battery draining

[mark barton]

I left my boat for 2 weeks, went to turn it over and battery dead. Charged battery over night, went fishing next morning started fine. Trolled around for couple hours, started good again. trolled for about another hour and battery dead. Went through the same situation following weekend. Had batter checked and battery is good. Any ideas???? It is a 2004 750 nitro with 90 hp mercury carb 2 stroke. Starting battery and one trolling motor battery.

 

[G8rmac]

Start with the basics-check all connections to make sure they are clean and tight. I had a similar problem, cleaned the battery terminals and wire connectors with a wire brush until shiny and tightened the nuts with a wrench (no finger-tight wing nuts!) It is surprising how little corrosion it takes to block the charge from getting through.

 

[Berry Lindley]

So, is your starting battery the one going dead on you? I could not tell for sure from the description of the problem which one was dying. I am assuming so. If this is so, and the connections are good, then my first step would be to confirm that your charging system on your engine is working. You should be getting something like 14-14.5 volts when the engine is running. You also need to confirm that you have only the engine and fish finder (and pumps) on the starting battery, and the trolling motor on the trolling motor battery. Also, you need to confirm that you have a marine cranking or dual purpose battery for the engine, and deep cycle or dual purpose for the trolling motor.

 

[mark barton]

Yes it is my starting battery. It is a marine cranking battery. Only have pumps, depth finder on starting battery. Connections are good. Volts are running about 12-13.5 volts when running.

 

[Berry Lindley]

Sounds like something awry in the charging system, I'm guessing stator....When you get your RPM's up it should be charging the battery. Good luck.