length of battery life fishing

[shorthairsrus]

my engine after it gives away its 130 some amps the engine - gives 50amps for the battery charging system. I have fished 8 hours trolling spinners on my electric - with stereo on, livewell on auto and electronics on (only 2) and the engine started. doesnt happen often but it has. One quick little move and the battery is back up to snuff. I replaced my original starting battery with a big one - from interstate that high cranking amps along with life.