I cannot find a definitive answer, just that deep cycle batteries are not built for crank batteries. Of course.

I have a 15' Boston Whaler, 60 HP Merc, 55# Minn Kota on the bow. Currently I have two batteries, even though the Whaler stock supplies only one. and they run the running lights from that one too. One battery is strictly for cranking the Merc. Unlike my previous experiences with Mercs, this 60 is bombproof. I can let it sit for weeks and it will fire up in maybe 1.5 seconds, tops.

The other battery is for everything else, including the trolling motor and the electronics. I can go a full day on the Delta with nearly continuous trolling motor use and be down to 60% at the end of the day.

Both batteries are AMG, 100 AH each.

The weight under the side console is enough that combined with a starboard bow trolling motor mount the boat can list to starboard a bit on a run when I am solo. My thought was to replace the two batteries with one, cutting the weight by more than the entire weight of the trolling motor. I would get 100 amp hours in this case which I guess would approximate the 200 AHs I have now with two batteries.

Any experience based opinions? Thanks so much!

JOhn