From: "Christopher Meier" <mr23 mn rr com>
To: <pctrice purdue edu>, "David Roden \(Akron OH USA\)" <roden ald net>,
"'elec-trak cosmos5 phy tufts edu'" <elec-trak cosmos phy tufts edu>
CC: "Phil C Trice" <pctrice purdue edu>
Subject: Re: (ET) DC-DC Converters - Lot of 6
Date: Thu, 28 Mar 2002 02:09:56 -0600
I think Bill Dube gave some compatible units to Rod Wilde to sell for him.
I've been meaning to call them up and ask them. I'll try to do so Thursday
and report back if he has any left.
-Chris
----- Original Message -----
From: "Phil Trice" <pctrice purdue edu>
To: "David Roden (Akron OH USA)" <roden ald net>;
"'elec-trak cosmos5 phy tufts edu'" <elec-trak cosmos phy tufts edu>
Cc: "Phil C Trice" <pctrice purdue edu>
Sent: Wednesday, March 27, 2002 8:25 AM
Subject: RE: (ET) DC-DC Converters - Lot of 6
> David,
> (At the risk of lowering the signal/noise ratio :-), You raise some very
> good points. I looked at the spec sheets for these yesterday, and came
to
> the same conclusions.
> The point remains, though; are there any DC-DC convertors out there that
are
> usable (ie, reasonable current capacity, size, etc) and affordable?
Barring
> that, are there known, stable designs that could be turned into usable
> products?
>
> -Phil Trice
> 1976 Sears Electric tractor
>
>
>
> -----Original Message-----
> From: owner-elec-trak cosmos phy tufts edu
> [mailto:owner-elec-trak cosmos phy tufts edu]On Behalf Of David Roden
> (Akron OH USA)
> Sent: Tuesday, March 26, 2002 2:32 PM
> To: 'elec-trak cosmos5 phy tufts edu'
> Subject: Re: (ET) DC-DC Converters - Lot of 6
>
>
> On 26 Mar 2002 at 12:57, Chapin, Tim wrote:
>
> > 6 dc-dc converters on ebay..
>
> Careful! These are for 24 and 48 volt nominal input, so unless you've
> upgraded your ET to 48 volts, they wouldn't help much (you'd still have
to
> tap the pack). The specs say "18 to 36 volts" for the 24 volt units,
but
> that's intended to leave "headroom" for higher voltage during charging,
not
> for routine operation.
>
> If you tried to use the 48 volt units instead, you'd have problems. They
> probably won't put out full current, and are more likely to overheat,
when
> run below nominal voltage. Also, when you loaded the tractor and the
pack
> voltage sagged, they'd probably drop out.
>
> Finally, each is capable of delivering only 20 watts. That's about 2
amps
> at 12 volts -- barely enough to run the headlights, if even that. You
might
> be able to parallel all six and get 8-10 amps (DC:DC converters don't
share
> loads perfectly, so you probably wouldn't get 12 amps), but you'd still
have
> the input voltage problem.
>
> These DC:DCs probably have some uses, but I wouldn't buy them for an
ET's
> lights and/or lift.
>
>
> David Roden - Akron, Ohio, USA
> 1991 Solectria Force 144vac
> 1991 Ford Escort Green/EV 128vdc
> 1970 GE Elec-trak E15 36vdc
> 1974 Avco New Idea 36vdc
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