[sikeston34m]

Some good questions and good observations.

First off, I would like to say that most things that run on 12 volt lead acid power have an operating voltage range of 10 volts to 15 volts.

This 10 to 15 voltage range doesn't line up with the cell voltage of Lithium Ion very well.

I considered using both 3S Or 4S configuration.

3S would not perform as good since fully charged is only 12.6 volts. At 10 volts, when the motor stops working, due to low voltage protection for lead acid, there will still be capacity left in a 3S pack. Only discharging to 3.33 volts per cell isn't using (or making available) the full capacity of the pack. I also have a feeling the motor just wouldn't perform well.

4S sounds peppy, but the pack could only be charged to 15.0 volts to stay inside the operating range of the trolling motor. How much capacity would be lost if we only charge to 3.75 volts per cell? Alot I think.

Yes Linc, these are 2C cells. I'm predicting about a 25 amp draw on the 6S pack going into the converter array at full speed. The pack will be capable of alot more than that, but overkill is good and less stressfull on each cell. This will make things live alot longer, especially since it isn't going to be ran at full speed all the time.

Yes, a constant 13.8 volts flat throughout the discharge. The converter array has sensor leads at the load to constantly maintain the 13.8 volts, even under the load. This points towards better than lead acid performance. It's one of the reasons why I like this idea.