Okay thank you all for quick responses!

I couldn’t find any labels on anything but I’m assuming everything is 12v since the batteries were wired in parallel and everything was working fine the few times I was out.

@pat k , I guess I need to look up how to tell if my motor is actually charging anything since I’ve only had the boat a couple of weeks. That would be really nice if it did!

@supercat this is kind of what I feared. The battery trolling battery went bad first and was from 3/18, the starter seems fine and its from 2016.
I’ll probably try to separate the circuits after my fishing trip this weekend for longevity of the trolling motor.

I’m also concerned about my new deep cycle batt. I took it home two days ago, put it on the charger till it said full charge and then charged the starter batt. Just now put the charger back on and it say the new batt is only half charged. Could that be one of those things were a new batt needs to cycle a few times to get a proper reading or something?