ok, looks like i have more homework and some explaining to do...
1st off thank you very much for the feedback, and thank you for being active forum members (a dif forum i tried is apparently inactive)
Yes I was looking at Pulse Width Modulation, as it increases efficiency and maintains torque (from my understanding) I would be perfectly happy to use voltage regulation in place if that will be easier and will not cost me greatly in efficiency...and would prefect switching i think over linear.
Yes I am sure it was 50A I was looking at, I used an inline Watt meter rated for 75A to check it It moved between 49-50A at 14.5VDC.... 725watts... granted that was tested in a 55 gallon drum and the load would likely drop once the boat begins moving.... but for positioning and as a safety net I feel it wise to call it 50A so that whatever I wind up with can handle the draw for sure.
Yes I am trying to use a trolling motor as a trolling motor not as anything else. What I am trying to do is get a working electronic speed control unit that is reversible. The idea is that if i can get one unit to work then i can get two to work. I have a pontoon boat 20ft long that I am intending to put one trolling motor at the rear of each pontoon of, then I would like control the motors independently via a joystick (pulled from an old rc plane radio) through a mixer (got that unit standing by) so that full up on the joystick is full FWD on both motors....full down is full reverse on the motors, and left or right is full REV on one and full FWD on the other... with any combination of that capable for smooth tank like steering.
Here are a couple other options that I am considering...
Build a Versatile Miniature High-Rate ESC with BEC and Brake this is a description of the ESC,
http://www.stefanv.com/quiet/escboth/figure1.gif this is a link to the schematic.
The issue with this one is that it does not have reverse otherwise perfect. i think... would it be possible to mirror the drive portion of the circuit to accomplish reverse....or use relays to flip the polarity as it goes to the motor to accomplish reverse?...
or am I much better off purchasing **broken link removed** this and just sucking it up with a $300.00 bill at the end... going to interesting explaining it to the wife.
I really would like to build the ESC, if for no other reason than pride... I am also trying to return to learning electronics... but as I said highschool was a long time ago...wish i would have been a better student. I use ESCs both brushed and brushless on almost a daily basis in the RC hobby, and would sure like to be able to upgrade and repair them as needed.
thank you all again for your time and patience.
Sean