Re: Installing 4 batteries need wiring diagram
To start with, you can think or your 4 batteries as 2 pair of batteries. Each pair is really a single battery in 2 parts; so think of your 4 batteries as 2 big batteries. Add the pair at the helm as a separate battery and now you have 3 big batteries.<br /><br />Each pair will be wired in parallel; [+] to [+] and [-] to [-]. When that is done you have just increased the capacity (amp hours / current) available of the existing battery. Thats why I said you could think of each pair as a single battery.<br /><br />Whenever you get creative with wiring batteries in series or parallel, you should only be using batteries of the same make/model/age. If you already have two batteries like that (maybe one for each motor?) you can hook those up in parallel for your starting bank, otherwise you should start with new batteries all around.<br /><br />Are you thinking of flooded cell batteries (most common), or AGM batteries? There are flooded cells designed for specific applications, i.e. starting batteries for starting and deep cycle batteries for running everything else. We call those the starting bank and the house bank
bank as in bank of batteries. There is nothing wrong with increasing the size of the house bank to accommodate that laptop. When you return from boating, youre going to be shore charging more than just the second house bank at the helm anyways. In the overall scheme of boat electrical, it might be easier to go with a single house bank consisting of 3 or 4 batteries, then run really simple wiring to the helm for a 12v receptacle. This way when you return to shore you can charge the whole house bank at once. Normally you wont see two separate house banks until you get into yacht-sized boats.<br /><br />Someone here (Thom) has come up with a novel way to use two identical banks of dual-purpose batteries (not starting, not deep cycle) and switching which bank is used for what application each time he goes out. The idea doesnt appeal to me but he has been doing it for a while without any problems and he always has the juice to start his motors for the return trip home. Maybe Thom can weigh in with his application.<br /><br />Something else to think about, when you start adding more than a couple group 24 or 27 batteries, it can be less expensive and more convenient to go with a single big battery like a 4D or 8D. That also omits the need for jumper cables between batteries wired in parallel, if you have flooded cells the maintenance is easier, etc. You do need to take into account space and weight distribution. If you really want to cram a lot of power into a small footprint, you can get a couple NorthStar NSB210FTs, AGM batteries. They can go down to 80% discharge. Thats a 22-inch by 10-inch footprint that yields 330 usable amp hours of current. Or you can get 200 usable amp hours out of a pair of NSB130FTs in the same footprint. If you get the NorthStar AGMs (priced similar to West Marines gel batteries) you can get them planning on 50% discharge and then you will have about another 30% headroom, if ever needed.<br /><br />As far as battery switches go, in general I recommend Guest HD line. There is no other battery switch as heavy duty as those. Most marine battery switches are seriously undersized for situations where a motor is hard to start and you need to do some cranking. Next best battery switch is made by Blue Sea System, but they arent as heavy duty as the Guest HD for sustaining high amps. For about the same price as a Guest HD switch you can get a battery bank crossover solenoid and put a switch at the helm. If your starting bank depletes you just press the button and turn the key. The engine(s) will be starting off both banks bridged/combined.<br /><br />Btw, I hate gel batteries and I hate those spiral-wound gelled AGM batteries (Optima and Orbit). So if you have or are getting any of those batteries, dont tell me.
