Re: will my idea work?
Could your idea work??? Perhaps, but it is a lot more hassle then you need it to be. I would look at something like the Sure Power 1314. This is a switch that monitors the main battery voltage and will connect the two batteries as long as the main is above 13.2 volts (also read as charging), once it drops below this it will disconnect the two batteries which keeps the main charged and allows the secondary to discharge. While this will protect the main, it does not solve the fact that it is still a losing proposition when you look at how many amps the outboard puts out vs how many amps are being drawn from the battery. At 9 amps vs a 45 amp draw all it would do is delay the inevitable slightly. It would however autmaticlly charge the battery when you are cruising on the main engine between spots.
Could your idea work??? Perhaps, but it is a lot more hassle then you need it to be. I would look at something like the Sure Power 1314. This is a switch that monitors the main battery voltage and will connect the two batteries as long as the main is above 13.2 volts (also read as charging), once it drops below this it will disconnect the two batteries which keeps the main charged and allows the secondary to discharge. While this will protect the main, it does not solve the fact that it is still a losing proposition when you look at how many amps the outboard puts out vs how many amps are being drawn from the battery. At 9 amps vs a 45 amp draw all it would do is delay the inevitable slightly. It would however autmaticlly charge the battery when you are cruising on the main engine between spots.