oh and if you learn to use a footbrake pot for variable regen please let me
know I would love to try it out.
Rick Miller
Dirty Green Kawasaki
************************************** See what's free at http://www.aol.com.
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