RE: (ET) Re: new electrics

[Jeremy Gagliardi com]

Given the current conversation of "How do I build a better ET?" or "If ETs 
were
built to modern standards, what would it be?"  Well, if you're interested, 
I've
given this some thought lately, and here is what my criteria would be 
(read that
to mean, if I were the average consumer, this is what I would buy at 
Sears). 
Now, this is mighty lengthy, because it's an essay, not just an e-mail.  
Read
on, if you're interested, discuss if you like offline to Jeremy Gagliardi 
com or
online if ET related.

For the sake of discussion, let's put all of the mechanical and structural
elements aside, and talk only about the electric components, since those 
are the
only major difference from an ICE tractor.

Next, let's use the GE Elec-Trak E20 as the example tractor.

What are the major components of the ET?
 - Batteries
 - Charger
 - Drive motor
 - Front Lift
 - Controls (circuit boards and relays)
 - PTO receptacle
 - Accessory receptacle
 - Circuit breaker assembly and main disconnect switch
 - Lights and Horn
I am going to add one component that I think should be standard:
 - AC Inverter

Now, to build the tractor to modern standards, I put forth that these 
goals must
be met:
 (1) Use standard stock item parts, most of which can be found in any 
automative
or tractor store
 (2) The system should be all 12V DC so that the cheapest, most common
automative parts can be used.
 (3) The system should be simplified in 2 ways:
   (a) Simple to assemble and disassemble.
   (b) Simple to operate

How does one meet the above goals?
 - Use standard motors:
   - The drive motor would have to be beefy but operate on 12V.
   - The front lift I think could be powered by a 12V winch motor, perhaps 
--
something with a lot of power, but not a lot of speed.

 - If possible, use cheap batteries.

 - Use simple batteries:
   - The batteries should be sealed and require no maintenance.
   - Each battery should be easily pulled out and replaced.  That means the
power cables should have a simple attachment to the battery terminals -- 
perhaps
a clamp type attachment.  For batteries with standard posts, you could 
make an
assembly that keeps the +&- terminals held apart with a bar and keeps them 
in
the right order, + to +, - to -.  Make it foolproof so the batteries 
cannot be
installed backwards.

 - Use a simple charging system -- There are really 3 goals here:
   - The charger should simply connect to the batteries and allow you to 
plug it
in to AC.  It would simply charge when needed, and shutoff automatically 
when
not needed.  No timer and no need to monitor.  It should work on a 
standard 15A
AC outlet.
   - There should be an identical charger that can sit in your garage.  I 
have
this idea that it would attract more customers if the batteries could be
changeable, so that if one pack poops out, you can swap with a fully 
charged
pack, and get off and going again, just like refilling the gas tank, or 
more
simply like changing the battery of a modern power tool.  To achieve this 
goal,
there would be standard batteries on-board and a "light" pack that anyone 
who
could lift say 20 pounds could pull out and replace.  When the on-board 
pack
poops out, the tractor switches to using the spare pack (sort of akin to 
the
spare gas tank on a van or truck).  When the extra pack poops out, you 
pull it
out and plug it into the external charger, and unplug and install the 
charged
pack.  If the external charger is of the "quick" charge type, you could
potentially play swapsies all day long, and never have the stigma that 
once the
batteries are dead, your work is done, nor the "stranded tractor" syndrome
(simply carry over a spare pack and get the tractor back to the garage). 
Customers who would use the tractor heavily could buy even another charger 
&
pack combo and have more than one pack on charge for immediate use.  In 
order to
do this, the spare pack would have to be relatively lightweight.  It could
potentially be a single 12V battery that has enough juice to drive & mow 
for
about say 20-30 minutes.  The on-board pack could probably be 4-6 12V 
batteries
that could last for say 2 hours.  Most customers would probably never 
require
the spare pack.  The customer that would need to operate for longer than 2
hours, would probably buy the extra charger/battery combos.  Potentially, 
you
could make all batteries easily swappable, so every battery could be 
swapped for
extended use.
   - Offer a DC-to-DC charger for those who are off-grid.  If someone 
already
has a solar system, simply offer a DC charge controller as a replacement, 
or
possibly an add-on for the AC charger.  Perhaps, sell the tractor as truly 
green
by bundling the DC charge controller as a standard component.  Perhaps, 
bill the
tractor as dual charging, either from AC or from a DC system.

 - The controls should be all solid state and use changeable components.  
Fewer
moving parts means higher reliability.  If a relay burns out, simply 
unplug it
and replace it with a store bought replacement.  If the whole unit fails, 
simply
unplug the board from the tractor and plug in a new one from the 
manufacturer
(sort of like replacing a component in your computer -- the concept is 
open up
the access door, unplug the wiring assembly, swap the board, plug in the 
wires,
and stow it again).  Never should a user have to solder or use wire tools. 
 A
user would have to use no tool any more complicated than a screw driver.

 - The control assembly should have a simple interface.  The really simple
switches and double meter system used on the E20 is a great assembly.  
Although,
instead of an analog meter, I would replace it with digital (extreme 
temperature
tolerant, of course).

 - For the truly geeky, you should be able to pop out the existing meter, 
and
pop in a new one with more control, programmability, and features.  The
interface board when removed should allow the user to simply pop out a 
switch
and replace it with a new one without having to use a soldering iron.

 - Similar to the controls, every major component of the tractor should be
easily changeable.  Wires should be bundled together according to use and
attached to the tractor with pop-in/pop-out type holders.  Every wire 
bundle
would terminate in a quick-connect type plug.  Potentially, certain 
components
could be easily popped out and used separately from the tractor.  The 
Inverter,
for instance, could be unplugged and used in your car.  The charger could 
be
removed from the tractor and used to charge a spare battery.  Afterall, 
why do
you need a charger in the tractor when it's being used?  Potentially, even 
the
wire bundles would be easily changeable.  If a mouse chews threw a wire 
bundle,
simply unplug that bundle at both ends, pop it out from the body 
connectors, and
replace it with a manufacturer provided replacement part.  Light bulb 
burnt out?
 Pop out the bulb, go to your local auto store and buy a new one, and pop 
it in.

 - I think the accessory receptacle should be simply the AC plug on the
inverter.  There's no sense in getting into the business of selling 
propietary
attachments that can only plug into your tractor.  Simply go to Sears and 
buy an
AC powered string trimmer, and plug it into the AC plug on the tractor.  
See
next item...

 - All components would run on native 12V DC.  There would be no need for 
bulky,
expensive, and energy-steeling DC-to-DC converters.  Plus, with the system 
being
12V native, you could have a standard car power socket in the dashboard (or
wherever convenient) and use standard automotive accessories, like handheld
flood lamps, a radio with a car-adapter, a tire inflator, etc.

 - The PTO receptacle would be for the truly beefy attachments -- mower, 
snow
thrower, etc. -- all 12V.

 - The circuit breaker assembly should be centralized to include all 
components.
 It should be circuit breakers and not fuses.  But, if the circuit breaker 
ever
fails, simply unplug it and replace it with a new one.

 - I would say make the tractor grounded, like most cars, for 
compatibility.

 - For the front lift, possibly have it be a dual-purpose unit; one mode 
would
be the simple lift, and in the other mode, it would rotate a drum of wire 
to
operate as a winch.  This would increase the versatility of the tractor if 
a
standard item.

This has been my dream, and now I have voiced it.


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