Rob: In principle, either of the methods will work, depending on just how much current your stereo draws and how faithful you are about operating the switch. Niether of those are sure bets..... Most wakeboard boats I have seen that run tower speakers and subwoofers are capable of pulling 100 amps from the batteries. If you anchor in the cove and run the stereo loud enough to be blasting you while you are up on shore you will be pulling a lot out of the batteries. In a couple of hours you may have drained the batteries a fair amount, and then if you continue to run the stereo as you cruise around 30 minutes will not be nearly enough time to recharge. How big is your alternator? I have the stock 65 amp alternator on my boat. I run 4 tower speakers and a sub. The total power of the amps is 600 watts. Peak current to the amps is around 50 amps but I would guess the average is more like 25 when I am cruising. If I am running the stereo, bilge blower and ballast pumps the alternator does NOT keep up! And this is at wakeboard speeds, ~2800 RPM. In this condition, it is possible to drain the batteries even though the engine is running! When I shut the pumps and/or bilge blower off the alternator will keep up, but it doesn't have much margin. I would guess that I have less than 10 amps left over for charging the battery. At this rate, it would take 5 hours of cruising to replace what I might use in two hours of sitting. Tell us more about your setup and I can comment some more on it. Do you have amps? How big? How many? How are they connected to the battery? Any other large power draws? Tower lights? Ballast pumps? Heater? How big is your alternator? My standard answer to these types of questions is to get a "Battery Combiner" and connect it between the two batteries. Leave the battery switch on just one battery. If both batteries are the same type you might want to alternate which battery you use just so you can tell if one is starting to go bad. The battery switch will allow you to switch in the alternate battery to get you started if you run the primary down, and the battery combiner will always keep the alternate battery charged up and frees you from having to remember to do anything (it is all automatic)
|