I have had several skiffs w/ a trolling motor and one battery--- and I have never had a problem. This includes a live well and electronics.
I did make sure that the motor had a charging unit installed.
However , I was not a shorline beater that used the TM till the batt. dies.
The batt. never got close to failing.
My current setup is a 1 batt. suv17.
my 2 cents