[ausev] Fwd: Good sources to get started?

[Roy Holder]

At 10:37 AM 11/28/2007 -0600, you wrote:
>On Wed, 2007-11-28 at 09:34 -0600, Roy Holder wrote:
>> 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.
>
>I hate to be pedantic, but I feel it's important to risk being a pest
>especially for newcomers to understand the units we use.
snip
>
>"Amp-hours per mile" is one way to express this value, but you need the
>pack voltage for it to be useful, as Roy has provided. In general it's
>easier to quote watt-hours per mile instead which incorporates both
>these values, and which is the standard in EV conversations. Assuming
>100Ah and 120V, this gives a total of 12kWh in the pack. With a 40 mile
>range this works out to 300Wh/mile, which is reasonable and in the
>middle of the range you typically see (200-400). Of course it also
>matches his first set of numbers, 2.5Ah/mile at 120V = 300Wh/mile.

yes, but 1 amp per mile per 1000 lbs at 120v is a calculation you can
easily do in your head.

>
>I am curious about the stated 1-hour rate however. If accurate you're
>definitely getting a lot more out of them than the usual calculation (20
>hour advertised rate * .57) would suggest. Very cool if so; it may be
>due to the non-continuous nature of driving...  (?)

The calculation you are refering to is called Peukert's Law, and it is
actually different for every battery.  My batteries are Trojan 150's, I
used a web page to calc peukerts ration based on the manufacturers specs.
It actually calcs out to about 105 ah at the 1 hour rate.  I have taken the
batts to 97 amps once and 80 to 85 amps three other times in the 18 months
I have had them. 

>
>
>-- 
>Christopher Robison
>chris at ohmbre.org
>http://ohmbre.org          <-- 1999 Isuzu Hombre + Z2K + Warp13!
>
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