I really thuink the GPS and Fish finder are not the power hogs, my GPS takes less than 1 amp and Fish Finder on 1.0 amp even with the light on. The livewell will probably take about 3 amps or a bit more. At idle my motor will show about 13.2 volts, anything above idle it goes to about 13.8. I'm suspecting a weak battery, if it's a maintenance type battery, have you checked the fluid level? Like F/F said, get a charger on the battery for 24 hours with nothing connected, then wait 12 hours or so and check the voltage reading, if it's below 12.6 volts, it's on the way out, 12.3 is only 50% and anything below that, you're off to the battery store.