RE: (ET) E12S and a Curtis controller??

[Dave & Debbie Barden <daveb seanet com>]

my new chargetek charger, the one that charges 3 12v batts, came in the 
mail 
yesterday.  My friend Craig has his doubts that it will work the way I 
think it 
will.  That is NOT having to split the pack into 3 pairs of 6volt batts.  
I 
didn't ask but it sure sounds to me as though this charger does NOT have a 
common negative rather 3 separate negatives.  Craig's point was that if I 
don't 
split the pack and the charger uses a common ground I have  an immediate 
dead 
short.  Anybody out there know for sure.  

this discussion about motors and controllers has indeed been informative.

dave
Seattle

> I agree good discussion! IF the motors will take the extra voltage and
> it sounds like they will then taking out the charger and replacing it
> with a 6 volt battery sounds like the way to go. If you do not want nor
> need the extra voltage just leave it the way it is. Using a modern
> controller will make the number of connections less and we can use
> larger wire and better connectors than the factory did. The bottom line
> is we may not need the extra battery to make up for all the voltage drop
> in the old system. Has anyone put a voltmeter on the motor connectors
> and driven up a hill to see how much it drops under load? My guess is a
> lot. Even on cold days the wire bundles gat warm and the contactor
> cabinet is warm, heat is loss. The voltage at the motor is what makes it
> go not the voltage at the battery terminals.
> 
> It will be good to have a controller that we can program to set the
> acceleration and deceleration! This is going to be fun! 
> 
> The 36 volt battery charger that charges three 12 volts battery systems
> looks interesting. My E20 wants one!
> 
> Steve, yes we need cruise control! 
> 
>  Dwight   
> 
> Dwight L. Hazen, Indiana University, UITS 
> 
> Bloomington, In. 47408-7378
> 
> 812-855-5367 IP phone 317-278-4014    
> 
> hazen indiana edu http://php.ucs.indiana.edu/~hazen/
> 
> Ham Radio wb9tlh arrl net http://wb9tlh.ampr.us
> 
> 
> -----Original Message-----
> From: Andrew Poush [mailto:agp vt edu] 
> Sent: Saturday, June 28, 2003 10:33 PM
> To: elec-trak cosmos phy tufts edu
> Subject: Re: (ET) E12S and a curtis controller??
> 
> Wow.  I am really pleased with the discussion that spun off my email.
> 
> David Roden is pretty accurate in what he says about Mark Hanson's 
> modifications.  I should know because I own one of the two E-15s Mark 
> modified.  And I did my graduate studies in DC-DC power conversion and 
> motor control.  Mark did use two identical controllers, one for the 
> drive and one for the PTO.  The battery pack is 48V and the accessories 
> are tapped off the pack.  I can put the tractor in any gear, vary the 
> speed command so that any voltage from 0 to 48V is applied, and it is 
> efficient and smooth.  I never need to change gears while I mow.  I can 
> throttle down and switch to reverse in a blink, even if the tractor is 
> not quite at rest.  I never use the foot brake while mowing since the 
> reverse is so handy.  But my top speed is 4 mph whereas before the 
> modifications it would have been 10 mph.  I don't really NEED the speed 
> for mowing and snow-plowing.  I just want it for the fun of giving my 
> daughter faster rides.
> 
> David did say that he would trust that since Mark put a second 
> controller on the PTO that it must indicate that running the mower deck 
> at 48V is too risky to attempt.  In fact, Mark told me just the 
> opposite.  The mower motors can be run at higher voltage with little or 
> no risk.  I generally run them at 36V but crank them up when the grass 
> gets very thick.  I have run them that way for over a year and never 
> tripped the thermal overload or gotten the motors hot enough that I 
> couldn't hold my hand on any one of them indefinitely.  This E-15 is a 
> great ride and I only look forward to it getting better if this kit 
> Steve's company is developing can be made affordable.
> 
> One more feature I would like to see on a controller for the ET is 
> cruise control.  The ability to set a cruise speed and then reduce 
> speed (or even reverse direction) for maneuvering around obstacles and 
> then resume the preset speed would be very useful to me.  Currently, I 
> can set a speed but cannot resume it after changing speed.  The speed 
> command input to the controller is a slider potentiometer next to the 
> forward/reverse switch (rather than a foot pedal).  I am not sure that 
> a foot pedal is compatible with implementing a cruise control cost 
> effectively.  What do you think, Steve?  Is cruise control a 
> possibility?
> 
> Andy
> 
> PS - I will never go back to a 36V battery pack.
> 
> 
> 
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