EV Digest 5322
Topics covered in this issue include:
1) Re: How many amps driving my EV?
by "Mike Phillips" <[EMAIL PROTECTED]>
2) Re: Battery Pack Heating
by "Mike Phillips" <[EMAIL PROTECTED]>
3) Re: Battery Pack Heating
by "Mike Phillips" <[EMAIL PROTECTED]>
4) RE: Battery Pack Heating - Optima Hawker links
by "Roger Stockton" <[EMAIL PROTECTED]>
5) Re: Battery Pack Heating
by "Mike Phillips" <[EMAIL PROTECTED]>
6) RE: Multi charger.
by [EMAIL PROTECTED]
7) RE: Battery Pack Heating
by [EMAIL PROTECTED]
8) Re: Dual Motors to FWD axles
by [EMAIL PROTECTED]
9) Re: '74 MG electric on eBay
by [EMAIL PROTECTED]
10) Re: Thanks for all the insight on my project
by Danny Miller <[EMAIL PROTECTED]>
11) Re: Dual Motors to FWD axles
by Andrew Letton <[EMAIL PROTECTED]>
12) 1209 or 1221B parts
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
13) RE: Battery Pack Heating
by "Roger Stockton" <[EMAIL PROTECTED]>
14) Re: Battery Pack Heating - Optima Hawker links
by "Mike Phillips" <[EMAIL PROTECTED]>
15) Re: Multi charger.
by [EMAIL PROTECTED]
16) RE: Battery Pack Heating
by "Roger Stockton" <[EMAIL PROTECTED]>
17) Re: Battery Pack Heating
by "Mike Phillips" <[EMAIL PROTECTED]>
--- Begin Message ---
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 ---
Right, and my projected range keeps them under the max temp ratings.
After following the work of AC Propulsion, I will attempt to duplicate
the thermal/voltage monitoring and control of my pack(s) just has they
have. Their work produces 20-30k miles from a set of Optimas. Their
cars can charge up to around 30 amps into the pack and draw up to 450
amps during discharge. It's a 100kw system. I'm sure the one ACP car
can do 14 second 1/4 miles. Packs lasting that long must have a reason
why they endure so well. My truck can only charge at 6.5 amps and
discharge at 200 amps, yet the pack is nearly dead at 5k miles. Same
experience with other USE vehicle owners. The death also has to do
with having far to many batterys at a very small capacity to start
with. So it was a setup for failure from the start. My Emeter shows my
average trips to be 20 AH or about 20 miles. Still didn't help them
last in California weather.
The pro's show through published data that warm batterys last longer.
Many of you are familiar with the work of the NREL lab. They published
these articles showing what can be done to extend the life of Optimas
specifically. Although some of their testing was extreme.
www.nrel.gov/vehiclesandfuels/energystorage/pdfs/evs_17paper.pdf
www.nrel.gov/vehiclesandfuels/energystorage/pdfs/evs17pres.pdf
ACP does not publish a huge amount of technical data. But they do tell
about how long their packs last in their cars. I am fortunate to know
these guys enough to ask them the questions needed to help me
understand what works and what does not when it comes to lead acid
batterys. I consider these guys to very credible.
Mike
--- In [EMAIL PROTECTED], Cor van de Water <[EMAIL PROTECTED]> wrote:
>
> Mike,
>
> These are MAX temperatures.
> NOT to be crossed without derating (reducing amps).
> You always need to adapt volts to changing temps, no matter
> at which temp you started or ended.
> The East-Penn battery book link that was shared recently
> had some nice graphs and tables about battery voltage/temp.
>
> You better stay below the max temps if you want max performance
> and long battery life.
>
> In San Jose you better think about battery cooling than heating.
>
> If your batteries are below freezing a significant part of the year
> and you need range, then battery heating is in order.
> I am also near San Jose and I have not heated my batteries and
> I also do not intend to add battery heating.
>
> Why do you think that heating might improve your EV (more than a
> few percent in range)?
>
> 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 9:39 AM
> To: Ralph Merwin
> Subject: Re: Battery Pack Heating
>
>
> Here are some VRLA manufacturer's temperature maximums for cyclic use.
>
> BB Battery 35c
> Optima 51.7c (AC Propulsion keeps them at 30c-40c)
> Hawker Genesis 45c
>
> All of the graphs that I see show that the voltage needs to be
> controlled at higher temps or it can hurt a battery. I can do this
> with clampers.
>
> Roland: Were the burn marks on the battery or on the round cable? Were
> these 5 watts/foot that you tried?
>
> Michaela: Using a thermostat is a good idea.
>
> Here in San Jose there are almost no heaters to speak of as I ran
> around yesterday and looked all over town. So if you guys have some
> URL's to share, that would be helpful.
>
> Mike
>
>
>
>
> --- In [EMAIL PROTECTED], Ralph Merwin <ev@> wrote:
> >
> >
> > Mike,
> >
> > I'm using thin stick-on heaters that Metric Mind used to carry. I
have
> > one on the bottom of each battery, 26 in all. The heaters are rated
> > for 12v/36w each, but I run them in 13 sets of two heaters in series,
> > so they're putting out about 9 watts each. My heater controller
is set
> > for about 78 degrees F (about 26 C), with the temperature sensor
on the
> > bottom of the middle battery in each box. The boxes are insulated on
> > the bottom with rigid foam wall insulation (about 1/2" thick) and
on all
> > sides and the top with 1/2" expanded polyethylene.
> >
> > It takes a couple of days for the batteries to come up to temp, but I
> > leave the heater controllers on all the time.
> >
> > Dave Cloud uses 'garden bed heater wire'. You can buy these in
> pre-built
> > lengths with temperature sensor. Just plug them into a standard
120vac
> > outlet. You can put them under your batteries by cutting channels
into
> > sheets of insulation that the batteries rest on.
> >
> > Al Godfrey in Vancouver, BC uses battery heating blankets from JC
> Whitney.
> > These are interesting because they also have insulation.
> >
> > I think you should lower your temperature target. 40C is too hot.
> >
> > Ralph
> >
> >
> > Mike Phillips writes:
> > >
> > > I need suggestions for a heating system for my pack. I would like to
> > > use the orange silicone sheets, but they are hard to find in any
> length
> > > and are pricey. There are these home gutter or pipe heating cables
> that
> > > look good. They are around 5 watts per foot in 120vac or 240vac
> > > versions.
> > >
> > > The only car I know that has a heated pack runs about 500-600
> watts for
> > > the 1200lb pack. So that's about 2 lbs per watt. It takes most of 25
> > > hours to get the pack to the 30c-40c range. The system can hold it
> > > there with ease. It's usually heating during charging, but can be
> > > turned on any time.
> > >
> > > So I need ideas for how to heat this pack, and where to get the
> > > materials.
> > >
> > > Thanks,
> > >
> > > Mike
> > >
> > >
> > >
> > > 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 ---
I need the pack to achieve thermal equalibrium in 24 hours. I suspect
that's why ACP has 500 watts heating their packs up. The mass of the
battery pack will effect the rate of thermal change, that's why I need
a higher capacity cooling and heating system in my truck to get the
changes needed under control relatively quickly to maximize pack
longevity. From what I've seen so far it's not hard to build a system
that can make changes inside 24 hours.
Mike
--- In [EMAIL PROTECTED], Lee Hart <[EMAIL PROTECTED]> wrote:
>
> Mike Phillips wrote:
> > The pack is 2 Optimas tall by 14 by Optimas long. It sits in a box.
> > There is a some 1/8" insualtion on the inside and the outside of the
> > box.
>
> Ok; that's not much insulation. It's like heating a home with no
> insulation; it takes far more energy. You can still do it if you don't
> mind the cost of energy.
>
> > Plus the exterior of the box is inside the car.
>
> That helps if the car is in the sun. But car bodies have negligible
> insulation, too.
>
> > So 60w can bring the whole pack from 70f to 100f?
> > In how much time and at what ambient?
>
> Yes; I had measured 30 deg.F to 60 deg.F this last winter. It takes 2-3
> days.
>
> > How much is the total weight of your pack Lee?
>
> Two packs of six 63 lb batteries each, i.e. 120 watts for 756 lbs of
> batteries.
>
> I think a key point is that the *weight* of the batteries is
> unimportant; all that matters is the thermal resistance (insulation) of
> the box they are in. It wouldn't make any difference whether the battery
> box was empty or full; all that matters is the surface area and
> insulation of the walls. An empty box would heat up much faster, but
> takes the same number of watts to maintain temperature.
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in -- Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>
--- End Message ---
--- Begin Message ---
Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
> Here is the link for the Optimas.
> http://www.optimabatteries.com/publish/optima/americas0/en/con
> fig/product_info/automotive/deep_cycle/technical_specs.html
The proper interpretation is the 51.7C (125F) max temperature spec in this
document is that charging must not be allowed to continue if the battery
temperature exceeds this point. Nowhere does Optima recommend operating their
product at this temperature.
> Here is the link for the Hawker brochure download. Page 4, 6
> are noteworthy.
> http://www.enersysreservepower.com/documents/US-GPL-AM-002_0605.pdf
I'd say there's interesting stuff on page 5 too:
Page 4:
- calendar (float) life is 10yrs @ 25C (not 20C as I misremembered)
- operating temp range is -40C to +45C (which is not the same as saying life
and performance will be equal anywhere within this range, but simply that use
*outside* this range is to be avoided)
"In general, if the battery is to be discharged frequently,
cycle life rather than calendar life is more relevant."
[Assuming proper, temperature compensated charging!]
Page 5:
"While several factors affect the life of a battery, cycle life
depends primarily on the depth of discharge (DOD)."
"In contrast to cycle life, ambient temperature dramatically
affects float life. For roughly every 8°C rise in ambient
temperature above 25ºC (77ºF), the float life of a VRLA
battery is cut in half. In other words, a 10-year battery at
25°C (77°F) is only a 5-year battery at 33°C (91°F). Additionally,
float life is cut in half for every 100mV per cell over the
recommended float charge voltage."
[The effect of incorrectly temperature compensated charge voltages on battery
life is implied here.]
Page 5:
The effect of temperature on battery capacity is illustrated. Notice that the
effect increases as the rate of discharge increases, but even at the 15min (4C)
rate, there is only a 10% increase in capacity when the batteries are operated
at 40C vs 25C. At lower rates, such as 1C, there is a negligible (ie. none
visible) increase in capacity associated with heating the battery above 25C.
Further:
"Although the Genesis battery may be used, with appropriate
derating, from -40°C (-40°F) to 80°C (176°F), it is strongly
recommended that every effort be made to install them in
temperature-regulated environments. Metal jackets are
required for temperatures exceeding 45°C (113°F) continuous.
All battery temperatures refer to the temperatures
experienced by the active materials inside the battery."
In short, Hawker is telling you that there is no capacity benefit associated
with operating their batteries above 25C unless you are discharging them *very*
rapidly, and that while DOD will likely have the greatest impact on battery
life in a cyclic application, we know that operating the batteries at elevated
temperatures *will* shorten their lives further.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
My truck can only charge at 6.5 amps and discharge at 200 amps. They
just don't get that warm. That's part of the reason I need to get a
thermal management system going. If heating a pack for a 100-150Kw
system works well, then it has to improve my 50kw system.
I hear what you are saying, but have any of these battery vendors
shown you data to back up their words? I've been through the verbal
references in so many hobbies and sports that I only look for data
now. There is just so much hearsay spoken as evidence.
The other thing is that Optimas may have a better ability to work in a
high temp environement compared to other VRLA brands. That may be part
of what I need to find out as I do the research.
Mike
--- In [EMAIL PROTECTED], "Roger Stockton" <[EMAIL PROTECTED]> wrote:
>
> Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
>
> > Here are some VRLA manufacturer's temperature maximums for cyclic use.
> >
> > BB Battery 35c
> > Optima 51.7c (AC Propulsion keeps them at 30c-40c)
> > Hawker Genesis 45c
>
> These are *NOT* recommended temperatures for use; these are typical
> "stop charging or discharging immediately if the battery exceeds this
> level" temperatures.
>
> Optima is notoriously bad at providing useful literature for their
> batteries, but Hawker does provide decent literature. You should read
> it sometime. Battery life, etc. is quoted assuming an operating
> temperature of 20C and *HALVES* for every 10 degree rise above that
> point. This is known widely as the Arrhenius (possibly misspelled ;^)
> relationship, and applies to *all* lead acid batteries.
>
> At least one VRLA manufacturer has told me that if the battery is over
> 40C there is no point in worrying too greatly about temperature
> compensation of the voltage because the battery is being killed anyway.
> That is, no matter how ideally you treat it otherwise, it will still die
> prematurely.
>
> A flooded battery manufacturer has told me they get concerned about
> reduced battery life if the electrolyte temperature exceeds 80F during
> charge, especially if there is not an adequate coolling off period
> betweeen the end of charge and start of discharge.
>
> Most manufacturers recommend halting charging immediately if the battery
> temp exceeds some level. 50C (120F) is pretty common. I think I saw a
> value of 55C for Optimas once upon a time.
>
> Heat your batteries to 30-40C if you are racing or want to get the
> absolute maximum capacity from them (but, again, read Hawker's
> literature - they have graphs of capcity vs temperature and you can see
> that it is a matter of diminishing returns to heat them much above
> 25-30C). Operating them at this level *will* shorten their life, though
> you may not actually notice much degradation unless you had the charging
> etc. just right (that is, you won't get rated life unless you treat them
> right in every other regard, so whether they die prematurely due to
> mistreatment or to being run too hot, they still die prematurely).
>
> > All of the graphs that I see show that the voltage needs to
> > be controlled at higher temps or it can hurt a battery. I can
> > do this with clampers.
>
> I doubt that. You need to temperature compensate the absorption
> voltage, and at the start of the absorption phase you are typically
> still running full bulk current. The current drops off as the batteries
> fill up, but it spends most of the absorption phase *well* above the
> couple of amps that most clampers can survive for any length of time.
>
> Don't forget also that discharging the batteries causes them to heat up,
> and charging them also causes them to heat up. If you are holding them
> at 30-40C (surface temp), they will be hotter than this inside, which is
> what counts. Your heating system can't actively cool them to maintain
> 30-40C, so you have very little room for temperature rise associated
> with normal use. If the batteries are at 30-40C (surface temp) at the
> start of charge, and heat up from there, and then you rely on
> dissipative clampers to provide voltage compensation, you better have
> the clamper loads out of the battery box so they aren't also dumping
> their heat into the batteries...
>
> Good luck,
>
> Roger.
>
--- End Message ---
--- Begin Message ---
<<< I'm sorry, but how could it possibly cost several thousand bux to install a
simple 240v line? I installed my own in my garage for less than $50. All you
need is an open breaker lug in the service panel and some wire and a receptacle.
>>>
Haven't got a garage, and don't touch the breaker box except to reset one of
them, so I took the quote from a local electrician as "average market value"
for the 240V/50A line required by Avcon (even though the Ford never pulls more
than 30A from it) with outdoor housing. Being someone who'd never want a bank
of meters and switches in my EV, I'll also leave playing with the AC line
alone.
--- End Message ---
--- Begin Message ---
<<< These are *NOT* recommended temperatures for use; these are typical
"stop charging or discharging immediately if the battery exceeds this
level" temperatures.
Optima is notoriously bad at providing useful literature for their
batteries, but Hawker does provide decent literature. You should read
it sometime. Battery life, etc. is quoted assuming an operating
temperature of 20C and *HALVES* for every 10 degree rise above that
point. This is known widely as the Arrhenius (possibly misspelled ;^)
relationship, and applies to *all* lead acid batteries.
At least one VRLA manufacturer has told me that if the battery is over
40C there is no point in worrying too greatly about temperature
compensation of the voltage because the battery is being killed anyway.
That is, no matter how ideally you treat it otherwise, it will still die
prematurely. >>>
Wow! So I guess folks in hot desert areas either don't go electric or spend a
lot on AC for the pack -- when more than half a summer day is over 104F (40C),
that might suck up a lot of kwh just in cooling. We have August nights that
don't get below 70, and that's in NorCal - imagine the lifespan of a pack in
AZ, NM or the Mojave!
--- End Message ---
--- Begin Message ---
<<< Currently driving a 48 Volt 90 Geo Metro with E-volks kit and
alltrax.
Have been offered a 96 metro 4 door automatic with no eng or trans
so I am looking at doing another low budget /low speed city car.
Looking for a simple way to put an electric motor/motors in it .....>>>
Somehow, I think trying to mount motors and their individual reduction gearing
to each CV would be both more complicated *and* more expensive than just
mounting a new tranny with one motor.
--- End Message ---
--- Begin Message ---
<<< I pray they don't junk that car I'd even pitch in for storage for a few
months
till someone took it if it meant keeping it out of the crusher. >>>
The seller is suppose to be the grandson of the original owner - if so, he would
never think of "junking" the car! But it does make Neon John's point about the
market for EVs - Blue Sky Motors isn't getting the reserve price on their
Rangers, even the NiMH one.
--- End Message ---
--- Begin Message ---
Should have sprung for the Deluxe package, which comes with a driver's
side floor standard.
Danny
Darin wrote:
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 ---
I'd have to agree.
Metro manual transmissions are $65 at my local salvage yard...and there
are many to choose from...
cheers,
Andrew
[EMAIL PROTECTED] wrote:
<<< Currently driving a 48 Volt 90 Geo Metro with E-volks kit and
alltrax.
Have been offered a 96 metro 4 door automatic with no eng or trans
so I am looking at doing another low budget /low speed city car.
Looking for a simple way to put an electric motor/motors in it .....>>>
Somehow, I think trying to mount motors and their individual reduction gearing
to each CV would be both more complicated *and* more expensive than just
mounting a new tranny with one motor.
--- End Message ---
--- Begin Message ---
I need front end cards, cases, power sections etc for Curtis controllers
36-48v and up. Working or not but not totally destroyed. . Contact me off
list please. If anyone is aware of Curtis parts suppliers with excess stock
please let me know or if anyone working at Curtis has an idea what will
happen to all their stock please let me know. I heard the Curtis
controllers are not being serviced by Curtis now & may not be produced
anymore..
Lawrence Rhodes
Bassoon/Contrabassoon
Reedmaker
Book 4/5 doubler
Electric Vehicle & Solar Power Advocate
Vegetable Oil Car.
415-821-3519
[EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
> My truck can only charge at 6.5 amps and discharge at 200
> amps. They just don't get that warm.
You'd be surprised. At the end of charge much of the charge energy is
going into heat, and while it may take some time for you to sense this
at the surface of the battery case, the internal temp of the battery may
easily rise 10 degrees even though the charge rate is quite low.
> If heating a pack for a 100-150Kw system works well, then
> it has to improve my 50kw system.
No, actually, it doesn't! Read the Hawker literature you refer to; the
capacity vs temperature characteristics they document clearly show that
a higher power system (read higher discharge rate) will benefit more
from elevated battery temperatures than will a low power system.
ACP may have gotten 30k miles from a set of Optimas, but that is
meaningless without more data to back it up. If my commute is 20mi,
then the set of Optimas is useless to me once the capacity drops such
that I cannot make a minimum of 20mi per charge. If I can do usefull
things with the EV even when the range has dropped to 5mi, then I can
clearly get more cycles and miles of life from the same pack.
ACP's CRX was a far more efficient vehicle than most, something like
150Wh/mi as I recall. This means that they could get as much as 2x the
miles per cycle as many conversions. 25 YTs at about 40Ah and 12V
nominal is 12kWh of storage; at 150Wh/mi this is about 80mi/cycle or
only 375 cycles to achieve 30000mi. The impressive part is the 80mi
range, not the 375 cycle life. Conversely, YTs are purported to have an
exponentially increasing cycle life with decreasing DOD; we can find a
point on the curve where lifetime energy throughput is maximised, lets
say 20% DOD. If 20% DOD yields a range sufficient satisfy my needs,
perhaps I end up with a 30000mi lifetime (especially since the pack
remains usable until it has less than 20% capacity left). This is not
the result if battery heating or another silver bullet, it is simply a
fact of life that I will get more miles from my pack than the guy who
has to discharge to 80%DOD for his daily commute, even if we both treat
our packs identically otherwise. And an EV that gets 100Wh/mi will
obviously get more miles from a given pack than one that gets 300Wh/mi.
> I hear what you are saying, but have any of these battery
> vendors shown you data to back up their words?
I don't generally deal with battery vendors; I deal with the battery
manufacturer's technical experts as my day job involves developing
charge algorithms for their batteries. Unfortunately, I am not
generally in a position to share the information that battery
manufacturers share with me, but I encourage you to contact the
manufacturer of your batteries directly and see what information they
are willing to share with you.
> The other thing is that Optimas may have a better ability to
> work in a high temp environement compared to other VRLA
> brands.
Perhaps, but I suspect chemistry is chemistry: the rate of reaction
increases with temperature, so grid corrosion and all the other nasty
undesirable stuff is going to occur more rapidly at elevated
temperatures than at room temperature.
More likely, perhaps, is that Optimas exhibit a stronger relationship
between capacity and temperature, such that heating them to 30-40C
results in a greater increase in capacity, and therefore a decrease in
DOD for the same Ah removed. If you cycle the batteries often enough,
the increase in cycle life associated with shallower DOD may translate
into getting more miles onto the pack before it dies than if you cycled
it less frequently at the same elevated temperature, or cycled it as
frequently at a lower temperature.
Anyway, good luck in your experimentation; I'm sure the list will
welcome more real data to base their own decisions on!
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Roger,
>> The proper interpretation is the 51.7C (125F) max temperature spec
in this document is that charging must not be allowed to continue if
the battery temperature exceeds this point. Nowhere does Optima
recommend operating their product at this temperature.
>>
I'm operating in a temperature range that makes this point mute.
As for float life, I don't see how it applies to EV's. 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. Let me be clear. My
batteries are cold most of the time, so I need the heat.
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.
Are you arguing for the sake of debate Roger?
Mike
>
> > Here is the link for the Hawker brochure download. Page 4, 6
> > are noteworthy.
> > http://www.enersysreservepower.com/documents/US-GPL-AM-002_0605.pdf
>
> I'd say there's interesting stuff on page 5 too:
>
> Page 4:
>
> - calendar (float) life is 10yrs @ 25C (not 20C as I misremembered)
> - operating temp range is -40C to +45C (which is not the same as
saying life and performance will be equal anywhere within this range,
but simply that use *outside* this range is to be avoided)
>
> "In general, if the battery is to be discharged frequently,
> cycle life rather than calendar life is more relevant."
> [Assuming proper, temperature compensated charging!]
>
> Page 5:
>
> "While several factors affect the life of a battery, cycle life
> depends primarily on the depth of discharge (DOD)."
>
> "In contrast to cycle life, ambient temperature dramatically
> affects float life. For roughly every 8°C rise in ambient
> temperature above 25ºC (77ºF), the float life of a VRLA
> battery is cut in half. In other words, a 10-year battery at
> 25°C (77°F) is only a 5-year battery at 33°C (91°F). Additionally,
> float life is cut in half for every 100mV per cell over the
> recommended float charge voltage."
>
> [The effect of incorrectly temperature compensated charge voltages
on battery life is implied here.]
>
> Page 5:
>
> The effect of temperature on battery capacity is illustrated.
Notice that the effect increases as the rate of discharge increases,
but even at the 15min (4C) rate, there is only a 10% increase in
capacity when the batteries are operated at 40C vs 25C. At lower
rates, such as 1C, there is a negligible (ie. none visible) increase
in capacity associated with heating the battery above 25C.
>
> Further:
>
> "Although the Genesis battery may be used, with appropriate
> derating, from -40°C (-40°F) to 80°C (176°F), it is strongly
> recommended that every effort be made to install them in
> temperature-regulated environments. Metal jackets are
> required for temperatures exceeding 45°C (113°F) continuous.
> All battery temperatures refer to the temperatures
> experienced by the active materials inside the battery."
>
> In short, Hawker is telling you that there is no capacity benefit
associated with operating their batteries above 25C unless you are
discharging them *very* rapidly, and that while DOD will likely have
the greatest impact on battery life in a cyclic application, we know
that operating the batteries at elevated temperatures *will* shorten
their lives further.
>
> Cheers,
>
> Roger.
>
--- End Message ---
--- Begin Message ---
In a message dated 4/5/06 11:11:36 AM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
<< Subj: Re: Multi charger.
Date: 4/5/06 11:11:36 AM Pacific Daylight Time
From: [EMAIL PROTECTED] (Rich Rudman)
Sender: [EMAIL PROTECTED]
Reply-to: [email protected]
To: [email protected]
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, April 04, 2006 3:43 PM
Subject: Re: Multi charger.
> In a message dated 4/4/06 11:00:23 AM Pacific Daylight Time,
>
> Rich Rudman
> Manzanita Micro
> >>
> Rich do not forget I also use modular chargers,Thats why I got 375 cycles
on
> the Inspira battery while others were getting 10-20 cycles. Dennis Berube
>
I clearly said there were exceptions.
Your Race car application...is a little off the topic of On road daily
drivers that need to be qiuck charged.
You can 't get those cards any more, and ... the general public would have
to spend a fortune to get those cards from you and then set them up.
Rich Rudman
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 ---
[EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] wrote:
> Wow! So I guess folks in hot desert areas either don't go
> electric or spend a lot on AC for the pack -- when more than
> half a summer day is over 104F (40C), that might suck up a
> lot of kwh just in cooling. We have August nights that don't
> get below 70, and that's in NorCal - imagine the lifespan of
> a pack in AZ, NM or the Mojave!
There is no doubt that batteries provide a shorter service life in these
areas, but bear in mind that the drastic shortening of life with
temperature is going to be most evident in standby or float (UPS-type)
applications. In cyclic use the effect of elevated temperature on the
battery life will probably be less apparent since the battery life will
be shortened by other factors (DOD, sub-optimal charging, etc.) to an
even greater extent. ;^>
This, to me, is one of the great attractions of the Zebra battery; it
operates at such an elevated temperature that the thermal management is
quite simple: no matter where on the globe you are, you will always only
ever need a battery heating system (and it is built in). The hotter
your local climate, the less energy the battery needs to consume
maintaining operating temperature.
With lead-acid (and to a far greater extent, nickle-zinc, when they were
available), you may need heating in cool climates, cooling in hot
climates, and both depending on the time of year in other climates.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
ACP uses the Pomona loop just like Socal Edison. As usual for ACP they
define the extremes. 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.
They don't generally dabble in 20% DOD. They also turn their vehicles
over to private parties for more real life testing. The private ACP
owners I know do not operate their vehicles at a 20% DOD or anything
close to it. In fact I see 70% DOD alot from their cars as I ride in
them. They also take great advantage of the acceleration. 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'd like to see what lead acid Ranger and EV1 owners use to get from a
pack in terms of cycle life.
What kind of EV do you own Roger?
Mike
--- In [EMAIL PROTECTED], "Roger Stockton" <[EMAIL PROTECTED]> wrote:
>
> Mike Phillips [mailto:[EMAIL PROTECTED] wrote:
>
> > My truck can only charge at 6.5 amps and discharge at 200
> > amps. They just don't get that warm.
>
> You'd be surprised. At the end of charge much of the charge energy is
> going into heat, and while it may take some time for you to sense this
> at the surface of the battery case, the internal temp of the battery may
> easily rise 10 degrees even though the charge rate is quite low.
>
> > If heating a pack for a 100-150Kw system works well, then
> > it has to improve my 50kw system.
>
> No, actually, it doesn't! Read the Hawker literature you refer to; the
> capacity vs temperature characteristics they document clearly show that
> a higher power system (read higher discharge rate) will benefit more
> from elevated battery temperatures than will a low power system.
>
> ACP may have gotten 30k miles from a set of Optimas, but that is
> meaningless without more data to back it up. If my commute is 20mi,
> then the set of Optimas is useless to me once the capacity drops such
> that I cannot make a minimum of 20mi per charge. If I can do usefull
> things with the EV even when the range has dropped to 5mi, then I can
> clearly get more cycles and miles of life from the same pack.
>
> ACP's CRX was a far more efficient vehicle than most, something like
> 150Wh/mi as I recall. This means that they could get as much as 2x the
> miles per cycle as many conversions. 25 YTs at about 40Ah and 12V
> nominal is 12kWh of storage; at 150Wh/mi this is about 80mi/cycle or
> only 375 cycles to achieve 30000mi. The impressive part is the 80mi
> range, not the 375 cycle life. Conversely, YTs are purported to have an
> exponentially increasing cycle life with decreasing DOD; we can find a
> point on the curve where lifetime energy throughput is maximised, lets
> say 20% DOD. If 20% DOD yields a range sufficient satisfy my needs,
> perhaps I end up with a 30000mi lifetime (especially since the pack
> remains usable until it has less than 20% capacity left). This is not
> the result if battery heating or another silver bullet, it is simply a
> fact of life that I will get more miles from my pack than the guy who
> has to discharge to 80%DOD for his daily commute, even if we both treat
> our packs identically otherwise. And an EV that gets 100Wh/mi will
> obviously get more miles from a given pack than one that gets 300Wh/mi.
>
> > I hear what you are saying, but have any of these battery
> > vendors shown you data to back up their words?
>
> I don't generally deal with battery vendors; I deal with the battery
> manufacturer's technical experts as my day job involves developing
> charge algorithms for their batteries. Unfortunately, I am not
> generally in a position to share the information that battery
> manufacturers share with me, but I encourage you to contact the
> manufacturer of your batteries directly and see what information they
> are willing to share with you.
>
> > The other thing is that Optimas may have a better ability to
> > work in a high temp environement compared to other VRLA
> > brands.
>
> Perhaps, but I suspect chemistry is chemistry: the rate of reaction
> increases with temperature, so grid corrosion and all the other nasty
> undesirable stuff is going to occur more rapidly at elevated
> temperatures than at room temperature.
>
> More likely, perhaps, is that Optimas exhibit a stronger relationship
> between capacity and temperature, such that heating them to 30-40C
> results in a greater increase in capacity, and therefore a decrease in
> DOD for the same Ah removed. If you cycle the batteries often enough,
> the increase in cycle life associated with shallower DOD may translate
> into getting more miles onto the pack before it dies than if you cycled
> it less frequently at the same elevated temperature, or cycled it as
> frequently at a lower temperature.
>
> Anyway, good luck in your experimentation; I'm sure the list will
> welcome more real data to base their own decisions on!
>
> Cheers,
>
> Roger.
>
--- End Message ---
