On 10/10/10 21:34, gentlemancaller2009 wrote:
> The Etek-type motors generate more torque and higher rpms at 36 volts than the MK lower end does. I can get the performance I want out of an Etek motor fed 36 volts: that's why I want to use it.
>
> As I see it, that combination won't burn out the controller, it will only make the engine run slower than maximum 48-volt speed, and that's fine with me.
>
> The motor will only get the voltage and amps the controller will allow. If that's not enough to turn the motor at top speed, fine. But I don't see how that can burn out the controller, since it's operating in volt /amp ranges it's designed for, and there's no way the motor can draw more power than the controller will provide from a 36 volt battery pack.
>
The controller could end up operating in 'current limit' all the time.
Depending on how it's electronics are designed, over time, running at
it's limits, it may overheat.
The etek motor will try to draw what ever amps it requires to obtain
the RPM that is dictated by the applied voltage, so depending on the
prop, it may very well end up 'bouncing off' the current limiter in the
controller all the time.
One advantage of a 'generic' motor controller is you can generally
program them to go into current limit below the maximum rating of the
controller. (This is what I did), so at no time should my controller be
operating at it's design limits, even if the motor stalls. This should
(all limbs crossed) mean I never burn the controller out and as I have
the limit set below the 1hr rating of my motor, I should never burn it
out either.
The Minn Kota controller is probably designed to match their motors
characteristics, and may not even have effective current limiting as
they know what the maximum stall current from their motor is and
designed around that. It's going to come down to if Minn Kota designed
their controller 'from scratch' or just bought in some one else's
controller and 'configured' it for their application.
The fact that Minn Kota saying changing the prop could burn out the
motor tends to lead me to believe their controller doesn't current
limit, as it certainly appears it doesn't current limit to protect the
motor, so it may not current limit to protect itself either.
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