Interesting group, I am (slowly!) beginning to gather some insight.
I have been reading the responses about the use of a Minnkota controller for a bigger motor, but would another way be to have a clutch like on a chainsaw, that engages with the revs? I know that there will be losses at lower rpm, as it gains speed, but might it allow the use of a straight switch?
Or just have a straight blade switch anyway?
Or a belt drive with flat belt (toothed belt the other side up?) and two transposed tapered pulleys.
Or a snowmobile style variable pulley system?
Also, relative to this, electricians have told me in the past that 'it is hard on the motor' when as a machinist I was maybe tapping holes, requiring throwing the machine tool into reverse with no time delay, like while the spindle is still rotating forwards. I have never understood what 'hard' means in this instance. The motor will create more heat, no doubt, and draw more current for an instant, but if this load type is only infrequent, such as when starting a boat moving, and maybe reversing it to slow down and maneuver some minutes later, then what's the harm. I know that some drilling machines used to have the max number of tapping cycles per minute stated right on a notice, so yes, it will create heat if repeated continuously, but why/when would you need to do that on a boat?
My point is, are there trade-offs that will allow the elimination of the controller? - after all this is not a road vehicle situation, so there is slippage built right into the marine application anyway. I see the controller as a real weak link, expensive, and not easily replaced in faraway places.
Provided that the HP rating of the electric motor is on the low side (which they tend to be) rather than the high side (as is the practice with ICE's) Then if snapped right on with a switch, it will surely just bog down and maybe hum (or is that only AC?) for a few seconds, and then start winding up to max revs, won't it?
And the (displacement hulled) boat will just sit there waiting, won't it?
And the amps will go real high, but then ease down as the load eases?
My own future plan is currently for multiple motors and on/off switches, so they can be switched on one at a time, with a few seconds between each.
I know that this would be unsuitable for a commercial turnkey setup but with care, controllers can be eliminated...... but does anyone know the power limitations in doing so, and has anyone actually tested this, (the need for a controller on a boat) rather than just been told it?
In short, I know that using one is the best way but is it the only way?
Same as 'Has anyone actually tested that 'deep cycle' batteries last longer' - bearing in mind that it is good sense to not drain any battery down too low. Maybe the whole deep cycle thing, at least in the cheaper end of the market, is all hype to sell pricey batteries? Is it not all about charge cycles per dollar, not just charge cycles? But maybe that's another topic.
John
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