EV Digest 5323
Topics covered in this issue include:
1) Re: Thanks for all the insight on my project
by Darin <[EMAIL PROTECTED]>
2) Re: Multi charger.
by "Mike Phillips" <[EMAIL PROTECTED]>
3) RE: Battery Pack Heating - Optima Hawker links
by "Roger Stockton" <[EMAIL PROTECTED]>
4) Re: Thanks for all the insight on my project
by Darin <[EMAIL PROTECTED]>
5) Re: Multi charger.
by [EMAIL PROTECTED]
6) Re: Multi charger.
by [EMAIL PROTECTED]
7) RE: Battery Pack Heating
by "Roger Stockton" <[EMAIL PROTECTED]>
8) RE: Would like large AGM with good EV user history
by "Roger Stockton" <[EMAIL PROTECTED]>
9) Re: Porsche 911 Was: How many amps driving my EV?
by Robert Baertsch <[EMAIL PROTECTED]>
10) RE: How many amps driving my EV?
by Cor van de Water <[EMAIL PROTECTED]>
11) Re: Battery Pack Heating
by "Mike Phillips" <[EMAIL PROTECTED]>
12) Re: How many amps driving my EV?
by "Mike Phillips" <[EMAIL PROTECTED]>
13) Battery sound monitoring
by "Mike Phillips" <[EMAIL PROTECTED]>
14) RE: Would like large AGM with good EV user history
by Cor van de Water <[EMAIL PROTECTED]>
--- Begin Message ---
Whoops!
had planned that to be a private message. ah, well, I guess it's not
like i just broadcast my credit card number (or something worse?) to all
you folks on the list!
- Darin
hey steve -
been following the conversation on the ev list about your conversion
specs. you sure sparked some interesting exchanges.
hope you get it sorted out to your satisfaction.
as for our budget NEV conversion, we got the host car up on jack stands
and started poking, pulling & banging the rust off the underside. it's
very "holey". we need to decide whether we're going to spend our time
fabricating patches & welding up something that will pass inspection, or
spending time (and money) looking for a more solid host car.
good luck!
- darin
--- End Message ---
--- Begin Message ---
Who is CE? What model charger are you looking at?
Mike
> Manzanita Micro >>
> Deltran is in busness in Flordia and the general public will pay
$27oo for 30
> charger bank.I plan to use CEs modular charger on the S10 pu also to
finish
> and float charge the 26ah hawkers as hawker recomends these on their
site.Your
> pfc20 will be used to bulk charge from a welder or the honda eu
gensets or
> house power.I personaly believe I would have battery issues if I
used just your
> pfc20to charge. Dennis Berube
>
--- End Message ---
--- Begin Message ---
Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
> I'm operating in a temperature range that makes this point mute.
You appear to be offering this data point as "proof" that it is OK to
operate your Optimas in the 30-40C range, which does make proper
understanding of what Optima's spec means relevant.
> As for float life, I don't see how it applies to EV's.
Quite simply: the same processes that cause elevated temperature to
shorten float life apply to cyclic use also. The effect of elevated
temperature is most obvious in float applications because essentially
the only two factors operating to limit battery life in this case are
temperature and quality of charge.
Elevated temperature *will* shorten your battery life in either duty,
all else being equal. If you decrease DOD, you may increase cycle life
sufficiently to more or less mask the reduction in life due to operating
at elevated temperature. If you cycle the batteries frequently enough,
you may be able to wear them out before the effects of elevated
temperature have time to become apparent.
> If my Hawkers life were cut in half to only 5 years, I'd be
> the happiest guy in town!! They barely reached half of 5 years.
Yours is a cyclic application, so life in terms of cycles is a better
indication of how well or poorly they are being treated. Taking 2.5yrs
to wear them out from cycling is, I think, sufficiently long that you
may well be able to see the effects of battery temperature on battery
life.
> My batteries are cold most of the time, so I need the heat.
What does "cold" mean to you? If your batteries are 25C (room temp or
slightly above), then Hawker's literature indicates you are most likely
already getting all the capacity you can from them unless you are
discharging at very high rates.
> I'm not worried so much about range as I am about cycle life.
> I think the cycle life of an ACP car and the NREL tests are
> conclusive proof that controlled warmth is better.
The NREL tests have been discussed onlist in the past and are riddled
with problems that undermine their value. Yes, they suggest that there
may be value in further research, but their own conclusions are
questionable. For instance, they claim that their tests demonstrate a
dramatic increase in battery pack life using their charge regimen,
however, they kept replacing batteries as they failed throughout most of
the test duration so that in reality very few of the original batteries
actually survived the number of cycles that they claim for the "pack".
What is the cycle life of the ACP car? How many cycles, to what DOD?
So far you have referred to a single data point, something like 30k mi
from their pack, however, since their car gets at least 2x the mi per Wh
as yours, this translates to something less than 15000mi in your case.
ACP monitored each battery individually; your system did/does not; how
much of the difference in battery life is attibutable to better BMS and
charging?
The typical reason for heating batteries is to increase range per
charge, something that is/was arguably more important to ACP for
marketing reasons than battery pack life.
As an example, Al Godfrey managed to accumulate over 1200 cycles on his
144V stack of buddy-paired YTs. He used a Zivan charger and Rudman
regs; he did *not* operate the batteries at an elevated temperature. He
limited DOD to 50% or less whenever possible. Let's assume he got an
average of 10mi per charge: this is 12000mi from his pack (and it was
still usable at 1200 cycles, but he sold the car at that point so we
don't know how many more it might have accumulated). I don't know the
Wh/mi of his 914, but 250Wh/mi is probably not an unreasonable ballpark:
so his battery life translates to 20000mi at ACP's 150Wh/mi. With a
better charger and BMS it is compeletely believable that he could have
matched ACP's performance *without* operating the pack at an elevated
temperature.
> Are you arguing for the sake of debate Roger?
Absolutely not! The topic of battery charging is near and dear to my
heart, and I am simply trying to ensure that if you decide to proceed
with operating your pack at elevated temperatures you do so with the
benefit of having considered all available information. While I would
be most interested in the outcome of your experiment, I would hate for
you to kill an expensive pack of AGMs prematurely.
Good luck to you, and please share your observations with the rest of
us!
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Danny Miller wrote:
Should have sprung for the Deluxe package, which comes with a driver's
side floor standard.
... the salesman tried to pressure me into getting the solid floor, but
I stood firm at my budget limit of $75 for the whole vehicle with the
"oxidization package". ;-)
- darin
--- End Message ---
--- Begin Message ---
In a message dated 4/5/06 3:16:54 PM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
<< Who is CE? What model charger are you looking at?
Mike
>>
--- End Message ---
--- Begin Message ---
In a message dated 4/5/06 3:16:54 PM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
<< Who is CE? What model charger are you looking at?
Mike >>
I am sorry CE is my 8 second qt.mile electric dragster the Current
Eliminator.I have been using the 10 packx3 deltran charger for thousands of
hours.It is
offboard so I will also use it to balance the 26ah hawkers in my new S10
Street/Drag truck.(the one that will run 10s by the third try) Dennis Berube
--- End Message ---
--- Begin Message ---
Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
> 150 wh/mi is at very low speed on level ground. It's not
> what a typical user generates in daily driving. This is
> what I have observed riding in these cars.
So which "cars" are you referring to? Alan's original (and only?) CRX
running Optimas or one or more Tzero's running Optimas? I thought there
were only a couple Tzeros built and that at least one of them is running
a near-7000 cell Li pack, not lead-acid.
If 150Wh/mi is not typical, what have you observed to be typical in
these cars?
> These are the weekly clues I get that tell me ACP's
> battery management has great merit in making battery
> life all it can be.
I'm a great believer in BMS. You have provided nothing to suggest to me
that heating the batteries does anything to improve battery life in a
cyclic application. My belief is that those who operate their batteries
at elevated temperatures do so to achieve the absolute greatest range
per charge, and that a good BMS may allow them to still achieve a decent
life *despite* the detrimental effects of elevated temperature on the
battery internals.
> I'd like to see what lead acid Ranger and EV1 owners use to get from a
> pack in terms of cycle life.
There is no such thing as an EV1 owner; EV1's were leased, and I doubt
anyone will ever know what the true battery life was since the factory
service could include anything from swapping out weak modules before the
leasee ever noticed them to swapping out the entire pack, without the
user being any the wiser.
> What kind of EV do you own Roger?
Not sure why that is relevant, but mine is a 120V Suzuki Forsa (Chevy
Sprint) conversion presently loaded with YTs. I suppose I should be
cheering you on to go ahead and cook a set of YTs so the rest of us can
learn on your dime what to do with our packs ;^>, but I can't help but
caution you when everything we know about lead acid batteries suggests
that elevated temperatures are at odds with maximising battery life.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Mark Freidberg [mailto:[EMAIL PROTECTED] wrote:
> Roger Stockton <[EMAIL PROTECTED]> wrote:
> You
> *must* observe their caution against the use of washers
> between the cables and the battery terminal if you use the
> 3/8" studs (the batteries I have have both 3/8" studs and SAE posts).
>
> What is the caution? Why not use washers?
Discover's caution is simply "do not use washers between the cables and
battery terminals", and they believe strongly enough in its importance
to have put a label to this effect on the top of each battery as a
reminder.
The problem is that the steel, perhaps stainless, washer is a very poor
electrical conductor and results in a voltage drop and heat generation.
In theory the material that the fastener (the threaded post in this
case) is made of is irrelevant since its job is merely to hold the cable
end/lug against the battery terminal; it does not actually conduct a
significant fraction of the load current. However, if one places a
steel washer between the lug and terminal, the connection between the
lug and terminal becomes poor enough that a significant portion of the
load current may flow through the fastener (the rest of it flows through
the similarly poorly conducting washer). The result can be enough heat
generation to actually melt the battery case around the terminal!
For some reason, Discover includes a pair of flat washers, a lock
washer, and a nut for each threaded post in the little hardware bag that
comes with each battery. The junior technician who wired up my test
pack for me dutifully used up all the supplied hardware, installing a
flat washer on each side of the cable lugs! I didn't discover this at
first, only finding it when I discovered a battery connection that was
too hot to touch after 1hr at 75A, but was clean and tight. After I
inspected and removed the extra flat washers, not only did all the
connections run nice and cool, but the odd slight voltage difference
between modules that had been suggestive of some SOC/capacity imbalance
disappeared (the modules were actually quite well balanced).
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
I would really like to get 80 miles in the Porsche 911 and I could fit
26 110ah AGM batteries inside.
Looks like 8 in the gas tank area, 6 across the back seat, 2 on the
floor and 10 in the engine compartment.
The battery weight would be 27x72lbs=1944lbs. I think the awesome
porsche handling will go out the window with a final weight over
3800lbs. I'm now thinking of the small light pickup instead. The extra
weight should be easier to deal with.
Any Porsche experts out there? I hate to sell this car.
-Robert
Cor van de Water wrote:
Hi Robert,
Yeah, I was positively surprised with this range.
The airo-mods will have their impact, but I would
not dare to guess how much.
"Hearsay" suggestes that you can improve 10 - 20%
the other 80% difference between a 150 Wh/mi car and
my truck is probably the doubled weight and all the
consequences thereof and the frontal area that is
traditionally one of the issues of a truck.
(Even in this truck I feel the sideways sweep from
a large SUV or truck passing me in the next lane.
They are litterally pushing against the wind,
instead of cutting through it.)
I heard that removal of the tail gate or even a tonneau
can worsen the airodynamics, iso improving it.
The bed is an almost undisturbed air bubble (fallen leaves
stay in the bed for weeks of driving around at highway speed)
If you would find a compact built car that can handle the
weight of my pack (and I think you are on the right track
with a Porsche) then you should be able to achieve below
200 Wh/mi consumption mainly from airodynamic improvements.
Keeping your speed limited (difficult in a Porsche!)
should give you about 100 miles of range without killing
your pack (80% DOD, not empty).
So, your attempted 80 miles range is still doable, though
you may want to think about battery heaters to keep them
above 60 deg in winter, otherwise you may not make it when
you start with a cold car.
Note that battery heating can be connected to the charger
input, running from the grid, as the batteries should
survive the hour in the cold when you insulate them.
Since you do not intend to race, the heat production should
not be a large concern.
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Robert Baertsch
Sent: Tuesday, April 04, 2006 1:27 PM
To: [email protected]
Subject: Re: How many amps driving my EV?
Cor,
Thanks for the data, 55 miles is impressive in a vehicle of that size.
The difference in drain between 55 and 68 mph is surprising.
How much do you think you can improve your range by doing aerodynamic
changes?
For example,
bed pan underneath to improve air flow.
removing tail gate
custom shaped rear shell.
-Robert
Cor van de Water wrote:
(In the spirit of sharing actual driving consumption to
help battery sizing - I get many questions like that)
My vehicle:
I have a 1994 Chevy S-10 (light truck)
US Electricar conversion, see also:
http://autos.groups.yahoo.com/group/uselectricar/
and I measured the amps while doing
constant speed on the Freeway.
(higher tire pressure and a break-in
period have reduced amps from previous runs)
NOTE: it was drizzling during this trip,
which may result in slightly lower tire friction.
Driving down Freeway 101 at 56 MPH:
55 - 60Amp at 312V
(306 - 334 WattHour/mile)
Going to max throttle, reaching 68 MPH:
100 - 110Amp. (almost twice the power!)
(450 - 500 Wh/mile)
I'll stay with 55-60 MPH whenever I can.
(Taking off uses 140 - 200Amp and reaching
55 - 60 MPH in this 5000 lbs truck takes
about 30 - 40 seconds. Not fast but adequate
and I can keep up with most traffic but the
gas guzzlers. Suits me perfectly.)
BTW - Last Saturday I beat my previous max distance
on one charge by going 55 miles and still having 315V
resting voltage (12.1V per battery)
I did notice my acceleration was more limited in the end,
the controller has a configurable low voltage limit, which
is set to 273V (10.5V per battery) and it will cut output
when this limit is reached, so I will be unable to kill
my batteries as long as they stay balanced.
I was able to maintain speed, but hard acceleration quickly
resulted in jerking, a sign of reaching the limit, so it
took longer to get up to speed.
My estimation is that I was down to 30-35% SOC, based on
the numbers for the resting voltage and the approximately
1 Ah per mile (312V pack) of this truck.
Note: this pack has 110Ah batteries, 1 hour rating is 80Ah
so 65-70% of that is 52-56 Ah.
Note2: I still have the idea that my battery wiring has more
series resistance than the internal resistance of the
batteries, which means that the 273V limit is NOT 10.5V at
the battery, dependent on the current.
I need to measure the difference as I suspect the wiring,
connectors and contactor to add too many milliOhms, so the
batteries actually need to supply more current than when
the resistance is lower (more volts => more power =>
shorter acceleration OR I can trade the higher volts for
lower amps to get the same accel). I may also gain range by
reducing this 'waste' and avoid problems with overheating
cabling. (most is only 2 AWG)
(My voltage/current measurement make me believe that the
internal resistance as seen by the controller is almost
300 milliOhm while the batteries are specified at 4 mOhm,
so the 26 in series should only contribute 104 milliOhm.
Unless the time it takes to go from acceleration to braking
and back to acceleration also allows the batteries to have
internal changes in electrolyte (stratification problem in
AGMs? Lee?)
But since I see a discrepancy of some 196 milliOhms, I want
to check the connections at the controller; the contactor;
the wiring to the battery box and my own wiring inside the
battery box, although I believe that should contribute less
than 50 milliOhm according my own measurements while doing
the installation of the batteries.
One check point can be to bring one battery's actual
voltage out and measure it with a DVM while doing a launch
and see how far it drops.
Then do a measurement of the voltage across the entire
battery pack, then the voltage across the contactor and
cabling....
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
--- End Message ---
--- Begin Message ---
Hi Mike,
I did not know Saturn makes trucks. Which model?
This was not round-trip (that's why I made the comment about wind)
my evening commute is usually in rush-hour, so no way to get
a stable reading like rolling to work halfway the morning
(after the early morning teleconference)
I won't try to do 52 MPH in the carpool lane, unless the driver(s)
in front of me do the same.
Regards,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Mike Phillips
Sent: Wednesday, April 05, 2006 1:43 PM
To: Cor van de Water
Subject: Re: How many amps driving my EV?
What was the average for both directions? Eddies Saturn gets 157
WH/mile best case. So we have a ways to go.
Mike
--- In [EMAIL PROTECTED], Cor van de Water <[EMAIL PROTECTED]> wrote:
>
> Another datapoint,
> it looks like the road-users are helping me to get measurements.
> Today traffic was slow, but rather constant, so I could follow
> traffic and do 52 MPH most of the route on 101.
>
> I admit that there was a light breeze "in the back" and as
> usual, no height differences.
>
> I was amazed when inspecting the V/A logs of my controller
> where I found almost all current around 40 Amp at 320V,
> which means I used only 12.8kW to drive down the
> freeway at 52 MPH in this truck!
> That is under 250Wh/mi and in line with the efficiency
> that Mike reported. Wow.
>
> Cor van de Water
> Systems Architect
> Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Proxim Wireless Networks eFAX: +1-610-423-5743
> Take your network further http://www.proxim.com
>
>
> -----Original Message-----
> From: Cor van de Water
> Sent: Tuesday, April 04, 2006 3:46 PM
> To: '[EMAIL PROTECTED]'
> Subject: RE: How many amps driving my EV?
>
>
> Mike,
>
> I know - I should get an Emeter. Too many thing to do right
> now, so I go by with the data reported from my controller
> once per second and averaging it over a long trip
> (more than 5 miles of freeway 101, all just above Bay level,
> so I am sure there are no height differences!)
>
> Only factor I did not compensate for was wind, but I checked
> that there was no significant storm (trees did not move).
>
> 260 Wh/mi is amazingly efficient.
> It will be difficult to do long distance 45 MPH for me, this
> speed is not in my commute.
>
> Cor van de Water
> Systems Architect
> Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Proxim Wireless Networks eFAX: +1-610-423-5743
> Take your network further http://www.proxim.com
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Mike Phillips
> Sent: Tuesday, April 04, 2006 7:38 AM
> To: [EMAIL PROTECTED]
> Subject: Re: How many amps driving my EV?
>
>
> Hi Cor,
>
> Some tips. An Emeter would greatly assist in understanding the real
> numbers your truck generates. The other thing that was learned is that
> a no load measurement of the pack can mislead you greatly. A couple of
> us now use 60 amps as the load used for comparing data between our
> vehicles. I know the voltage discharge curve is linear, but believing
> that will bite you.
>
> Any incline or decline in the road surface makes a big difference in
> measuring WH/mile. What I do is go to a known destination, then
> backagain. That averages out the topology. The Emeter never lies. Yours
> eyes and assumptions will lie to you. I found this out when I got my
> Emeter working. It has educated me greatly. So has recording the data
> the truck generates on a laptop.
>
> My most efficient drive: On the slow drive from Mckee and Capitol, up
> 101 to 880 west. Then up Coleman to Costco. Costco's Avcon charger is
> not charging, although it is powered up. The round trip in afternoon
> rush hour gave me an average of 260 wh/mile. My truck has low rolling
> resistance tires rated 44 psi now at 50 psi. I can feel the difference
> over the old tires. Normal lead foot driving gives me 400-450 WH/mile
> in stop and go traffic.
>
> Before I changed the Emeter over to WH/mile it would read AH/mile. The
> average was 1 AH per mile. .9 AH on the expressways at 45 mph.
>
> Mike
>
>
>
>
>
>
>
>
> --- Cor van de Water <[EMAIL PROTECTED]> wrote:
>
> > (In the spirit of sharing actual driving consumption to
> > help battery sizing - I get many questions like that)
> > My vehicle:
> > I have a 1994 Chevy S-10 (light truck)
> > US Electricar conversion, see also:
> > http://autos.groups.yahoo.com/group/uselectricar/
> > and I measured the amps while doing
> > constant speed on the Freeway.
> > (higher tire pressure and a break-in
> > period have reduced amps from previous runs)
> > NOTE: it was drizzling during this trip,
> > which may result in slightly lower tire friction.
> >
> > Driving down Freeway 101 at 56 MPH:
> > 55 - 60Amp at 312V
> > (306 - 334 WattHour/mile)
> >
> > Going to max throttle, reaching 68 MPH:
> > 100 - 110Amp. (almost twice the power!)
> > (450 - 500 Wh/mile)
> >
> > I'll stay with 55-60 MPH whenever I can.
> >
> > (Taking off uses 140 - 200Amp and reaching
> > 55 - 60 MPH in this 5000 lbs truck takes
> > about 30 - 40 seconds. Not fast but adequate
> > and I can keep up with most traffic but the
> > gas guzzlers. Suits me perfectly.)
> >
> > BTW - Last Saturday I beat my previous max distance
> > on one charge by going 55 miles and still having 315V
> > resting voltage (12.1V per battery)
> > I did notice my acceleration was more limited in the end,
> > the controller has a configurable low voltage limit, which
> > is set to 273V (10.5V per battery) and it will cut output
> > when this limit is reached, so I will be unable to kill
> > my batteries as long as they stay balanced.
> > I was able to maintain speed, but hard acceleration quickly
> > resulted in jerking, a sign of reaching the limit, so it
> > took longer to get up to speed.
> > My estimation is that I was down to 30-35% SOC, based on
> > the numbers for the resting voltage and the approximately
> > 1 Ah per mile (312V pack) of this truck.
> >
> > Note: this pack has 110Ah batteries, 1 hour rating is 80Ah
> > so 65-70% of that is 52-56 Ah.
> >
> > Note2: I still have the idea that my battery wiring has more
> > series resistance than the internal resistance of the
> > batteries, which means that the 273V limit is NOT 10.5V at
> > the battery, dependent on the current.
> > I need to measure the difference as I suspect the wiring,
> > connectors and contactor to add too many milliOhms, so the
> > batteries actually need to supply more current than when
> > the resistance is lower (more volts => more power =>
> > shorter acceleration OR I can trade the higher volts for
> > lower amps to get the same accel). I may also gain range by
> > reducing this 'waste' and avoid problems with overheating
> > cabling. (most is only 2 AWG)
> > (My voltage/current measurement make me believe that the
> > internal resistance as seen by the controller is almost
> > 300 milliOhm while the batteries are specified at 4 mOhm,
> > so the 26 in series should only contribute 104 milliOhm.
> > Unless the time it takes to go from acceleration to braking
> > and back to acceleration also allows the batteries to have
> > internal changes in electrolyte (stratification problem in
> > AGMs? Lee?)
> > But since I see a discrepancy of some 196 milliOhms, I want
> > to check the connections at the controller; the contactor;
> > the wiring to the battery box and my own wiring inside the
> > battery box, although I believe that should contribute less
> > than 50 milliOhm according my own measurements while doing
> > the installation of the batteries.
> >
> > One check point can be to bring one battery's actual
> > voltage out and measure it with a DVM while doing a launch
> > and see how far it drops.
> > Then do a measurement of the voltage across the entire
> > battery pack, then the voltage across the contactor and
> > cabling....
> >
> > Regards,
> >
> > Cor van de Water
> > Systems Architect
> > Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> > Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> > Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> > Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> > Proxim Wireless Networks eFAX: +1-610-423-5743
> > Take your network further http://www.proxim.com
> >
> >
>
>
> Here's to the crazy ones.
> The misfits.
> The rebels.
> The troublemakers.
> The round pegs in the square holes.
> The ones who see things differently
> The ones that change the world!!
>
> www.RotorDesign.com
>
--- End Message ---
--- Begin Message ---
There may be more, but ACP had Alan's orginal CRX with batterys inside
the car like most converted ev's. Then they built at least two more
Hondas. One of which is a CRX the other is just slightly larger but
still a two door version. Then there is the Saturn as well. I've lost
track of the Tzeros as most have been sold. They still had a lead acid
car down there. I know one Lion Tzero car that is up here around
Silicon Valley somewhere.
Typical is 220 wh/mi with no kindness to acceleration. I promise this
is a 14 second car.
If heating was not germaine to the packs life, ACP would not have kept
putting it in their lead acid cars.
One of the ACP owner/drivers doesn't watch for DOD at all. He drives
his car until the monitoring system shows 11 volts per battery under
light load. Which is about 40-50 amps in these cars. He gets 20-30k
from a pack in his daily driver. He has told me that getting 20-30k is
routine in their cars.
These guys plus the NREL report are enough proof for me to investigate
and build thermal management into my truck. Maybe having Optimas is
the magic ingredient, but I have to do something constructive as 5k
miles per pack makes a 440 powered Chrysler look cheap to drive. That
is providing that I don't sell the truck first ;)
Mike
--- In [EMAIL PROTECTED], "Roger Stockton" <[EMAIL PROTECTED]> wrote:
>
> Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
>
> > 150 wh/mi is at very low speed on level ground. It's not
> > what a typical user generates in daily driving. This is
> > what I have observed riding in these cars.
>
> So which "cars" are you referring to? Alan's original (and only?) CRX
> running Optimas or one or more Tzero's running Optimas? I thought there
> were only a couple Tzeros built and that at least one of them is running
> a near-7000 cell Li pack, not lead-acid.
>
> If 150Wh/mi is not typical, what have you observed to be typical in
> these cars?
>
> > These are the weekly clues I get that tell me ACP's
> > battery management has great merit in making battery
> > life all it can be.
>
> I'm a great believer in BMS. You have provided nothing to suggest to me
> that heating the batteries does anything to improve battery life in a
> cyclic application. My belief is that those who operate their batteries
> at elevated temperatures do so to achieve the absolute greatest range
> per charge, and that a good BMS may allow them to still achieve a decent
> life *despite* the detrimental effects of elevated temperature on the
> battery internals.
>
> > I'd like to see what lead acid Ranger and EV1 owners use to get from a
> > pack in terms of cycle life.
>
> There is no such thing as an EV1 owner; EV1's were leased, and I doubt
> anyone will ever know what the true battery life was since the factory
> service could include anything from swapping out weak modules before the
> leasee ever noticed them to swapping out the entire pack, without the
> user being any the wiser.
>
> > What kind of EV do you own Roger?
>
> Not sure why that is relevant, but mine is a 120V Suzuki Forsa (Chevy
> Sprint) conversion presently loaded with YTs. I suppose I should be
> cheering you on to go ahead and cook a set of YTs so the rest of us can
> learn on your dime what to do with our packs ;^>, but I can't help but
> caution you when everything we know about lead acid batteries suggests
> that elevated temperatures are at odds with maximising battery life.
>
> Cheers,
>
> Roger.
>
--- End Message ---
--- Begin Message ---
My comment about the Saturn is that our trucks are very inefficient
compared other AC systems on the road. I get poked in the ribs about
this every day.
Coming home the other direction at any speed/traffic is still
relevent. Average both directions and see what you get.
Mike
--- In [EMAIL PROTECTED], Cor van de Water <[EMAIL PROTECTED]> wrote:
>
> Hi Mike,
>
> I did not know Saturn makes trucks. Which model?
>
> This was not round-trip (that's why I made the comment about wind)
> my evening commute is usually in rush-hour, so no way to get
> a stable reading like rolling to work halfway the morning
> (after the early morning teleconference)
>
> I won't try to do 52 MPH in the carpool lane, unless the driver(s)
> in front of me do the same.
>
> Regards,
>
> Cor van de Water
> Systems Architect
> Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Proxim Wireless Networks eFAX: +1-610-423-5743
> Take your network further http://www.proxim.com
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Mike Phillips
> Sent: Wednesday, April 05, 2006 1:43 PM
> To: Cor van de Water
> Subject: Re: How many amps driving my EV?
>
>
> What was the average for both directions? Eddies Saturn gets 157
> WH/mile best case. So we have a ways to go.
>
> Mike
>
>
>
> --- In [EMAIL PROTECTED], Cor van de Water <ev@> wrote:
> >
> > Another datapoint,
> > it looks like the road-users are helping me to get measurements.
> > Today traffic was slow, but rather constant, so I could follow
> > traffic and do 52 MPH most of the route on 101.
> >
> > I admit that there was a light breeze "in the back" and as
> > usual, no height differences.
> >
> > I was amazed when inspecting the V/A logs of my controller
> > where I found almost all current around 40 Amp at 320V,
> > which means I used only 12.8kW to drive down the
> > freeway at 52 MPH in this truck!
> > That is under 250Wh/mi and in line with the efficiency
> > that Mike reported. Wow.
> >
> > Cor van de Water
> > Systems Architect
> > Email: CWater@ Private: http://www.cvandewater.com
> > Skype: cor_van_de_water IM: cor_van_de_water@
> > Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> > Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> > Proxim Wireless Networks eFAX: +1-610-423-5743
> > Take your network further http://www.proxim.com
> >
> >
> > -----Original Message-----
> > From: Cor van de Water
> > Sent: Tuesday, April 04, 2006 3:46 PM
> > To: 'ev@'
> > Subject: RE: How many amps driving my EV?
> >
> >
> > Mike,
> >
> > I know - I should get an Emeter. Too many thing to do right
> > now, so I go by with the data reported from my controller
> > once per second and averaging it over a long trip
> > (more than 5 miles of freeway 101, all just above Bay level,
> > so I am sure there are no height differences!)
> >
> > Only factor I did not compensate for was wind, but I checked
> > that there was no significant storm (trees did not move).
> >
> > 260 Wh/mi is amazingly efficient.
> > It will be difficult to do long distance 45 MPH for me, this
> > speed is not in my commute.
> >
> > Cor van de Water
> > Systems Architect
> > Email: CWater@ Private: http://www.cvandewater.com
> > Skype: cor_van_de_water IM: cor_van_de_water@
> > Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> > Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> > Proxim Wireless Networks eFAX: +1-610-423-5743
> > Take your network further http://www.proxim.com
> >
> >
> > -----Original Message-----
> > From: owner-ev@ [mailto:[EMAIL PROTECTED]
> > Behalf Of Mike Phillips
> > Sent: Tuesday, April 04, 2006 7:38 AM
> > To: ev@
> > Subject: Re: How many amps driving my EV?
> >
> >
> > Hi Cor,
> >
> > Some tips. An Emeter would greatly assist in understanding the real
> > numbers your truck generates. The other thing that was learned is that
> > a no load measurement of the pack can mislead you greatly. A couple of
> > us now use 60 amps as the load used for comparing data between our
> > vehicles. I know the voltage discharge curve is linear, but believing
> > that will bite you.
> >
> > Any incline or decline in the road surface makes a big difference in
> > measuring WH/mile. What I do is go to a known destination, then
> > backagain. That averages out the topology. The Emeter never lies.
Yours
> > eyes and assumptions will lie to you. I found this out when I got my
> > Emeter working. It has educated me greatly. So has recording the data
> > the truck generates on a laptop.
> >
> > My most efficient drive: On the slow drive from Mckee and Capitol, up
> > 101 to 880 west. Then up Coleman to Costco. Costco's Avcon charger is
> > not charging, although it is powered up. The round trip in afternoon
> > rush hour gave me an average of 260 wh/mile. My truck has low rolling
> > resistance tires rated 44 psi now at 50 psi. I can feel the difference
> > over the old tires. Normal lead foot driving gives me 400-450 WH/mile
> > in stop and go traffic.
> >
> > Before I changed the Emeter over to WH/mile it would read AH/mile. The
> > average was 1 AH per mile. .9 AH on the expressways at 45 mph.
> >
> > Mike
> >
> >
> >
> >
> >
> >
> >
> >
> > --- Cor van de Water <CWater@> wrote:
> >
> > > (In the spirit of sharing actual driving consumption to
> > > help battery sizing - I get many questions like that)
> > > My vehicle:
> > > I have a 1994 Chevy S-10 (light truck)
> > > US Electricar conversion, see also:
> > > http://autos.groups.yahoo.com/group/uselectricar/
> > > and I measured the amps while doing
> > > constant speed on the Freeway.
> > > (higher tire pressure and a break-in
> > > period have reduced amps from previous runs)
> > > NOTE: it was drizzling during this trip,
> > > which may result in slightly lower tire friction.
> > >
> > > Driving down Freeway 101 at 56 MPH:
> > > 55 - 60Amp at 312V
> > > (306 - 334 WattHour/mile)
> > >
> > > Going to max throttle, reaching 68 MPH:
> > > 100 - 110Amp. (almost twice the power!)
> > > (450 - 500 Wh/mile)
> > >
> > > I'll stay with 55-60 MPH whenever I can.
> > >
> > > (Taking off uses 140 - 200Amp and reaching
> > > 55 - 60 MPH in this 5000 lbs truck takes
> > > about 30 - 40 seconds. Not fast but adequate
> > > and I can keep up with most traffic but the
> > > gas guzzlers. Suits me perfectly.)
> > >
> > > BTW - Last Saturday I beat my previous max distance
> > > on one charge by going 55 miles and still having 315V
> > > resting voltage (12.1V per battery)
> > > I did notice my acceleration was more limited in the end,
> > > the controller has a configurable low voltage limit, which
> > > is set to 273V (10.5V per battery) and it will cut output
> > > when this limit is reached, so I will be unable to kill
> > > my batteries as long as they stay balanced.
> > > I was able to maintain speed, but hard acceleration quickly
> > > resulted in jerking, a sign of reaching the limit, so it
> > > took longer to get up to speed.
> > > My estimation is that I was down to 30-35% SOC, based on
> > > the numbers for the resting voltage and the approximately
> > > 1 Ah per mile (312V pack) of this truck.
> > >
> > > Note: this pack has 110Ah batteries, 1 hour rating is 80Ah
> > > so 65-70% of that is 52-56 Ah.
> > >
> > > Note2: I still have the idea that my battery wiring has more
> > > series resistance than the internal resistance of the
> > > batteries, which means that the 273V limit is NOT 10.5V at
> > > the battery, dependent on the current.
> > > I need to measure the difference as I suspect the wiring,
> > > connectors and contactor to add too many milliOhms, so the
> > > batteries actually need to supply more current than when
> > > the resistance is lower (more volts => more power =>
> > > shorter acceleration OR I can trade the higher volts for
> > > lower amps to get the same accel). I may also gain range by
> > > reducing this 'waste' and avoid problems with overheating
> > > cabling. (most is only 2 AWG)
> > > (My voltage/current measurement make me believe that the
> > > internal resistance as seen by the controller is almost
> > > 300 milliOhm while the batteries are specified at 4 mOhm,
> > > so the 26 in series should only contribute 104 milliOhm.
> > > Unless the time it takes to go from acceleration to braking
> > > and back to acceleration also allows the batteries to have
> > > internal changes in electrolyte (stratification problem in
> > > AGMs? Lee?)
> > > But since I see a discrepancy of some 196 milliOhms, I want
> > > to check the connections at the controller; the contactor;
> > > the wiring to the battery box and my own wiring inside the
> > > battery box, although I believe that should contribute less
> > > than 50 milliOhm according my own measurements while doing
> > > the installation of the batteries.
> > >
> > > One check point can be to bring one battery's actual
> > > voltage out and measure it with a DVM while doing a launch
> > > and see how far it drops.
> > > Then do a measurement of the voltage across the entire
> > > battery pack, then the voltage across the contactor and
> > > cabling....
> > >
> > > Regards,
> > >
> > > Cor van de Water
> > > Systems Architect
> > > Email: CWater@ Private: http://www.cvandewater.com
> > > Skype: cor_van_de_water IM: cor_van_de_water@
> > > Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> > > Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> > > Proxim Wireless Networks eFAX: +1-610-423-5743
> > > Take your network further http://www.proxim.com
> > >
> > >
> >
> >
> > Here's to the crazy ones.
> > The misfits.
> > The rebels.
> > The troublemakers.
> > The round pegs in the square holes.
> > The ones who see things differently
> > The ones that change the world!!
> >
> > www.RotorDesign.com
> >
>
--- End Message ---
--- Begin Message ---
Yet moer instrumentation...
If a battery gets to the point of boiling/gassing, you should be able
to hear it right? How about a sonic detector running through a
comparator to turn on an LED or something to let the driver know the
battery is hot inside enough to boil electrolyte?
I've heard car batterys boiling after a massive overcharge, but not
VRLM's. Can you in fact hear it?
Mike
--- End Message ---
--- Begin Message ---
Thanks, that clarifies it:
"Make sure battery terminal and cable terminal are in direct contact"
(and maximize the contact area by cleaning / flattening)
I have seen many warped lugs and dirty battery terminals
even after cleaning them, a washer is introducing yet an
additional transition that adds resistance.
My batteries also came with stainless steel bolts, nuts,
flat and split washers (battery has two Flag-terminals)
So all that needs to be done is put the bolt through the
cable terminal first, without washer (since this is the
harder material) then through the battery terminal, add
the flat washer, add the split washer and then torque the
nut onto this.
If you have only a bolt (battery has screw hole) then
you start with a split washer on the bolt, flat washer,
then the cable terminal and then bolt it into the hole.
In case you want to re-use existing cables:
MAKE SURE to measure each one of them for resistance.
I had a bunch of cables, some from Ebay, some already in
the truck before I started installing batteries.
Most of them had a resistance of well below 1 milliOhm,
but there were 2 cables that either were badly crimped
or the lug was oxidized inside, because there was a large
resistance between lug and cable.
I would have cooked one battery terminal off the battery
that would have gotten that cable installed, so I cut
the offending lug and installed a new (with NOALOX).
Most of my battery-cable connections are not crimped but
clamped, using a bronze grounding attachment that has a
cable hole for a 2/0 cable and a flat mounting area with
hole. Area surface is about 1 square inch, so good contact
almost guaranteed after lightly filing to achieve a
shiny surface and a light touch of NOALOX to avoid the
contact to deteriorate from oxidation.
Since most batteries are inaccessible, it will be hard
to re-torque them, therefor I wanted the contact to
remain good even at low contact pressure (after the lead
has deformed due to the pressure)
I checked contact resistance after finger-tightening one
battery contact and it was perfect, could not reduce it
by bolting it down (well below 0.1 milliOhm)
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Roger Stockton
Sent: Wednesday, April 05, 2006 4:05 PM
To: [email protected]
Subject: RE: Would like large AGM with good EV user history
Mark Freidberg [mailto:[EMAIL PROTECTED] wrote:
> Roger Stockton <[EMAIL PROTECTED]> wrote:
> You
> *must* observe their caution against the use of washers
> between the cables and the battery terminal if you use the
> 3/8" studs (the batteries I have have both 3/8" studs and SAE posts).
>
> What is the caution? Why not use washers?
Discover's caution is simply "do not use washers between the cables and
battery terminals", and they believe strongly enough in its importance
to have put a label to this effect on the top of each battery as a
reminder.
The problem is that the steel, perhaps stainless, washer is a very poor
electrical conductor and results in a voltage drop and heat generation.
In theory the material that the fastener (the threaded post in this
case) is made of is irrelevant since its job is merely to hold the cable
end/lug against the battery terminal; it does not actually conduct a
significant fraction of the load current. However, if one places a
steel washer between the lug and terminal, the connection between the
lug and terminal becomes poor enough that a significant portion of the
load current may flow through the fastener (the rest of it flows through
the similarly poorly conducting washer). The result can be enough heat
generation to actually melt the battery case around the terminal!
For some reason, Discover includes a pair of flat washers, a lock
washer, and a nut for each threaded post in the little hardware bag that
comes with each battery. The junior technician who wired up my test
pack for me dutifully used up all the supplied hardware, installing a
flat washer on each side of the cable lugs! I didn't discover this at
first, only finding it when I discovered a battery connection that was
too hot to touch after 1hr at 75A, but was clean and tight. After I
inspected and removed the extra flat washers, not only did all the
connections run nice and cool, but the odd slight voltage difference
between modules that had been suggestive of some SOC/capacity imbalance
disappeared (the modules were actually quite well balanced).
Cheers,
Roger.
--- End Message ---
