RE: (ET) Re: 48v E-trac ??

["Dave Barden" <daveb seanet com>]

Good points all.  So I could still leave it at 36volts and get something to
step down the 48volts or an inverter.  I don't have any accessories save 
the
mower, but I definetely wouldn't want to fry those motors!!

thanks.

-----Original Message-----
From: owner-elec-trak cosmos phy tufts edu
[mailto:owner-elec-trak cosmos phy tufts edu]On Behalf Of Jim Coate
Sent: Friday, July 06, 2001 9:29 PM
To: daveb seanet com; Elec-Trak List
Subject: (ET) Re: 48v E-trac ??


daveb seanet com wrote:
> Has anyone heard of anyone converting the E-trac to a 48volts by
> using 6 8v batteries??

I've thought about this, but ruled it out. The drive motor could
probably take it, giving a little more "performance" (9 mph instead of 7
mph top speed??).

However, everything else would run into problems. The 12 volt tap for
the headlights would now be 16 volts... nice bright lights until they
burn out. The 18 volt lift would be at 24 volts... maybe it would
actually have some oomph, until it also burned up.

All the accessories would also now be running at 48 volts. I think that
the snow blower and tiller motors are series or sep-ex wound, so could
take the extra voltage ok, but the higher operating speeds may give
weird results. The mowing deck motors are permanent magnet and could
well be damaged by the higher voltage, and again the higher speed might
make for strange cutting results.

Finally there are all the control circuits which might not take the
extra power.. and if you ever wanted to charge off a regular outlet,
you'd need a new charger.

Sorry to be such a bummer, but the practical, and admittedly
inefficient, solution would be to run the wind power through a 120 volt
sine wave AC invertor and then plug in your regular 36 volt ET charger.
Or if you are really lucky you can find some sort of appropriate dc/dc
-- Rich Rudman is working on a new charger that may take DC inputs, but
I think it is only for higher voltages of on-road EV's.


PS A wind system designed for 48 volts batteries probably puts out close
to 60 volts peak, so would need to reduce it a fair amount to charge a
36 volt pack.

_________
Jim Coate
1992 Chevy S-10
1970s Elec-Trak E20
http://www.eeevee.com