If you use the whole 24V from the trolling battery and run it thru a step down DC-DC device ..... It's POSSIBLE you would get enough isolation from the trolling motor battery to prevent interference .... but I have not tried it.

I thought about trying that, but in the end decided I wanted the electronics totally isolated from everything else and got a dedicated LiFeP04 battery just for electronics. Mine has a Bluetooth BMS and status and parameters can be adjusted from a phone.

If you have a while before you need to decide, order one direct via Alibaba and save some money ....all the LiFe batteries come from China anyway .... or make your own using individual cells if you are handy with this stuff. If you decide to try ordering direct, shoot me a PM and I will give you a forum where you can do your homework to find a reputable seller.