Electrical Question

[wonko]

Pretty much re-doing the electrical system on the boat. Two engines, two batteries, two 1-2-both switches. Two questions.<br /><br />1. How do I ground the batteries? Both to one engine to share the same ground? One to each engine (what about electrolysis)?<br /><br />2. How do I hook the 1-2-both switches up properly? They weren't hooked up before so I have no clue. They are just the standard red ones you see in all the books.<br /><br />Thanks in advance.

 

[cclemon]

Re: Electrical Question

Wonko, Let me start by saying I don't know much about boats, but maybe we can inspire someone to help us. From a purely electrical stand point. It would make since to connect the batteries in parallel "Positive to positive and negative to negative. Both engines should be to the battery negative. Both engines connect to the batery positive. This configuration would allow maximum power for starting. BUT BUT BUT. I don't think this is going to work well for the charging systems. Maybe that is what the 2-1 switch is for. Like I said I am electical, not boat savy. I do hope we get some help on this one. I am curious also.

 

[Trent]

Re: Electrical Question

 

[Kenny Bush]

Re: Electrical Question

Oilslick is on the right track. The battery switches should be used to isolate/parallel the batteries. Each motor should be hooked to it's own battery and the switches help hook up in parallel. I personally would use 3 batteries. 1 on each motor (pos. 1), and a 3rd(pos. 2) auxillary. Each switch when turned to "2" would run off auxillary, and when turned to both would run off motor battery and aux battery. If both switches are on both, you will be paralleling 3 batteries. As for charging, if you run both switches on "1", they will be isolated and the motors will charge accordingly. If you put one switch on both, that motor will charge its own battery and the auxillary(Both batteries will only be as strong as the weakest battery).

 

[petryshyn]

Re: Electrical Question

Wonko<br />Few more facts needed.....<br /><br />>what is the output of each O/B charging system?<br />>what are you running for accessories off of these batteries?

 

[wonko]

Re: Electrical Question

Schematic, to answer the question, both motors have an alternator and both push 12v (I assume, haven't tested with a multimeter, but that's what the guages are for). <br /><br />As far as accessories, I don't have too many and I currently have all of them wired to one battery. I do have two 12v breaker boxes so I could seperate the accessories very easily if you think it is a good idea. <br /><br />Accesories:<br />2 bilge pumps<br />4-5 little interior lights<br />running lights<br />horn<br />electric anchor<br />basic engine stuff<br />1 Furono Depth Finder/Sounder/Plotter/LORAN<br />1 small Hummingbird depth finder<br /><br />Any idea about how to do the grounding? Should they be common on one engine? That's what it looks like from the diagram from above but....

 

[petryshyn]

Re: Electrical Question

If you are not draining a battery dead with the accessories on a regular basis, I'd go with the bottom diagram on Trent's post. I'd connect the accessory feed to the "com" terminal of either of the two switches. This will allow you to alternate the acc. load from batt1 to batt2, maximizing battery life. (eq. one time out, use switch positions 1+2, next time out use 2+1) This will help prevent either battery from continuely getting discharged by the acc load.<br />