I've been using a Headline (a.k.a. Cyclone) brushless motor controller
and Headline motor with a cheap, generic Hall thumb throttle (due to
limited handlebar space) and have been unhappy with the throttle
response that is close to that of an on/off switch. I don't blame the
throttle for this as this same throttle gives nice, gradual response when
used with a controller made by a different manufacturer.
So, I set about to seeing what I could do to improve the throttle
response to be more gradual, so that it was fully "on" when adjusted to
be so, fully "off" with no motor creep when at rest, and gave nice,
gradual response in between.
The Headline controller shows a curious schematic on its box:http://tinyurl.com/lwl5eu
suggesting that the controller is designed to use a 5 kOhm
potentiometer throttle and not a Hall throttle. This is in spite of
the fact that Cyclone motor kits come with a Hall throttle that seems
to work well enough (again after some tweaking that as I recall
involves placing about 150 Ohms in series with the GND lead).
I performed two experiments and arrived at conclusions after much trial
1) I wired up a 5 kOhm linear potentiometer (pot.) and then proceeded
to add resistance to each of its various leads.
The 5 kOhm pot. by itself was as poor as that of the Hall throttle. No
response for the first 2/5 range, then full response by 3/5 range.
But, when I added 20 kOhms in series with the GND lead I was able to
use the first 2/5 of the range, making the pot. effective from nearly 0
to 3/5 range or perhaps a bit more. Unfortunately, the upper 2/5 of
the 5 kOhm pot. throttle range was still not usable, equivalent to
2) After placing resistors of varying size on various Hall throttle
leads, I settled on the following:
I inserted 1.134 kOhms in series with the Adjustment lead and inserted
420 Ohms in series with the GND lead.
Adding resistance to the Adjustment lead extended the upper range of
the throttle, and adding resistance to the GND lead extended the lower
range. I was now getting graduated throttle response between roughly
1/3 and 4/5 of the throw. I tried capturing more at the lower end, but
any increase in resistance on the GND lead caused motor creep when
throttle was at rest. It appears that the first 1/3 of the throttle
throw is dead space.
In fact, I started with 452 Ohms on the GND lead and initially observed
no motor creep when the throttle was at rest. I went riding. After
climbing a long hill, the motor and controller were both warm, and the
motor was creeping when the throttle was at rest. I figured that as
the temperature of the controller warmed, the resistance of the circuit
increased just enough to cause it to pass the "creep threshold".
With the modified throttles, I do experience one minor side-effect:
When the controller is powered up or powered down, the motor will
"jerk" forward briefly, but not dangerously so.
Aside from providing this information to others using these controllers
who may be experiencing poor throttle response, would any of the
experts in this group care to speculate on why these controllers
respond poorly to an unmodified throttle, Hall or 5 kOhm?