Battery Wiring very CONFUSING

[SeisNudos]

I recently purchased a Ben First 38.5 - 1983 - The first owner purchased it and placed it with The Moorings for about five years, sailed for a few and then abandoned the boat. I pick it up in Fort Myers and sailed to Miami. This is a machine! It's fast and easy to maneuver.

I am trying to understand the big Red Electrical Switches on the walkway behind the engine compartment labeled: Engine - Utilities - Macerator.

The battery compartment has two big fat cables (Black and Red) and one Black thinner one from the Alternator. With these cables you can only use one battery (or two in parallel), where there isn’t a separate House and Start Battery setup, which is what I would like to have. I don’t want to have to untie all the cable harnesses to find out what goes to what.

Please look at the attached diagrams (Actual, IDEA and Final) and please send me your comments, suggestions and send me actual ELECTRICAL diagrams if you have them. With my final IDEA I can always use the Big Red Switches to isolate circuits. The user guide's is worthless!

I used to work on real big big computers (IBM) so electricity is my friend, as long as I have…

Thank for responding!
Seisnudos@comcast.net

 

[JohnShannon]

That is confusing, why are you going to touch it? If you start messing with it, just follow Maine Sail's advice (elsewhere on site) and go for house and starter with echo charger (hope I got that right).

There is a possibility the wiring isn't quite what you think it is, and even though you aren't afraid of electricity I would be leery of innovating in this area when it seems like sound well thought out advice is easily accessible.

At a min, you want fuses on the batts.

My 375 had 3 switches two red and a black, the black had the feature that if thrown while the motor was running the electrical system would blow up.

Now my 375 has a blue sea systems switch with alternator field disconnect so in principle just before the main power breaks the field winding is opened and alternator output turns off. Also has a surge suppressor at the alternator terminals.

 

[Stu Jackson]

Beneteau wiring

Attached photo is the "basic" Beneteau wiring diagram with the three (2 red one black) switches.

I've looked at your diagrams, very briefly, and find that the "Unknown Connections" are kinda a giveaway about how to approach this issue. If it was my boat, I'd trace the wiring, first and foremost, to understand how it was supposed to work, and then how I want it to work.

Good luck.

 

[weinie]

Re: Beneteau wiring

What Stu said.

 

[SeisNudos]

Re: Beneteau wiring

I only have two fat wires (Red/BLk) in the battery compartment and a thin one for the Alternator. If I had TWO reds your diagram is OK.

 

[Ron20324]

Okay, first off, are all three swtches red-handled? It sounds like the macerator switch was changed from a negative switch (that used to have a black handle) to a pos switch/red. I'd wonder if there is a fuse on the macerator? The macerator should be wired off of the DC breaker panel, which Beneteau planned for. ((When I added a third battery to my Benny 323, I changed the black for a red, but that's another story.)) I'm sure someone got their mitts into the wiring and did the cheapest/easiest/shortest wire run thing. (Moorings told us to NOT fiddle with the switches when we chartered.) Stu's diagram is what my boat started with, too. Also, are your 2 batteries strapped together, +to+, - to -? I can help you further, but this info will help us. There is a better way than what the factory did. You can email me if you want to.

 

[SeisNudos]

Yes the switches are all red. Since there are only two fat wires in the battery compartment there must have been one or two batteries in parallel. Do you think my "Final" diagram is OK?. Thanks for your reply!

 

[Stu Jackson]

Yes the switches are all red. Since there are only two fat wires in the battery compartment there must have been one or two batteries in parallel. Do you think my "Final" diagram is OK?. Thanks for your reply!

WADR, I still don't understand your diagrams with the "Unknown Connections" on all of them. Further confusing it now is your report that you have three red switches.

We simply all seem to be having difficulty understanding both what you're showing and what you have, so I suggest you consider going back to my reply #3. You NEED to trace the wires on your boat, 'cuz all the diagrams and all the switches in the world and all the questions here on the internet won't do that for you.

Somebody changed something(s) on your boat and you need to find out what it/they was/were.

It would be odd for the alternator output (AO) to go to a switch, because the very last thing you want to do is interrupt the AO which fries the diodes.

The OEM two large red switches were "use" switches: which battery got used for loads.

[edit to add:] Also, when I open the PDF files, the wires between the components is hard to see against the graph paper lines, really, really hard to read.

 

[Ron20324]

Might the "unknowns" go to a windlass or inverter? If a charter boat, i'd say windlass... but still this looks unusual. I'm going out to work on our parade of lights boat, so will spend more time on the forum this evening.

 

[Ron20324]

I must say I'm with Stu and the others. Your 3 schematics have unknowns, and we can not totally suggest what to do since we and you don't know what you have - even on your desired 'final'. To assume your boat is similar in equipment to what I have, we B's have a good switch system, though others will think otherwise. I've added alot of equipment in the 8 years I had her, and working off the basic Beneteau design, it has worked very well for me. I just drew up a schematic to the best of my recollection as the details are on the boat.

Your 'final' shows a switch between the radio/bilge, plus a switch on the "motor"- whichever motor you mean. I really have to assume you have a circuit breaker panel that should have the macerator and radio/bilge wired through breakers. Of course there would be an "always on" feed to both of these devices and there should be no switch, just fuses.

You have two batteries, which is what my OEM was, but I added a third- all group 31s. The nice part of this system is you can turn on or off any combination of batteries to use the juice or to recharge them or isolate a bad one. You can switch on either one and read the voltage on the panel meter, but i have a Victron battery monitor for that putpose.

I have a feeling where your "macerator"is, was originally a black one for disconnectiong battery grounds. I had a black one, but rewired it when I added the Victron, then swapped the black for a red for the third battery. (It could have been just painted, and maybe yours is?)

If your batteries are wired as I think they are- or SHOULD be- straight to the switches, the switch would serve the same purpose as the SBH switch you added on your final, and you would not need it.

I would point out it is not possible to charge any battery when it's switch is not connected to the positive buss. Thus far I have not needed to do that, though to do so, I could switch it "on" once the engine has started on some other battery. At anchor overnight or on shore power I always have one battery off line, as "reserve" if you want to call it. With two batteries, I would alternate them as to starting purposes.

ANY of the 2-3 batteries can be used for power, and be charged, when it is switched on. I think this covers it, but maybe more thoughts will become as you pursue your boats wiring system. For clarity, I have not drawn in the necessary fuses. That is another rmatter, but important

 

[SeisNudos]

FINAL Battery Wiring

I have taken into consideration some of your suggestions and I have come up with the attached diagram.

1 - Basically what I have done is to keep the Red Switches in the on possition and select which battery I want to use to start the engine. I will use the Red Switches when mooring the boat.

2 - I have attached a battery isolator so that both batteries (Groups) will be charged when the engine is ON. Now I can monitor each battery with two battery meters.

3 - If I want to add another House battery, all I have to do is wire it in parallalel to the one thats there.

Thank you all!