RE: A 48 volt Freeway EV?

["Scudder, Henry J" <Henry.Scudder@West.Boeing.com>]

Jay
	My Tropica uses 72v, no gearing, two motors, top speed about 62mph.
However it pulls 600 A or more climbing hills, which is a major source of
problems such as battery terminal melting, fires, etc. It would be a much
better car with a higher voltage and a transmission, even a two speed one.

Hank

> ----------
> From: 	Wilson, John A[SMTP:John.Wilson5@PSS.Boeing.com]
> Reply To: 	ev@listproc.sjsu.edu
> Sent: 	Wednesday, June 30, 1999 2:10 PM
> To: 	'Post a message to EV list'
> Subject: 	A 48 volt Freeway EV?
> 
> Just another philosophical ramble on EV design... there's been a tendency
> in EV design to go to higher and higher voltages in the battery pack. This
> is great for performance, but also increases the problems with batteries.
> The more cells, the more problems with equalization, cell failures...most
> problems with hobbyist EVs are caused by the batteries.
> 
> Perhaps the ultimate design for a day-to-day commuter (not a dragster) EV
> would be to go to less voltage.  A 48 volt EV could use the massive Trojan
> L16 batteries, which will last twice as long as the toughest golf cart
> batteries, judging from the experience from off grid "Home Power"
> applications. How about 40,000 miles on a set of batteries!  Fewer,
> larger, and tougher cells makes for a highly reliable battery pack.  And
> maintenance problems would be reduced as well. Watering the few cells in a
> 48 v pack would be easy,  and also infrequent because of the huge water
> capacity of the cells.  Another benefit is that the shock hazard would be
> almost eliminated at 48v.
> 
> The obvious problem would be performance, if one's objective is to build a
> real car, not a golf cart. Today's high power controllers can handle the
> 1000 amps required to give a 48 volt EV good acceleration and freeway
> speed. However, a specially designed motor may also be needed , one with
> but fewer but heaver windings and some sort of super-heavy duty
> commutator.
> 
> Could a 48v freeway-capable EV be built?
> 
> --Jay Wilson
> 
> Seattle
> Jay  Wilson
> 737 ECS Air Distribution & E/E Cooling
> 425-237-0269  MS 70-04
> Fax 425-237-6149
>