EV Digest 3935
Topics covered in this issue include:
1) Re: Impressive NiMH conversion on the Web
by Derrick J Brashear <[EMAIL PROTECTED]>
2) Re: High current draw from floodies, was RE: Motor Amps, Battery Amps ?
by Lee Hart <[EMAIL PROTECTED]>
3) Re: Impressive NiMH conversion on the Web
by "Patrick Maston" <[EMAIL PROTECTED]>
4) Re: Impressive NiMH conversion on the Web
by [EMAIL PROTECTED]
5) Re: Sealed PbA battery Options
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
6) Re: Modular Charger
by Victor Tikhonov <[EMAIL PROTECTED]>
7) Re: Modular Charger
by Victor Tikhonov <[EMAIL PROTECTED]>
8) Re: Modular Charger
by Eric Poulsen <[EMAIL PROTECTED]>
9) Re: High current draw from floodies, was RE: Motor Amps, Battery Amps ?
by "Chuck Hursch" <[EMAIL PROTECTED]>
10) Tango news
by "Mark Thomasson" <[EMAIL PROTECTED]>
11) Re: High current draw from floodies, was RE: Motor Amps, Battery
Amps ?
by Nick Viera <[EMAIL PROTECTED]>
12) Re: Impressive NiMH conversion on the Web
by Victor Tikhonov <[EMAIL PROTECTED]>
13) Re: Modular Charger
by "Rich Rudman" <[EMAIL PROTECTED]>
14) Re: High current draw from floodies, was RE: Motor Amps, Battery
Amps ?
by Nick Viera <[EMAIL PROTECTED]>
15) Re: Impressive NiMH conversion on the Web
by Victor Tikhonov <[EMAIL PROTECTED]>
16) Re: High current draw from floodies, was RE: Motor Amps, Battery
Amps ?
by Nick Viera <[EMAIL PROTECTED]>
--- Begin Message ---
On Mon, 29 Nov 2004, Charles Whalen wrote:
Hi Carl,
Impressive indeed! Great looking car and project! Hope you'll keep us
updated on your progress.
Regarding the self-sealing LRR tires, do you know where Saturn got them,
i.e. who actually manufactures them, the make and model? Like most tires, I
assume that is probably stated on the tire, right? Do you happen to know if
it was it a one-time limited production run done only for the EV1, or is it
possible to actually special order these tires from whoever the manufacturer
is? Did you yourself buy them from a Saturn dealer in California, or did
you get them somewhere else?
Michelin Proxima, IIRC. I have a set on my car now,m but they're
dry-rotting!
--- End Message ---
--- Begin Message ---
Bob Bath wrote:
> Nick, your post was most timely, and Lee's response
> leaves me a bit distressed too. With my 18 x 8V
> floodies, 1.75 VPC x 72 cells is 126V. I am _certain_
> I have periodic voltage sags below that, especially
> when I live at the top of a rather steep hill (20 sec
> load, taking it to around 100V)! On the bright
> side, my e-Meter rarely goes below 1/2 full (1/2 empty
> (;-p), yet it looks like I've already screwed the
> pack, by this analysis.
The fundamental point is that a single voltage measurement of total pack
voltage tells you nothing about what individual cells are doing. You
simply don't know if you're dragging a "dead mule" in the traces.
I think the simplest thing you can add is my Battery Bridge light. This
is just three LEDs and two resistors. You can do the same thing with two
resistors and a multimeter. What it does is compare the voltages of the
two halves of the pack voltage. If there is a 2v difference, you have a
dead cell in the low half-pack. Let up on the throttle until the voltage
difference is less than 2v, or park and let the pack rest awhile, or
charge it.
> Sheesh, I detest lead, I detest not being able to
> monitor individual cells, and I'm not so excited about
> stressing a new pack during the winter when I already
> have reduced capacity!
It's not just lead-acid; you have this problem with any type.
--
"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 ---
According to a site I found on the web, you are correct: Michelin
Proxima RR, P175/65R14, self-sealing, 50 psi max inflation.
Patrick
>>> [EMAIL PROTECTED] 11/29/04 12:20:37 PM >>>
On Mon, 29 Nov 2004, Charles Whalen wrote:
> Hi Carl,
>
> Impressive indeed! Great looking car and project! Hope you'll keep
us
> updated on your progress.
>
> Regarding the self-sealing LRR tires, do you know where Saturn got
them,
> i.e. who actually manufactures them, the make and model? Like most
tires, I
> assume that is probably stated on the tire, right? Do you happen to
know if
> it was it a one-time limited production run done only for the EV1, or
is it
> possible to actually special order these tires from whoever the
manufacturer
> is? Did you yourself buy them from a Saturn dealer in California, or
did
> you get them somewhere else?
Michelin Proxima, IIRC. I have a set on my car now,m but they're
dry-rotting!
--- End Message ---
--- Begin Message ---
Prius Battery Packs
A quick search of one of the used parts (from wrecked autos) recyclers on
the web that I have used in the past showed 62 wrecked Prius models 2001 to
2003. The NiMH battery pack from one was confirmed to be $600 including
shipping
to Colorado. Expect to pay a bit more or less depending on shipping distance.
So they are definitely available at reasonable prices understanding that the
buyer has some small risk.
I also found that most of these types of web sites won't let you search for
just the battery pack, so be creative, search for an electric motor and you
will uncover the vehicles, then call or email the salvage company to confirm
the availability of the battery pack, price and condition/replacement/return
policy.
- Mike Bachand
[EMAIL PROTECTED] (mailto:[EMAIL PROTECTED])
Denver Electric Vehicle Council
--- End Message ---
--- Begin Message ---
I'm not sure why there isn't more NiCad in racing. The batteries I have put
out 1,800 amps per each 1.2v cell. That is in a 3.4 pound package. Less
sag with Nicad also. With Saft a 120v pack would give a small car close to
a hundred mile range. Cost is high though. over 10k for a 120v pack
weighing 750 pounds. Using Aircraft NiCads my cost was 3k for a 1000 pound
pack. Lawrence Rhodes......
----- Original Message -----
From: "John Westlund" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 28, 2004 8:53 PM
Subject: Sealed PbA battery Options
I'm looking to get a fairly decent amount of range, and the
Exides don't appear as if they would provide it.
I hear Optimas have suffered a significant decrease in
quality since their production shifted overseas. Is this
true? The conversions that used the earlier Optimas had such
great range for lead acid EVs.
Compared to the Exides, Optimas give excellent range, at
least according to simulations. The Exides only have about
270 deliverable wh per battery to full discharge, which
being 41 pounds each, is only about 13 wh/kilogram at the
1/2 hr rate(about 15-16 wh/kg at the 1 hr rate), while the
Optimas seem to have far more than that.
Does Hawker Genesis still make its sealed lead acid
batteries that the racers have used? Rich Brown has been
able to get 40 miles highway from Dualin 7 with about 800
pounds of these according to his austinev.org page. I'm
guessing that's to a full discharge, and not 80%.
Gel Cel batteries have excellent capacity, but are also
lacking in power I hear, usually not able to deliver more
than 300 amps reliably.
So what are my options for a battery that will allow about
120 horsepower(or more) for an 800 pound pack for a racing
application? Are Optimas still any good to use, or is it
taking a risk to use them? I'm not looking to break any
world records, I'm looking at a conversion that will use a
9-inch ADC motor or WarP9 motor and a Zilla 1k, with at
least a 192V pack, wanting to pull a 1/4 mile time in the
mid 15s or faster. But I also want at least 30 miles range
to 80% DoD at 60 MPH, assuming a consumption of less than
200 wh/mile. AC Propulsion showed 80+ mile ranges under
these constraints was possible, using a setup that would be
within 15% more efficient than what I'm looking at using,
but they used Optimas that may now be different in quality
than they were then. Exides look very dissappointing for
range.
Any suggestions?
I'm sure Wayland can give me estimates on how the Deka
Intimidators would fare. Can't wait for Rich to get ahold of
one to give the real figures.
--- End Message ---
--- Begin Message ---
A big advantage of modular charging system is you don't need
balancing system as each battery is taken care of
individually. And, discussing one bulk charger choice vs.
modular chargers you must include balancing hardware to the bulk
charger (so the batteries are seeing about the same treatment),
else it is not quite apples to apples comparison.
Once you add more-less smart balancers the reliability problem
of failure of one returns, althoug the bulk charge is done right
and the chances ruining one battery is greatly reduced.
But, the regs usually connected by some sort of a bus or at least
common signal, which may as well be part of the modular chargers
system. Each charger doesn't have to be 20 times more reliable
for 20 battery system. They all just HAVE to shut down in case
either one fails, and implementing that is quite trivial.
I believe the modular charging is not as bad choice as it may have
been presented. If one got disasterous result, it was just a
negligence to make all the chargers to talk to each other and
taking chances hoping for the best while consequences of such
decision are (were) very obvious.
Victor
Rich Rudman wrote:
----- Original Message -----
From: "John Wayland" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 21, 2004 5:42 PM
Subject: Re: Modular Charger
Hello to All,
From: Mike Chancey
Who is using modular chargers (one charger per battery) and how well
have
they worked out?
Damon Henry wrote:
The design could include a common buss connection for a master unit's
control
over current, constant voltage selection point, and cut-off timer
adjustment. Such a
system could then be competitive in charging performance to a Manzanita
Micro PFC series
chargers, but the cost thing would surely be way out of line....and then,
there's still
that nagging worry, did all the chargers really get all the batteries
fully charged?
See Ya......John Wayland
Thanks John for this Generous post.
Add copy is really nice when you don't ask for it.
Also for the first time in years I do not have a exstensive back log.
Lead times are in days right now not weeks.
--- End Message ---
--- Begin Message ---
Eric, I suppose this is not the news for you,, but the cost of micro
itself is
a small fraction (~5%) of the cost of finished product.
Get twice as powerful micro and its cost may rise may be to 8%...
Victor
Eric Poulsen wrote:
Rich,
The PIC line of microcontrollers are especially cheap for the OTP
version.
Rich Rudman wrote:
--- End Message ---
--- Begin Message ---
Just out of curiosity, what IS the major cost?
I'd assume that the #1 cost is labor time, followed by the cost of the
PCB if you're ordering small quantities.
I know the regs are $10 for a blank PCB + parts list. How much are the
parts?
I'd think that these items would benefit greatly from economy of scale,
plus cheap labor.
Victor Tikhonov wrote:
Eric, I suppose this is not the news for you,, but the cost of micro
itself is
a small fraction (~5%) of the cost of finished product.
Get twice as powerful micro and its cost may rise may be to 8%...
Victor
Eric Poulsen wrote:
Rich,
The PIC line of microcontrollers are especially cheap for the OTP
version.
Rich Rudman wrote:
--- End Message ---
--- Begin Message ---
Hi Bob,
I wouldn't stress out too much about going below the 1.75VPC
level. You do what you have to do to get up the hill. People
who live in hilly places around the Bay Area just accept it as a
fact of life that they will get reduced life out of their
batteries.
On my 96V (16 * 6V (US125 or Trojan T125 235A-hr @ C/20)) Rabbit,
I regularly pull them down below 1.75VPC traversing the hills
here in Marin (on the other side of the Golden Gate from San
Francisco). If I want to go over to downtown San Rafael, it's
300-325A northbound over Wolfe Grade at 30mph (the speedlimit) or
a little more in 2nd gear for about a minute to stay with
traffic. When the batteries were newer, they had less voltage
sag and would roll up to 35mph or a little more at that amp draw.
Coming back southbound from San Rafael, the road is even steeper,
but very windy, so I get to chase the gas cars in second gear
(Curtis1231C - yes, the old 1221B - no in 1st gear (the gar cars
backed up behind me then)). Battery amp draws go to about 400A
pulling out of the steep corners on this southbound climb.
Alternatives to the climb? Well, if I want to go over to eastern
San Rafael, I can plan on hustling up the onramp onto Hi101
northbound with the gas cars for more 350A draws for 30 seconds
or so. Coming back that way? Another long up-hill climb out of
a very tightly turning on-ramp. 55mph freeway. I'm in the right
lane at 40mph or a little more southbound at 300-350A. The only
semi-flat routes to San Rafael are around the east and west ends
of this Cal-Park hill, but it seems like my batteries arrive at a
lower SOC than if I just get it done with and go over the hill
the more direct routes.
The whole area and the freeway (Hi101) are peppered with long
steep grades. I like the terrain, my batteries don't. I almost
think a set of Optimas or Exide Orbitals would be better
(especially when I read John Wayland's enthusiastic posts), but I
don't have my own shop in an apt, and it would be a big expensive
upgrade.
The steep hill up to my apt is the trip-end killer at an average
of 20% grade. No place to pull off the narrow long sweeping
curve once past the lower apt complexes. After only a 4 mile
trip, when I come up the hill, I've measured the battery pack at
79V (1.65VPC) under a ~350A load in 1st gear. That's when the
battery pack had just a short distance on it, and I'm doing
17-18mph. I've done that same hill from 49 miles away (once,
from Redwood City on the Peninsula just south of San Francisco),
and crawled up it without moving the speedo off the 10mph peg (it
was probably about ~10mph climb). I don't know what the VPC
readings would've been, but I bet they were low (it's conceivable
the 1231C had tamped down with its undervoltage limit of 66V - if
I recall the # correctly). 66V => 1.38VPC. Yet, a year later I
still had 60-70 mile range on this same terrain (if I don't want
to come back up my hill) with the same pack (3-years old by
then). So they will survive, to a point.
Yes, lead makes me feel like I want to tear my hair out
sometimes. It's heavy and the batteries are cheaply made with
lots of variances. I wish I knew how to build a battery
management system and had the time, but obtaining the skills is
one of the biggest reasons I plow through all the EVDL messages.
And, if battery life became numero uno, I'd move to the flats
down in Sili Valley... My EV gets me around, and that's what I
intended for it to do when I built it back in 1994.
If you are really concerned about pack longetivity, get a
bulldozer and flatten your hill. Next to that, don't draw the
pack down as far as you might be tempted to before you come back
home. Try to build up a charging infrastructure in your area, so
your batteries can charge while your engaging in other activities
(shopping), so they're fresher, and less likely to reverse a
cell, when you do your hill. Also, the first year or two you
have your pack is Honeymoon Time. After that, well, you know
what I mean..., you live with them. And later on, it's like
their Golden Years.
Chuck
----- Original Message -----
From: "Bob Bath" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 28, 2004 11:25 PM
Subject: Re: High current draw from floodies, was RE: Motor Amps,
Battery Amps ?
> Nick, your post was most timely, and Lee's response
> leaves me a bit distressed too. With my 18 x 8V
> floodies, 1.75 VPC x72 cells is 126V. I am _certain_
> I have periodic voltage sags below that, especially
> when I live at the top of a rather steep hill (20 sec
> load, taking it to around 100V)!!!. On the bright
> side, my e-Meter rarely goes below 1/2 full (1/2 empty
> (;-p), yet it looks like I've already screwed the
> pack, by this analysis.
> Sheesh, I detest lead, I detest not being able to
> monitor individual cells, and I'm not so excited about
> stressing a new pack during the winter when I already
> have reduced capacity!
>
> --- Lee Hart <[EMAIL PROTECTED]> wrote:
>
> > Nick Viera wrote:
> > > But you've never really explained how to determine
> > if a battery has
> > > reversed cells.
> >
> > A normal flooded lead-acid cell has a no-voltage of
> > 1.95v (dead) to
> > 2.12v (full) after it has sat idle for at least a
> > few hours. A normal
> > cell also has low internal resistance; like 0.001
> > ohm when fully
> > charged, to 0.01 ohm when approaching dead.
> >
> > A reversed cell will have a drastically lower
> > voltage; often its
> > polarity will be REVERSED, i.e. it measures -2v
> > instead of +2v. The
> > internal resistance of a cell goes up drastically as
> > it approaches dead
> > (to several ohms!). When the cell reverses, the
> > resistance goes down
> > again, but even when re-reversed (i.e. fully charged
> > in the correct
> > direction), its internal resistance will have
> > permanently increased to
> > many times higher than normal.
> >
> > The consequences of a reversed cell are a) much less
> > amphour capacity,
> > b) much more voltage sag under load, c) much shorter
> > life, and d)
> > serious heating, gassing, and water loss problems.
> >
> > You can't usually get at the individual cell
> > voltages; all you can
> > measure is the total battery voltage. So, you have
> > to guess at the
> > individual cell voltages from the total battery
> > voltage. For your 8v
> > batteries (four 2v cells), a voltage under 6v
> > implies that you have a
> > reversed cell (i.e. three cells at 2.xx volts, and
> > one at essentially
> > zero volts).
> >
> > > I'm under the impression that reversed cells would
> > significantly
> > > reduce range and performance. I haven't noticed
> > this. The range and
> > > performance have been pretty much the same since
> > day one.
> >
> > A single reversed cell isn't obvious. All the strong
> > cells mask the
> > weakness. The total pack voltage is only reduced
> > about 2v, which is too
> > small to notice, given the large variations in pack
> > voltage due to
> > state-of-charge and load current.
> >
> > Your range and top speed might not even appear to be
> > significantly
> > affected with a reversed cell -- at first. The rest
> > of the cells can
> > 'drag along' the dead one -- for a while. But,
> > remember "20-Mule Team
> > Borax"? Running a pack with a reversed cell is like
> > driving that 20-mule
> > team through the desert with one dead mule dragging
> > in its harness. The
> > other 19 can do it for a while, but will tire
> > quickly. Then, one by one,
> > they will die early, and you'll be dragging their
> > corpses along, too.
> > You'll kill the whole team this way!
> >
> > > And yes, I now have a dash mounted digital volt
> > meter, and I have
> > > seen the voltage sag pretty low for very short
> > amounts of time
> > > during hard acceleration. 115 volts happened once,
> > but that's
> > > it. I've not done this intentionally. These
> > batteries have a lot
> > > of voltage sag under large current draws.
> >
> > I forget; do you have 20 8v batteries, for a 160v
> > pack? 115v on a 160v
> > pack is about 1.44v/cell. The lowest you should ever
> > go is 1.75v/cell,
> > or 140v under load. When you pull the pack as a
> > whole down to 115v, you
> > are almost certainly reversing one or more cells.
> >
> > > Here's the voltages after a recent short trip:
> > > 8.52v - Battery #3
> > > 8.51v - Battery #5
> > > 8.50v - Battery #15
> > > 8.49v - Battery #6,8,9,10,12,13,14,16,17
> > > 8.48v - Battery #2,4,7,11,18,20
> > > 8.47v - Battery #1
> > > 8.46v - Battery #19
> >
> > Those are all pretty good; but they only reflect
> > voltages near full
> > charge. What you need to do to find weak cells is to
> > drive near the
> > limits of your range, and measure the individual
> > battery voltages
> > immediately after your drive, BEFORE you do any
> > charging. Any weak or
> > reversed cells will immediately stand out as a
> > battery that is about 2v
> > less than the rest.
> >
> > > I also took the voltages while the Jeep was
> > charging (near the end of
> > > the charge) today, they were:
> > > 9.58v - Battery #19
> > > 9.59v - Battery #1
> > > 9.63v - Battery #2,6,7,8
> > > 9.64v - Battery #4
> > > 9.65v - Battery #17
> > > 9.67v - Battery #9,16
> > > 9.71v - Battery #11
> > > 9.73v - Battery #3
> > > 9.75v - Battery #14
> > > 9.76v - Battery #10,13,18
> > > 9.77v - Battery #5
> > > 9.82v - Battery #12,20
> > > 9.84v - Battery #15
> >
> > These don't really mean anything.
> >
> > #19 and #1 are probably the batteries with the
> > lowest amphour capacity.
> > But that does not mean they are bad. You will
> > *always have some battery
> > with the lowest amphour capacity.
> > --
> > "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
> >
> >
>
>
> =====
> '92 Honda Civic sedan, 144V
> ____
> __/__|__\ __
> =D-------/ - - \
> 'O'-----'O'-'
> Would you still drive your car if the tailpipe came out of the
steering wheel? Are you saving any gas for your kids?
>
>
>
> __________________________________
> Do you Yahoo!?
> Meet the all-new My Yahoo! - Try it today!
> http://my.yahoo.com
>
>
--- End Message ---
--- Begin Message ---
See December Wired magazine, page 139 for one page Tango article. Also see:
http://www.commutercars.com/
Mark T.
--- End Message ---
--- Begin Message ---
Lee,
Thank you for the detailed explanation!
I'll continue to monitor my battery voltages immediately after I return
from future trips to see if I can spot any problematic batteries. Of
course, I'm monitoring each battery by hand at this point. I'm still
working on some sort of system so I can monitor the individual voltages
of all the batteries from the dash.
I'll try to be more conscience about not going below 140 volts, but
there are some times that it is unavoidable if I want to get up a hill
in any reasonable amount of time (and prevent being run over by some
impatient jerk).
What is frustrating is that it seems almost any load over ~225 amps
causes my pack voltage to sag a lot (sometimes to or a bit below 140v).
The exception being the first 5 or so miles after just being charged,
when the pack seems to hold above 150 volts even under heavy loads).
Since I haven't had an in-dash volt meter the entire time, I can't tell
whether the voltage sag has worsened since the batteries were brand new,
or if they have always had a lot of voltage sag...
Though, it is sounding like I have some reversed cells :-/
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
---------------------------------------------
On Mon, 2004-11-29 at 01:32, Lee Hart wrote:
> Nick Viera wrote:
> > But you've never really explained how to determine if a battery has
> > reversed cells.
>
> A normal flooded lead-acid cell has a no-voltage of 1.95v (dead) to
> 2.12v (full) after it has sat idle for at least a few hours. A normal
> cell also has low internal resistance; like 0.001 ohm when fully
> charged, to 0.01 ohm when approaching dead.
>
> A reversed cell will have a drastically lower voltage; often its
> polarity will be REVERSED, i.e. it measures -2v instead of +2v. The
> internal resistance of a cell goes up drastically as it approaches dead
> (to several ohms!). When the cell reverses, the resistance goes down
> again, but even when re-reversed (i.e. fully charged in the correct
> direction), its internal resistance will have permanently increased to
> many times higher than normal.
>
> The consequences of a reversed cell are a) much less amphour capacity,
> b) much more voltage sag under load, c) much shorter life, and d)
> serious heating, gassing, and water loss problems.
>
> You can't usually get at the individual cell voltages; all you can
> measure is the total battery voltage. So, you have to guess at the
> individual cell voltages from the total battery voltage. For your 8v
> batteries (four 2v cells), a voltage under 6v implies that you have a
> reversed cell (i.e. three cells at 2.xx volts, and one at essentially
> zero volts).
>
> > I'm under the impression that reversed cells would significantly
> > reduce range and performance. I haven't noticed this. The range and
> > performance have been pretty much the same since day one.
>
> A single reversed cell isn't obvious. All the strong cells mask the
> weakness. The total pack voltage is only reduced about 2v, which is too
> small to notice, given the large variations in pack voltage due to
> state-of-charge and load current.
>
> Your range and top speed might not even appear to be significantly
> affected with a reversed cell -- at first. The rest of the cells can
> 'drag along' the dead one -- for a while. But, remember "20-Mule Team
> Borax"? Running a pack with a reversed cell is like driving that 20-mule
> team through the desert with one dead mule dragging in its harness. The
> other 19 can do it for a while, but will tire quickly. Then, one by one,
> they will die early, and you'll be dragging their corpses along, too.
> You'll kill the whole team this way!
>
> > And yes, I now have a dash mounted digital volt meter, and I have
> > seen the voltage sag pretty low for very short amounts of time
> > during hard acceleration. 115 volts happened once, but that's
> > it. I've not done this intentionally. These batteries have a lot
> > of voltage sag under large current draws.
>
> I forget; do you have 20 8v batteries, for a 160v pack? 115v on a 160v
> pack is about 1.44v/cell. The lowest you should ever go is 1.75v/cell,
> or 140v under load. When you pull the pack as a whole down to 115v, you
> are almost certainly reversing one or more cells.
>
> > Here's the voltages after a recent short trip:
> > 8.52v - Battery #3
> > 8.51v - Battery #5
> > 8.50v - Battery #15
> > 8.49v - Battery #6,8,9,10,12,13,14,16,17
> > 8.48v - Battery #2,4,7,11,18,20
> > 8.47v - Battery #1
> > 8.46v - Battery #19
>
> Those are all pretty good; but they only reflect voltages near full
> charge. What you need to do to find weak cells is to drive near the
> limits of your range, and measure the individual battery voltages
> immediately after your drive, BEFORE you do any charging. Any weak or
> reversed cells will immediately stand out as a battery that is about 2v
> less than the rest.
>
> > I also took the voltages while the Jeep was charging (near the end of
> > the charge) today, they were:
> > 9.58v - Battery #19
> > 9.59v - Battery #1
> > 9.63v - Battery #2,6,7,8
> > 9.64v - Battery #4
> > 9.65v - Battery #17
> > 9.67v - Battery #9,16
> > 9.71v - Battery #11
> > 9.73v - Battery #3
> > 9.75v - Battery #14
> > 9.76v - Battery #10,13,18
> > 9.77v - Battery #5
> > 9.82v - Battery #12,20
> > 9.84v - Battery #15
>
> These don't really mean anything.
>
> #19 and #1 are probably the batteries with the lowest amphour capacity.
> But that does not mean they are bad. You will *always have some battery
> with the lowest amphour capacity.
--- End Message ---
--- Begin Message ---
This is one of my cutomers' (Carlton Brown ) vehicle;
Using 18kW rated Siemens motor (1PV5105WS12) and
Simovert inverter.
Victor
Mike Chancey wrote:
Hi folks,
I just stumbled onto this site this morning:
http://www.electric7.com/
It is an AC drive NiMH powered EV project, using NiMH batteries
salvaged from hybrid electric cars. Anyone know anything about this
one? Do those look like Prius batteries?
Thanks,
Mike Chancey,
'88 Civic EV
'95 Solectria Force
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
--- End Message ---
--- Begin Message ---
Guys...
It's not like I have not done a Micro based product... I have, and the
micro was not the big cost. It was a MC68HC705 at the time...The software
was the hard to support item.
I actually got it written, and had Joe clean up the Bugs. But I laid down
the foundation.
So... I don't have a fear of Micros. I have a respect for them, and Keep a
eye on Non digital circuits, and how well they do some thing and how well a
micro does other stuff.
Us gray hairs... have been on both sides of the issue.
Now that I have a better production crew, I might get some micro time for
the BLDC/AC drive project. Wanna have a 150 MIPS DSP on a Regulator.????
That would be a nice test project.
Also keep in mind I am making and shipping a few hundred Regs a
month....Right now.
Digi based Regs could happen in days if I wanted them to....
----- Original Message -----
From: "Eric Poulsen" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, November 29, 2004 3:10 PM
Subject: Re: Modular Charger
> Just out of curiosity, what IS the major cost?
>
> I'd assume that the #1 cost is labor time, followed by the cost of the
> PCB if you're ordering small quantities.
>
> I know the regs are $10 for a blank PCB + parts list. How much are the
> parts?
>
> I'd think that these items would benefit greatly from economy of scale,
> plus cheap labor.
>
> Victor Tikhonov wrote:
>
> > Eric, I suppose this is not the news for you,, but the cost of micro
> > itself is
> > a small fraction (~5%) of the cost of finished product.
> > Get twice as powerful micro and its cost may rise may be to 8%...
> >
> > Victor
> >
> > Eric Poulsen wrote:
> >
> >> Rich,
> >>
> >> The PIC line of microcontrollers are especially cheap for the OTP
> >> version.
> >>
> >> Rich Rudman wrote:
> >>
> >
> >
>
--- End Message ---
--- Begin Message ---
Hi,
> I think the simplest thing you can add is my Battery Bridge light.
> This is just three LEDs and two resistors. You can do the same thing
> with two resistors and a multimeter.
Do you have a schematic (or was it already posted and I missed it)? I
have a bunch of extra LEDs and resistors floating around here, so I'd
like to try this, at least until I can get around to building more
advanced circuits based on the LM3914 or something...
Thanks
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
---------------------------------------------
On Mon, 2004-11-29 at 12:22, Lee Hart wrote:
> Bob Bath wrote:
> > Nick, your post was most timely, and Lee's response
> > leaves me a bit distressed too. With my 18 x 8V
> > floodies, 1.75 VPC x 72 cells is 126V. I am _certain_
> > I have periodic voltage sags below that, especially
> > when I live at the top of a rather steep hill (20 sec
> > load, taking it to around 100V)! On the bright
> > side, my e-Meter rarely goes below 1/2 full (1/2 empty
> > (;-p), yet it looks like I've already screwed the
> > pack, by this analysis.
>
> The fundamental point is that a single voltage measurement of total pack
> voltage tells you nothing about what individual cells are doing. You
> simply don't know if you're dragging a "dead mule" in the traces.
>
> I think the simplest thing you can add is my Battery Bridge light. This
> is just three LEDs and two resistors. You can do the same thing with two
> resistors and a multimeter. What it does is compare the voltages of the
> two halves of the pack voltage. If there is a 2v difference, you have a
> dead cell in the low half-pack. Let up on the throttle until the voltage
> difference is less than 2v, or park and let the pack rest awhile, or
> charge it.
>
> > Sheesh, I detest lead, I detest not being able to
> > monitor individual cells, and I'm not so excited about
> > stressing a new pack during the winter when I already
> > have reduced capacity!
>
> It's not just lead-acid; you have this problem with any type.
--- End Message ---
--- Begin Message ---
Carlton uses BRUSA NLG513-TA charger
Eats anything from 120VAC to 240VAC, similar to PFC series,
only isolated.
Victor
Electro Automotive wrote:
I just stumbled onto this site this morning:
http://www.electric7.com/
It is an AC drive NiMH powered EV project, using NiMH batteries
salvaged from hybrid electric cars. Anyone know anything about this
one? Do those look like Prius batteries?
What I want to know is, have there REALLY been enough hybrids junked
already to be able to salvage batteries?
And what are they using for a charger? Those photos never loaded on
my computer.
Shari Prange
Electro Automotive POB 1113 Felton CA 95018-1113 Telephone 831-429-1989
http://www.electroauto.com [EMAIL PROTECTED]
Electric Car Conversion Kits * Components * Books * Videos * Since 1979
--- End Message ---
--- Begin Message ---
Hi,
> If you are really concerned about pack longetivity, get a
> bulldozer and flatten your hill.
You make it sound so simple :-)
Anyways, It makes me feel better to hear that I'm not the only one
experiencing a lot of voltage sag.
-Nick
1988 Jeep Cherokee 4x4 EV
http://Go.DriveEV.com/
-------------------------------------------------
On Mon, 2004-11-29 at 16:16, Chuck Hursch wrote:
> Hi Bob,
>
> I wouldn't stress out too much about going below the 1.75VPC
> level. You do what you have to do to get up the hill. People
> who live in hilly places around the Bay Area just accept it as a
> fact of life that they will get reduced life out of their
> batteries.
>
> On my 96V (16 * 6V (US125 or Trojan T125 235A-hr @ C/20)) Rabbit,
> I regularly pull them down below 1.75VPC traversing the hills
> here in Marin (on the other side of the Golden Gate from San
> Francisco). If I want to go over to downtown San Rafael, it's
> 300-325A northbound over Wolfe Grade at 30mph (the speedlimit) or
> a little more in 2nd gear for about a minute to stay with
> traffic. When the batteries were newer, they had less voltage
> sag and would roll up to 35mph or a little more at that amp draw.
> Coming back southbound from San Rafael, the road is even steeper,
> but very windy, so I get to chase the gas cars in second gear
> (Curtis1231C - yes, the old 1221B - no in 1st gear (the gar cars
> backed up behind me then)). Battery amp draws go to about 400A
> pulling out of the steep corners on this southbound climb.
> Alternatives to the climb? Well, if I want to go over to eastern
> San Rafael, I can plan on hustling up the onramp onto Hi101
> northbound with the gas cars for more 350A draws for 30 seconds
> or so. Coming back that way? Another long up-hill climb out of
> a very tightly turning on-ramp. 55mph freeway. I'm in the right
> lane at 40mph or a little more southbound at 300-350A. The only
> semi-flat routes to San Rafael are around the east and west ends
> of this Cal-Park hill, but it seems like my batteries arrive at a
> lower SOC than if I just get it done with and go over the hill
> the more direct routes.
>
> The whole area and the freeway (Hi101) are peppered with long
> steep grades. I like the terrain, my batteries don't. I almost
> think a set of Optimas or Exide Orbitals would be better
> (especially when I read John Wayland's enthusiastic posts), but I
> don't have my own shop in an apt, and it would be a big expensive
> upgrade.
>
> The steep hill up to my apt is the trip-end killer at an average
> of 20% grade. No place to pull off the narrow long sweeping
> curve once past the lower apt complexes. After only a 4 mile
> trip, when I come up the hill, I've measured the battery pack at
> 79V (1.65VPC) under a ~350A load in 1st gear. That's when the
> battery pack had just a short distance on it, and I'm doing
> 17-18mph. I've done that same hill from 49 miles away (once,
> from Redwood City on the Peninsula just south of San Francisco),
> and crawled up it without moving the speedo off the 10mph peg (it
> was probably about ~10mph climb). I don't know what the VPC
> readings would've been, but I bet they were low (it's conceivable
> the 1231C had tamped down with its undervoltage limit of 66V - if
> I recall the # correctly). 66V => 1.38VPC. Yet, a year later I
> still had 60-70 mile range on this same terrain (if I don't want
> to come back up my hill) with the same pack (3-years old by
> then). So they will survive, to a point.
>
> Yes, lead makes me feel like I want to tear my hair out
> sometimes. It's heavy and the batteries are cheaply made with
> lots of variances. I wish I knew how to build a battery
> management system and had the time, but obtaining the skills is
> one of the biggest reasons I plow through all the EVDL messages.
> And, if battery life became numero uno, I'd move to the flats
> down in Sili Valley... My EV gets me around, and that's what I
> intended for it to do when I built it back in 1994.
>
> If you are really concerned about pack longetivity, get a
> bulldozer and flatten your hill. Next to that, don't draw the
> pack down as far as you might be tempted to before you come back
> home. Try to build up a charging infrastructure in your area, so
> your batteries can charge while your engaging in other activities
> (shopping), so they're fresher, and less likely to reverse a
> cell, when you do your hill. Also, the first year or two you
> have your pack is Honeymoon Time. After that, well, you know
> what I mean..., you live with them. And later on, it's like
> their Golden Years.
>
> Chuck
>
> ----- Original Message -----
> From: "Bob Bath" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Sunday, November 28, 2004 11:25 PM
> Subject: Re: High current draw from floodies, was RE: Motor Amps,
> Battery Amps ?
>
>
> > Nick, your post was most timely, and Lee's response
> > leaves me a bit distressed too. With my 18 x 8V
> > floodies, 1.75 VPC x72 cells is 126V. I am _certain_
> > I have periodic voltage sags below that, especially
> > when I live at the top of a rather steep hill (20 sec
> > load, taking it to around 100V)!!!. On the bright
> > side, my e-Meter rarely goes below 1/2 full (1/2 empty
> > (;-p), yet it looks like I've already screwed the
> > pack, by this analysis.
> > Sheesh, I detest lead, I detest not being able to
> > monitor individual cells, and I'm not so excited about
> > stressing a new pack during the winter when I already
> > have reduced capacity!
> >
> > --- Lee Hart <[EMAIL PROTECTED]> wrote:
> >
> > > Nick Viera wrote:
> > > > But you've never really explained how to determine
> > > if a battery has
> > > > reversed cells.
> > >
> > > A normal flooded lead-acid cell has a no-voltage of
> > > 1.95v (dead) to
> > > 2.12v (full) after it has sat idle for at least a
> > > few hours. A normal
> > > cell also has low internal resistance; like 0.001
> > > ohm when fully
> > > charged, to 0.01 ohm when approaching dead.
> > >
> > > A reversed cell will have a drastically lower
> > > voltage; often its
> > > polarity will be REVERSED, i.e. it measures -2v
> > > instead of +2v. The
> > > internal resistance of a cell goes up drastically as
> > > it approaches dead
> > > (to several ohms!). When the cell reverses, the
> > > resistance goes down
> > > again, but even when re-reversed (i.e. fully charged
> > > in the correct
> > > direction), its internal resistance will have
> > > permanently increased to
> > > many times higher than normal.
> > >
> > > The consequences of a reversed cell are a) much less
> > > amphour capacity,
> > > b) much more voltage sag under load, c) much shorter
> > > life, and d)
> > > serious heating, gassing, and water loss problems.
> > >
> > > You can't usually get at the individual cell
> > > voltages; all you can
> > > measure is the total battery voltage. So, you have
> > > to guess at the
> > > individual cell voltages from the total battery
> > > voltage. For your 8v
> > > batteries (four 2v cells), a voltage under 6v
> > > implies that you have a
> > > reversed cell (i.e. three cells at 2.xx volts, and
> > > one at essentially
> > > zero volts).
> > >
> > > > I'm under the impression that reversed cells would
> > > significantly
> > > > reduce range and performance. I haven't noticed
> > > this. The range and
> > > > performance have been pretty much the same since
> > > day one.
> > >
> > > A single reversed cell isn't obvious. All the strong
> > > cells mask the
> > > weakness. The total pack voltage is only reduced
> > > about 2v, which is too
> > > small to notice, given the large variations in pack
> > > voltage due to
> > > state-of-charge and load current.
> > >
> > > Your range and top speed might not even appear to be
> > > significantly
> > > affected with a reversed cell -- at first. The rest
> > > of the cells can
> > > 'drag along' the dead one -- for a while. But,
> > > remember "20-Mule Team
> > > Borax"? Running a pack with a reversed cell is like
> > > driving that 20-mule
> > > team through the desert with one dead mule dragging
> > > in its harness. The
> > > other 19 can do it for a while, but will tire
> > > quickly. Then, one by one,
> > > they will die early, and you'll be dragging their
> > > corpses along, too.
> > > You'll kill the whole team this way!
> > >
> > > > And yes, I now have a dash mounted digital volt
> > > meter, and I have
> > > > seen the voltage sag pretty low for very short
> > > amounts of time
> > > > during hard acceleration. 115 volts happened once,
> > > but that's
> > > > it. I've not done this intentionally. These
> > > batteries have a lot
> > > > of voltage sag under large current draws.
> > >
> > > I forget; do you have 20 8v batteries, for a 160v
> > > pack? 115v on a 160v
> > > pack is about 1.44v/cell. The lowest you should ever
> > > go is 1.75v/cell,
> > > or 140v under load. When you pull the pack as a
> > > whole down to 115v, you
> > > are almost certainly reversing one or more cells.
> > >
> > > > Here's the voltages after a recent short trip:
> > > > 8.52v - Battery #3
> > > > 8.51v - Battery #5
> > > > 8.50v - Battery #15
> > > > 8.49v - Battery #6,8,9,10,12,13,14,16,17
> > > > 8.48v - Battery #2,4,7,11,18,20
> > > > 8.47v - Battery #1
> > > > 8.46v - Battery #19
> > >
> > > Those are all pretty good; but they only reflect
> > > voltages near full
> > > charge. What you need to do to find weak cells is to
> > > drive near the
> > > limits of your range, and measure the individual
> > > battery voltages
> > > immediately after your drive, BEFORE you do any
> > > charging. Any weak or
> > > reversed cells will immediately stand out as a
> > > battery that is about 2v
> > > less than the rest.
> > >
> > > > I also took the voltages while the Jeep was
> > > charging (near the end of
> > > > the charge) today, they were:
> > > > 9.58v - Battery #19
> > > > 9.59v - Battery #1
> > > > 9.63v - Battery #2,6,7,8
> > > > 9.64v - Battery #4
> > > > 9.65v - Battery #17
> > > > 9.67v - Battery #9,16
> > > > 9.71v - Battery #11
> > > > 9.73v - Battery #3
> > > > 9.75v - Battery #14
> > > > 9.76v - Battery #10,13,18
> > > > 9.77v - Battery #5
> > > > 9.82v - Battery #12,20
> > > > 9.84v - Battery #15
> > >
> > > These don't really mean anything.
> > >
> > > #19 and #1 are probably the batteries with the
> > > lowest amphour capacity.
> > > But that does not mean they are bad. You will
> > > *always have some battery
> > > with the lowest amphour capacity.
> > > --
> > > "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
> > >
> > >
> >
> >
> > =====
> > '92 Honda Civic sedan, 144V
> > ____
> > __/__|__\ __
> > =D-------/ - - \
> > 'O'-----'O'-'
> > Would you still drive your car if the tailpipe came out of the
> steering wheel? Are you saving any gas for your kids?
> >
> >
> >
> > __________________________________
> > Do you Yahoo!?
> > Meet the all-new My Yahoo! - Try it today!
> > http://my.yahoo.com
> >
> >
--- End Message ---
