RE: EV Grin Returns

["Todd Hunter" <hunter@progressivesystems.com>]

Lee,

	Just read your message about the losses in controllers and batteries due to
ripple in current.  Isn't there a way to engineer the controllers to cut
these losses, or has it just never been an issue?

 I have an old (very old... dinosaur) controller from the Jet Electric cars,
gray box that whistles loudly.   I am adding batteries to my 96V VW Pickup
to go up to 108V-120V and will be buying a new controller.  Haven't decided
yet what to get but right now my acceleration sucks and I would to buy one
that is more efficient as well.


Todd Hunter



-----Original Message-----
From: owner-ev@listproc.sjsu.edu [mailto:owner-ev@listproc.sjsu.edu]On
Behalf Of Lee Hart
Sent: Wednesday, February 28, 2001 3:13 PM
To: ev@listproc.sjsu.edu
Subject: Re: EV Grin Returns

Rod.Hower@ametek.com wrote:
> The problem with the Curtis was not just efficiency (which I can only
> guess is only 2% or so better on the DCP).

The efficiency of a PWM controller is tricky to measure. If you measure
just the controller itself, it will be in the high 90's. But, the ripple
current it causes in the batteries and motor cause additional losses.
Though these are hard to measure and thus usually ignored, they are
actually larger than controller losses. My guess would be 2% loss in the
controller itself, and another 2-5% loss each in the motor and
controller.
--
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen