Re: ?over voltage battery pack?

[xgt@juno.com (George S. Tylinski)]

OK, now it's time for someone to design a clever little circuit that
clamps the effective throttle pot resistance when the average voltage @
the motor reaches a predetermined value. I coulda used something like
that with my XP-1263 / Grizzly / 180V pack...

George Tylinski


On Fri, 28 Aug 98 09:44:36 +0100 "paul.compton"
<paul.compton@bbsrc.ac.uk> writes:
>
>>If I ran my 48v motor, via a controller, from a 48  volt  pack so 
>>that it drew 100 amps it would be rough on the batteries.
>>However from a 72 volt pack, the current would be 66.6 amps, plus 
>>whatever the controller eats.  This would get more total usable 
>>energy out of each battery, plus include 2 more batteries for more 
>>range.
>>Is this a valid understanding and application of  the 
>>physics/chemistry involved? 
>>If so does the increase in battery efficiency offset the losses 
>>incurred with the controller running at approximately 60% pulse 
>>width?
>>Can todays controllers be run this way?
>>
>>
>>Michael Shipway
>
>
>The ammount of time an on-road EV controller spends at 100% duty cycle 
>is often
>overestimated. The use of a battery pack of higher voltage than the 
>motor
>rating has been advocated by many people. The motor need not ever 
>'see' full
>pack voltage, but even as the pack fades the full rated voltage will 
>still be
>available for the motor. As long as the motor is kept within its safe 
>operating
>rpm, and within its thermal limits (not too much current for too 
>long), and as
>long as there are no problems with commutation (not too much current 
>or too
>high an rpm), you can use any voltage you like.
>
>
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