Re: Battery Question for components
And on the alternative side of the fence I do not set them up like that at all. In a small boat I far prefer two independent and isolated (but without the use of an isolator) systems with only the battery connection as an interface. Because we operate in a way that absolutly requires that we have backup the wireing methods mentioned above, while common and great for some boats, simply would not be safe for us. An Isolator gone defective can leave you with no power at all. They also drain a miniscule amount of power anytime they are connected, if you are using the boat or not. That doesn't work for me at all.<br /><br />I connect each battery (using identical combined dual-purpose Deep-Cycle/Starting type batterys) to the battery swtich input terminals. The engin's negative side cable is attached to one of the batterys and then a jumper is run to the negative cable on the second battery (you will need this jumper no matter what system you go to). The engine draws its power from the output lug on the battery switch, a cable from that lug also goes forward and supplies power to our circuit breaker panel (or fuse block). <br /><br />With this system you choose which battery you want to use for the outing, be it No. 1 or No. 2 doesn't matter. We alternate. So one battery is always held in reserve, fully charged, and able to operate any device on the boat as well as start the engine. There is no isolator or combiner to go bad and drain the system. Either battery can power anything on the boat. <br /><br />We also have an on-board charger that is wired into a very simple AC power system. The AC is comprised of a single GFI and breaker protected circuit to an outlet in the cabin and the circuit to the charger. We leave the boat on the charger virtually any time the boat isn't in motion. <br /><br />I do not have to charge while driving down the road because I leave the house with my batterys at 100%. We power two GPS's, two VHF radios, an AM/FM/CD player, a 600 watt fish finder, a Radar, and an Auto Pilot as well as all the usual lights, wash down pump (1), bilge pumps (3), live well pumps (2), fresh water pump, cell phone amplifier, and DC outlets for other portable devices. I do not have the luxury of testing my batterys to the 6 year mark, I replace them at 3 year intervals without concern to how much life they may or may not have left in them. Fishing 35~50 miles off shore in a small boat is like that, you can't take chances.<br /><br />I think the above system is just as good for smaller boats on fresh water but there is this one thing. If I had a boat that I used on a lake all the time and spent a lot of time just drifting or tied up with music playing or a live well running for hours on end I'd probably wire them to their own battery, completely outside of all of the boat's other electrical system, and then I'd just carry a set of jumper cables in case I needed to make a connection.<br /><br /><br />Thom
