[ausev] Fwd: Good sources to get started?

Wed Nov 28 15:34:34 GMT 2007

another way to look at it:
my car gets about 1 amp per mile per 1000 lbs at 120v in town.
2500 lb car, 150 ah batts(100 amps 1 hour rate) 120v = 40 niles

I have run the car at 96v, 108v and 120v for extended periods of time,
kept a log of miles and amps, and calculated the energy use.

any body else have enough info on their EV to see if it is similar?

At 10:57 PM 11/27/2007 -0600, you wrote:
>Yes, except you missed the conversion from the 20 hour rate to the 1
>hour rate, which makes the batteries act smaller than they are.
>
>A little background - batteries are rated for a certain number of amps
>for a certain amount of time. The energy stored in the battery is then
>Amps X Time. The faster you discharge the batteries, the less capacity
>they appear to have. EVs tend to discharge their batteries at a rate
>that averages out to about emptying them in an hour, or a 1 hour rate.
>A rough conversion factor to account for this is to multiply the total
>capacity at the 20 Hour rate by .57 to get the 1 hour rate. (I think
>this number is right! but I might be off)
>
>I think this tends to be conservative, but a good first guess.
>
>Erik
>
>On Nov 27, 2007 10:28 PM, Josh Handel <jhandel at ktomics.net> wrote:
>> I think I understand BUT I as much as I think I get it, I think I don't
>> :-P... So let me perpose an "example" of what I am hearning, and someone
can
>> correct (sumorized example below word example) :-P
>>
>> Lets say I start with 12, 12v Batterys all rated for 40ah (at 20 hours to
>> make the math easy) running in serial.
>>
>> If I understand you correctly, what I have is 144v rated at 40 amp
hours. OR
>> 5.76kWh's of battery. (stop me here if I am totally wrong here)..
>>
>> Now continuing on, I make a "perfect" car and it gets 28.8 wh/m at 60mph..
>> so if everything above is "correct" and I understand what you are saying
>> then I have would have a 200 mile range (5760 watt hours / 28.8 watts
>> hours).
>>
>> 12 - 12volt/40Ah batteries in serial = 144volts at 40Ahs = 5760 Wh
>>
>> 5760 wh (from above) / 28.8 wh (consumption per mile) = 200 miles
>>
>> (yes these are totally bogus numbers, but I wanted to get the
>> forumla/concept right first :-)..)
>>
>> So did I "get it" or am I completely wrong?
>>
>> Thanks
>> Josh "Not an EE" Handel
>>
>>
>>
>> On 11/27/07, Sarah & Erik <electricbasset at gmail.com> wrote:
>> > A well built EV will take less than 250 WH/mile, a more common number
>> > is probably higher than that, say 300-350. This is probably
>> > appropriate numbers for around town use. Depending on aerodynamics
>> > your highway energy consumption could be much higher, maybe twice that
>> > at 60 mph.
>> >
>> > To take a stab at whether lead acid batteries will work, look at the
>> > total capacity which will be given at the 20 Hour rate, and multiply
>> > by .57 to get how much energy you can count on at the 1 Hour rate.
>> > Generally with Lead acid, aim for 50-60 % discharge on your normal
>> > run. Sorry for the short email, feel free to ask questions if this
>> > doesn't make sense.
>> >
>> > Please feel free to pipe up if you think my numbers are bogus.
>> >
>> > Erik
>> >
>> > On Nov 27, 2007 9:28 AM, Josh Handel <jhandel at ktomics.net> wrote:
>> > >
>> > > (Sorry for the duplicate if this shows up twice, I sent the first one
>> from
>> > > the wrong address, and I figure MailMan will probably bounce it so I am
>> > > sending it again, this time from the right address)
>> > >
>> > >
>> > > Howdy all,
>> > >
>> > >    I'm just starting the "investigation" stage of making an ev
roadster.
>> The
>> > > goal would be to have something I could commute with (currently its
a 50
>> > > mile round trip from lake travis into town (so Hill country +
highway)..
>> The
>> > > idea I am playing with is building roadster based on a locost design.
>> If
>> > > you want to know what a locost sports car is just google locost :-P but
>> the
>> > > short description is its a lotus 7 clone that is home grown.
>> > >
>> > >  Anyways before I can go to far I need to find out more about using an
>> EV
>> > > power plant (transmission concerns, power needs, battery capacity,
>> etc..)
>> > > and while I can read lots of different websites (and have been for the
>> last
>> > > few weeks). I figured I would be better off dropping a line and seeing
>> what
>> > > "starter" sources you guys suggest.. (yes I have read austinEV's
getting
>> > > started and EV America's getting started and a few others as well..
What
>> Im
>> > > am looking for is more detail about calculating performance, range, and
>> > > power, motor requirements, etc...
>> > >
>> > > Thanks
>> > > Josh
>> > > _______________________________________________
>> > > AusEV mailing list
>> > > AusEV at austinev.org
>> > > http://www.austinev.org/mailman/listinfo/ausev
>> > >
>> > >
>> > _______________________________________________
>> > AusEV mailing list
>> > AusEV at austinev.org
>> > http://www.austinev.org/mailman/listinfo/ausev
>> >
>>
>>
>> _______________________________________________
>> AusEV mailing list
>> AusEV at austinev.org
>> http://www.austinev.org/mailman/listinfo/ausev
>>
>>
>_______________________________________________
>AusEV mailing list
>AusEV at austinev.org
>http://www.austinev.org/mailman/listinfo/ausev
>
>
>-- 
>No virus found in this incoming message.
>Checked by AVG Free Edition. 
>Version: 7.5.503 / Virus Database: 269.16.8/1153 - Release Date:
11/26/2007 9:08 PM
>
>