I’ve added a Panoptix to my Garmin 9svuhd fish finder. My current 12 volt battery runs both the fish finder and my 45 lb trolling motor. Will this power source be adequate for the Panoptix, or should I have a dedicated 12 volt battery for the fish finders?

Depends on the battery but you should have a separate battery anyway. It’s far more likely to get interference on the fish finder if you run it on the same battery as your trolling motor.

 

a 9” screen and live scope draws about 3 amps I think on high (bright screen, running everything).  A typical 45 lb trolling motor on medium high (not full high) is going to draw 25 amps. That’s 28 total. A group 31 big deep cycle is a 100 ah battery but around the 30% mark you’ll drop below the threshold for running some electronics. So 70 ah / 28 amps is about 2.5 hours of running. If you’re going slow down the bank then the motor will go a lot longer of course. If you’re motor fast a lot less. 

If you have a bunch of 18v batteries for your powertools, buy an adapter and run the Livescope from that. Saves you the charger and battery weight.