FIrst things first: find out what's going on.  You need a proper ammeter so 
you can measure the actual motor current.  If you have one measuring battery 
current, why not move the shunt so it's measuring motor current?

Alternatively, you could buy another ammeter.  The ones sold by EV parts 
dealers for in-car instrumentation are usually a shunt (typically 500 amps 
at 50mv) and a millivoltmeter.  I see a cheap one on Ebay right now at less 
than $23 shipped. I wouldn't want to vouch for its durability or accuracy.

You can get the shunt only, substitute a DMM for the meter, and do the math 
yourself.  I recommend having a passenger read the meter for you.  

My fist inclination is to say that it sounds like you have a controller 
problem.  I've seen logic failures in 1980s vintage PMC controllers that 
caused them to act like the battery was flat and limit drive current to 50 
amps.  I don't know whether a Kelly would fail in a  similar way, though.  

In any case, FWIW, Kellys aren't exactly considered the upper crust of 
controllers.  :-(

What you need to test the controller safely (in addition to the ammeter) is 
a dummy load of some kind.  Some EV hobbyists build them, usually for 
battery testing, with electric water heater elements in a barrel of water.  
That could be a lot of elements, though, since a 4000 watt 240v element will 
only draw 1250 Watts (~8.7a) at 144v.

Years ago I used a fan and heating strips from a derelict heat pump to make 
a dummy load.  The nice thing about using open nichrome wire elements 
instead of the sealed elements from water heaters was that I was able to 
center-tap the coils and parallel the halves to make the elements use more 
current at lower voltage.  It was good for around 100a at 144v.

Maybe others here will have more dummy load suggestions.

As for the motor, I don't think that unseated brushes would inhibit motor 
current that drastically.  I could be wrong.  

Try running the motor on 12v (no more) with the trans in neutral, or drive 
wheel end of frame on jack stands.  Does it run reasonably well with minimal 
brush arcing?

Your brush problem report is puzzling.

I don't understand "the left side on both brushes was mostly shot."  I've 
never thought of brushes having a left or right side.  

If by "shot" you mean brush wear, that much is not normal.  IIRC, GE once 
estimated that their DC motor brushes were good for at least 250,000 miles 
of EV use.

According to the evalbum entry, you have a Honda with reverse motor 
rotation.  Are you sure the brush timing is set correctly for that?  Maybe 
your brushes were eroded by excessive arcing.

When you say "On one brush, the copper braids were completely gone.  On the 
second brush, the copper braids were nearly gone," do you mean that the 
brush pigtails were burnt?  That seems like a different issue to me.  

I'd lay pigtail burnout to gross overload at low speeds or stall.  I did 
that to the brushes in my Comuta-car motor when starting on hills.  But you 
just don't see that kind of overload with a controller limiting the current, 
and ADC 9" motors are a lot more durable than my C-car's feeble little 6hp 
GE.  So this seems odd too.  But maybe I'm misinterpreting what you wrote.

David Roden - Akron, Ohio, USA
EVDL Administrator

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