[ausev] Open Garage this Sat... 9am - 1pm
Roy Holder
roy at holder3.com
Thu Aug 20 20:36:16 GMT 2009
At 03:13 PM 8/20/2009 -0500, you wrote:
>9000 cycles? Or 900 cycles?
900, 9k is LOT!
>
>-----Original Message-----
>From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
>Behalf Of Roy Holder
>Sent: Thursday, August 20, 2009 10:58 AM
>To: AustinEV News Announcements and General Discussion
>Subject: Re: [ausev] Open Garage this Sat... 9am - 1pm
>
>Mark,
>
>I have gotten 3 years and 15,000 miles out of my trojan J150 batteries.
>Since early this summer I can no longer make a round trip to work and home,
>but I can charge at work, so they are still 'usable'. One charge a work
>day most of the year(250) and 2 a day for Dec-Mar, means nearly 9000
>cycles. The batteries are heating up more now during charging and venting
>a little acid. Im holding off replacing them to see if LiFe drops some
>more... Keeping my fingers crossed.
>
>I draw around 100 to 180 amps from the batteries during my trips, up to 300
>for brief acceleration on to 183. Car would hold 60 mph up and down hills
>on north 183 untill revently, now it drops to just under 55 up the great
>hills overpass. I still only use about 40-42 amps a day from the
>batts(averaged 270 watthour/Mile). Max ah used during a range test was 95
>when the batts were about a month old. The geo is about 2800 lbs with the
>batts. About 40% overall average depth of discharge,
>
>I dont have a 25 amp load to test the batts with, so I cant compare to
>published data.
>
>This is all DC efficiency metering, I have an inductive clamp AC amp
>meter, I should make a power cord one of these days before I replace the
>batteries to see what the AC efficiency is.........before and after.
>
>how is your daily draw vs capacity?
>
>At 11:08 AM 8/13/2009 -0500, you wrote:
>>Great stuff Brian.
>>This is good info to know as it’s the true picture of the efficiency of the
>>system.
>>We often only focus on DC efficiency, i.e. efficiency of the car that moves
>>the vehicle a certain distance for a given amount of available energy. For
>>example to estimate the range of a small vehicle with 10kWh of usable
>>energy, one could assume an average of 250Wh/mile efficiency (or "fuel
>>economy") which would give it a 40 mile range (+/-). But we don't often
>>talk about the system efficiency, which includes battery efficiency and
>>charger efficiency and any parasitic loads on the car while charging
>>(cooling pumps for example). I think the Tesla claims a 350Wh/mile
>>efficiency number taking into account all of these things. Flooded lead
>>acids are less efficient than li-ion, for one reason, because they require
>>an overcharge for balancing which eats into efficiency.
>>
>>So by that metric, your fuel economy/efficiency has been:
>>Feb 389 wh/mile
>>March 455
>>April 543
>>May 592
>>June 1230
>>July 874
>>
>>We can assume that the efficiency of the charger is relatively the same
>>throughout the year, but battery round trip efficiency does change with
>>temperature, cycle life, and age. It appears your batteries are now using
>>twice the energy from the wall to give you the same mileage. Because the
>>chemistry of the battery is changing for reasons previously listed, one
>>would need a charging system that would adapt as well. Using the simple
>>"charge to X volts" doesn't really work (from an efficiency point of view)
>>after the battery has been sufficiently used. I bet some amount of
>>overcharge could be eliminated by a charging algorithm that stopped
>charging
>>due to different criteria than just voltage and range would still not be
>>diminished.
>>
>>Don't get me wrong, I think the PFC charger is an amazing piece of
>>equipment, very versatile and powerful. It's just hard to have a the
>>knowledge of how best to charge a battery as it ages/cycles/temperature as
>>even the manufacturers are still learning. As you can imagine, not much
>>research was performed to determine optimal end of life charging criteria
>>for golf cart batteries. Now that EVs are being developed by OEMs, that
>>work is being done and hopefully those lessons, algorithms, and equipment
>>will trickle down for the hobbyist.
>>
>>Brian, what batteries are you going to replace them with? Same ones or
>>something different?
>>How many cycles are on them?
>>What is the average depth of discharge?
>>Perhaps you could discharge one at 25A and compare it to published data to
>>see where it falls on the graph.
>>Marc Kohler
>>
>>-----Original Message-----
>>From: ausev-bounces at austinev.org [mailto:ausev-bounces at austinev.org] On
>>Behalf Of Brian Lasseter
>>Sent: Thursday, August 13, 2009 10:00 AM
>>To: AustinEV News Announcements and General Discussion
>>Subject: [ausev] Open Garage this Sat... 9am - 1pm
>>
>>I have used and abused my batteries every day for the past 15
>>months... and it is time for some new batteries.
>>
>>So, I will be holding an open garage this Sat for anyone who wants to
>>help me remove batteries, anyone who wants to inspect my car closely,
>>or even anyone who wants to just sit in a chair and laugh as I lift
>>70lb batteries. :-) All comers welcome.
>>
>>@ Lasso's House : (512) 736-1677
>>Saturday, August 15th : 9am - 1pm
>>11402 B Ptarmigan Cove
>>Austin, TX 78758
>>
>>
>>--
>>
>>
>>If you are wondering WHY I am replacing the pack, I seem to have been
>>slowly melting a battery post over the last few weeks, and it finally
>>started dripping lead last weekend. Really though, the whole pack is
>>becoming unworkable. The range is still a good 30 miles, but the heat
>>generated keeps my pack at a fairly constant 140°F - 150°F which is
>>making it difficult for even the water miser caps to retain water.
>>I've also noticed that the heat is really killing my electrical
>>efficiency, and preventing me from getting anywhere near the correct
>>charging voltage. At 140°F charging temperature, then 174vdc would be
>>the manufacturer's recommended charging voltage... but that was rarely
>>reached.
>>
>>For anyone interested in numbers... here are my efficiency numbers for
>>the last few months of driving, and the total over the life of the
>>battery pack. Efficiency has units of miles/kwh. I'm not sure if
>>anyone else has any insight as to whether 6206 miles or 3882kwh is a
>>good run for a lead battery pack?
>>
>>
>> kwh end miles end kwh miles
>>efficiency
>>
>> Jan 15456 149605
>> Feb 15669 150152 213 547 2.568075117
>> Mar 15869 150592 200 440 2.2
>> Apr 16045 150916 176 324 1.840909091
>> May 16242 151249 197 333 1.69035533
>> June 16579 151523 337 274 0.81305638
>> July 17080 152096 501 573 1.143712575
>>
>>
>>
>> 13270 145953
>> Total 17152 152159 3882 6206 1.598660484
>>
>>--
>>TTFN,
>>Brian "Lasso" Lasseter
>>
>> · (512)736-1677 · AIM:digininja · ICQ:2238123 · MSN:azoreg ·
>>"No Sane man will dance." -Cicero (106-43 B.C.)
>>
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