I have 3 Lowrance Hds units, power poles, NMEA network, Point 1 heading sensor, Bluetooth electronic compass for my trolling motor and the drain from my power switch. My battery has run down 2 times this fall. Interstate replaced the dual purpose Optima battery that I had. That did not fix it.
I went back and they said no go on another replacement so I bought the biggest badest AGM that they have. Even it gets pulled down to where the chart plotters flash every time I start the motor after fishing for a while.
Since I have a perfectly good blue top Optima, I am going to pull everything off the cranking battery except the power poles and the outboard and put them on the Optima. I have found room for the 5th battery.