I agree about charging a lead acid deep cycle up as soon as you get home or. In fact I would recommend that it be put on a trickle type charger that automatically maintains it at full charge. I have one of the newer Minn-Kota Battery chargers that charges fast at first then slows down as the battery comes up to full charge. I think it maintains a trickle charge too but I would have to go read the manual again.

One thing you may want to do is keep the trolling motor connections seperated from the depth finders connections. Not sure but some times you can get an interference in the depth sounder.

I basically only have my starter battery hooked up to the motor. I do have a live well pump and the bilge pump hooked up to that battery but they are seldom used. I think that when I run the motor it's alternator will recharge my starter battery keep it fully charged. I use an Optima Blue Top Cranking battery for the starter battery. I use a Optima Blue Top Deep Cycle Battery for the trolling motor. I am not really sure if this is the best way to do things but it's how I have been doing it for years now and it seems to work for me.
Regards,

Moose1am