I'm not an expert by any means on livescope, only had mine 4 months or so. I can say they do use up alot of juice if your using it for more than 3 or 4 hours each outing. I think most prefer a designated battery for the unit and black box. If you go to one dual purpose battery for starting, helix unit and livescope system I would test the life span of said battery in short intervals. Or atleast have a jumper to crank motor off one of the TM batteries if it came down to it.

I would assume a good group 31 would serve you well, but can't attest to it with full confidence. I run a 31 battery with big motor, helix 9 on console, helix 10 on bow and the Garmin and box separately off two dual purpose 24 interstates in parallel. Two designated 31s for trolling motor. I see alot of folks posting pictures with the livescope units running low voltage, in the low 12 or upper 11 volt range. I have 5 batteries total and probably overkill no doubt, but I have piece of mind I'm never going to be caught without enough juice to turn my big motor over hopefully.

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