Battery Switch Help

ontherocks83 · Jul 13, 2020

I just switched my boat from 1 switch to 3 following Maine Sails' diagram. I like it for the isolation and redundancy purposes. here is a copy of his schematic.

ontherocks83 · Jul 13, 2020

No. I mean I had one and now have 3. Look at the diagram. It allows interchangability between banks.

Davidasailor26 · Jul 13, 2020

It looks like those switches have already been changed from the Beneteau original standard. The wire colors and gauges do give me some pause as far as whether it’s good to go as-is or could use some further improvement.

What are you trying to achieve by going to one switch? It’s going to be hard to build a robust system with fault isolation and redundancy with only one battery switch.

The picture ontherocks posted is a good one to consider. Also consider the recommended Beneteau specific diagram athttps://forums.sailboatowners.com/threads/one-black-and-two-red-electrical-switches.191463/post-1456512. That diagram would provide a good robust solution using the Beneteau switches.

Scott T-Bird · Jul 13, 2020

Just to clarify @ontherocks83 diagram, the emergency isolation switches are always on and only turned off if there is a fault with either the start bank or the house bank. Essentially, it is a 1-switch system that utilizes both banks, simultaneously and separately under normal circumstances (which means that you may never have a reason to use the emergency isolation switches to isolate a faulty bank). I have the DCP switch in my boat because I like using my smaller auxiliary battery as the start battery rather combining house and start loads. The diagram is a very good model in my opinion. The E-I switches are normally hidden from view in a compartment somewhere that is convenient to access because they are essentially never turned off. Your normal routine would be to go to the boat and simply switch the DCP switch "ON" and voila … both banks are operational and independent!

ontherocks83 · Jul 13, 2020

Scott T-Bird said:
Just to clarify @ontherocks83 diagram, the emergency isolation switches are always on and only turned off if there is a fault with either the start bank or the house bank. Essentially, it is a 1-switch system that utilizes both banks, simultaneously and separately under normal circumstances (which means that you may never have a reason to use the emergency isolation switches to isolate a faulty bank). I have the DCP switch in my boat because I like using my smaller auxiliary battery as the start battery rather combining house and start loads. The diagram is a very good model in my opinion. The E-I switches are normally hidden from view because they are essentially never turned off.

Good description

Stu Jackson · Jul 13, 2020

Maine Sail wrote the OEM Beneteau fix:
Beneteau Wiring Diagrams - Maine Sail's corrections - Just in case you have a friend with a Beneteau and want to help him with his snafued wiring Reply #8

One black and two red electrical switches

Going from that reconfiguration to a single 1-2-B switch or two or three switches are covered in these:

OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

1-2-B Considerations (New 2020 - Rodd finally got around to diagramming what I had done in the above link in 2009

)
1/2/BOTH Switch Considerations

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
1/BOTH/2/OFF Switches Thoughts & Musings

This is a newer primer for boat system wiring design with a thorough digram: Building a Good Foundation (October 2016)
Building a DC Electrical Foundation

*****************************
*****************************
And before you consider a DCP switch, read this:
AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries

*****************************
*****************************
All this is included in my Electrical Systems 101 topic: Electrical Systems 101

Ron20324 · Jul 13, 2020

mph, you have a good start on a good system aleady. Having one switch with all three batteries is the long way around the boathouse/barn and asking for difficulties later on. . I bought my 323 new, and have put alot of time thinking and working on all systems of the boat. I have a nice wiring diagram I'd be glas to send you, as it sounds like your setup will be/could be just like mine.

Not sure why you want only one switch, but it would be good to wire one battery to one switch. Put a large cable between the three switches to act as a +12 buss. Everything on the boat can be wired off this setup. I upped the 110 panel , added a 3rd battery, windlass, solar, inverter, more AC AND DC breakers and outlets and lights. This way, you can use any battery for any purpose. I turn off one at night and live off 2, always having one fresh for the engine.

Scott T-Bird · Jul 14, 2020

Stu Jackson said:
And before you consider a DCP switch, read this:
AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries

If you are reading only the first couple of paragraphs of that article to condemn the system, you should be reading it comprehensively. As the article explains, the DCP switch with isolation format is easily achieved by adding the 2 E-I switches for use only as necessary. This is achieved with the wiring diagram that @ontherocks83 presented so the warning against DCP doesn't hold water unless you are saying that the DCP switch as a stand-alone option is a problem. That's true, that is what the rant is about.

I think that I would summarize the DCP option vs. the Beneteau 3-switch option as follows:

Both are 3-switch installations. The difference is that under normal circumstances, to operate both banks simultaneously and in isolation, with the DCP switch, you only have to turn DCP "ON" (it is a 2-pole, 4 post assembly). With the Beneteau system, you turn 2 ON-OFF switches "ON" under normal circumstances (both switches are a 1-pole, 2 post assembly). The DCP system must have 2 emergency-isolation switches, which are normally left "ON" all the time, and one of them has to be turned "OFF" to isolate the bad bank and the DCP switch is turned to "COMBINE" in order to use the good bank to serve both operations (loads). With the Beneteau system, the bad bank is simply left "OFF" and the single emergency-isolation switch, which is normally left "OFF", must be turned "ON" in order to use the good bank to serve both operations. They are really very similar systems to provide simultaneous operation and isolation, with the ability to combine loads on a good battery bank when the other bank is failing.

BTW, the DCP switch is usually associated with the Blue Sea ACR. When installing the ACR, it is important to understand the significance of the "start isolation" wire that needs to be connected to the appropriate post on the starter. That's a separate issue that should also be addressed if you are using the auxiliary battery to start the engine.

Ron20324 · Jul 14, 2020

With my 3-switch arrangement, it is alot more secure to tell a crew "turn off the (left/middle/right) switch". In the home slip, after a day or two on battery or solar charger, I turn one battery OFF. I rotate turns of which is the OFF battery. This maks sure I have a reserved battery that is charged. Next time out, once under sail, engine off. When close to my sailing club's ( SOS ) raft site, I turn that third battery on so all batts get engine-charged while waiting to enter the raftup. In the raft and for overnight, and the 2nd battery OFF, the solar continues to top off whatever the batteries need. Sunday starts it all over again. Back in the slip, 3rd batt OFF for the week.

Stu Jackson · Jul 14, 2020

Scott T-Bird said:
They are really very similar systems to provide simultaneous operation and isolation, with the ability to combine loads on a good battery bank when the other bank is failing.

Scott, the entire point of that article is the inherent fallacy of combining a bad bank with a good one when one is failing. On a sailboat, it is a really wrong way to do things, as Maine Sail pointed out in his long story about just why that's the case.

Stu Jackson · Jul 14, 2020

mph242424 said:
Thanks Ron, Can you send me your diagram?

@Ron20324 Can you send it to me, too. I'd like to include in my Electrical Systems 101 topic for future links when this comes up.
Why reinvent the wheel?
Thanks, Stu

Scott T-Bird · Jul 14, 2020

In practice, I'm sure it is simple to juggle the usage and charging of batteries like that. I also suppose that it may be more re-assuring. With DCP and the correct installation of 2 (hidden) E-I switches, there is no need to perform that juggling act. The skipper or crew simply turns DCP to the "ON" position every time you go to the boat. There is nothing more to do or think about. Charging and battery usage is automatically coordinated in the manner that you desire. The only thinking that you have to do is in an emergency situation when there may be a failed or shorted battery or battery bank or something else really serious. That is also very simple. You go to your hidden location and turn the appropriate selector switch to "OFF" for the battery or bank that has failed (you should label the switches so there is no confusion if you are telling the crew which one of the two to turn off). Then you turn your DCP switch to "COMBINE". There, done. The failed battery or bank has been disconnected and your good battery bank handles all loads. The 2 banks have never been cross-contaminated and everything is hunky dory. What could be simpler?

Scott T-Bird · Jul 14, 2020

Stu Jackson said:
Scott, the entire point of that article is the inherent fallacy of combining a bad bank with a good one when one is failing. On a sailboat, it is a really wrong way to do things, as Maine Sail pointed out in his long story about just why that's the case.

Actually, the point of the article was to describe how the DCP switch must be installed in a system to provide isolation and so that a bad bank is never combined with a good bank. I agree, when the DCP is stand alone, it does not provide the isolation when the switch is turned to "COMBINE", which is what the rant was about. The simple solution was also very well documented.

Similarly, the failing of a stand alone "1 + 2 + Both" switch is that it does not provide the functionality of the DCP switch, while it also provides the same position ("BOTH") that led to the rant. Do you turn your switch to "BOTH" if you have a failed bank? Of course you don't - but your switch would perform the same crime if you did use it in that manner.

Ron20324 · Jul 21, 2020

mph242424 said:
Below you can see the battery switches on the Beneteau first 345

My Questions are as follows:

Can i go to one Battery Switch rather than the three?
If so any suggestion as to how or where to find the info?

My current configuration has two house batteries and one in the engine compartment.
I am also in the process of putting on a new shore power system as the one I have looks pretty weathered.

I am in the process of putting new BlueSea ac and dc panels in and have spent the last two weeks untangling the worst rats nest I've ever seen.
I've labeled everything possible and traced those that were not, to their source. I'm replacing all of the wiring that I can.

I have stripped the aft cabin down to the glass and want this project done before the new walls and headiner.

Thank you in advance to all....this has been a three year project for me that has finally started showing some results and I'd like not to see it up in smoke as a result of the cob-job wiring in it!

Mark

View attachment 182309 View attachment 182310 View attachment 182311

First thing I'd do is cut those bolts on the switches as short as you can to get them away from the cables.

Ron20324 · Jul 21, 2020

mph242424 said:
Thanks Ron, Can you send me your diagram?

I can't PM a .doc. I sent a PM just now asking for your email

jviss · Jul 21, 2020

Scott T-Bird said:
Similarly, the failing of a stand alone "1 + 2 + Both" switch is that it does not provide the functionality of the DCP switch, while it also provides the same position ("BOTH") that led to the rant. Do you turn your switch to "BOTH" if you have a failed bank? Of course you don't - but your switch would perform the same crime if you did use it in that manner.

With a 1-2-B-OFF switch and an engine battery disconnect you can connect anything to anything, and isolate either the house bank or the engine batt if there is a fault with either. I frankly don't "get" the DCP switch. Seems like BSS is just trying to create some new, exclusive thing.

I leave my 1-2-B-OFF in "1" always, and the engine batt disconnect closed, and just turn off the house main breaker when I leave the boat. When I'm on the boat the echo charger keeps the engine batt charged, and the alternator is connected to the house bank.