Battery Ground Switch

[NICK1951]

Maine,

My 1995 Beneteau Oceanis 400 has 4 battery switches (on/off only). They control the positive connections for the windlass, house, and start battery, the 4th switch is a common ground. I usually open all the switches when I leave the boat. Should I consider closing the common ground when not using the boat? Thanks.

Nick

 

[cygnussailor]

Maine,

My 1995 Beneteau Oceanis 400 has 4 battery switches (on/off only). They control the positive connections for the windlass, house, and start battery, the 4th switch is a common ground. I usually open all the switches when I leave the boat. Should I consider closing the common ground when not using the boat? Thanks.

Nick

I have two priorities when I am not on my boat. 1...the batteries stay charged, so each battery must be connected to the smart charger and 2...the automatic bilge pump must be able to work if necessary. Depending on how your boat is wired you may need to leave the common ground switch closed. As long as those two conditions are met I don't see any reason it should matter if you leave the common ground on or off. Yours is the first boat I have heard of that has a switch to open the common ground. Does your owners manual say what the purpose is for that switch?

 

[Ron20324]

.....Yours is the first boat I have heard of that has a switch to open the common ground. Does your owners manual say what the purpose is for that switch?

Alot of Beneteaus have that ground switch, but not sure why. I recall someone said as a safety feature so the the engine does not start when being serviced. I took that switch out and put in a red one for the third battery install. If you wired your bilge/battery monitor/radio on the battery side of the switches, then you could turn all of them off.

If the ground switch was somewhere obscure, it could be a good theft prevention.

I'd say if you turn them off/on all the time you leave, you are just wearing out the switches needlessly. A friend would turn her car off, then the radio, also. She could not comprehend that the radio was already off, and that she was just wearing out the on/off switch. Different strokes, etc.

 

[galynd]

What about in the case of lightning. Any advantage in turning off Ground and/or Positive switch? I have the same 3 switch setup.... 2 + switches, 1 neg switch.

 

[Maine Sail]

Maine,

My 1995 Beneteau Oceanis 400 has 4 battery switches (on/off only). They control the positive connections for the windlass, house, and start battery, the 4th switch is a common ground. I usually open all the switches when I leave the boat. Should I consider closing the common ground when not using the boat? Thanks.

Nick

Nick,

Like anything, it all depends how it is wired. Just leave the negative circuit on is the best answer..

Switching the negatives does not meet US ABYC standards and a fair number of Bene & Jenneau owners have replaced the negative switch with a red positive emergency parallel switch making a: House Switch - Emergency Parallel Switch - Start Switch configuration.

 

[dtalent]

i have a 2000 36CC. Same battery switch setup, 2 positive, 1 negative or ground. I included a pic of the back side of the positive battery switches. It doesn't matter if I turn one or the other off, there's a jumper that connects the two switches. I tested it, turn one off, I can crank the engine, turn it back on and turn the other off, I can crank the engine. I bought this boat 2 yrs ago, previous owner didn't do anything to the wiring. He was the 2nd owner and bought the boat when it was two years old. This matches the Beneteau schematic. I wish someone would tell me why its connected this way. I believe in, if it aint broke, don't fix it and so far, all systems are good!

 

[Ron20324]

...I wish someone would tell me why its connected this way. ...

Perhaps the starter is wired right off the alternator, and not through a switch or the pos buss?

 

[weinie]

i have a 2000 36CC. Same battery switch setup, 2 positive, 1 negative or ground. I included a pic of the back side of the positive battery switches. It doesn't matter if I turn one or the other off, there's a jumper that connects the two switches. I tested it, turn one off, I can crank the engine, turn it back on and turn the other off, I can crank the engine. I bought this boat 2 yrs ago, previous owner didn't do anything to the wiring. He was the 2nd owner and bought the boat when it was two years old. This matches the Beneteau schematic. I wish someone would tell me why its connected this way. I believe in, if it aint broke, don't fix it and so far, all systems are good!

I'd remove all the wires from the ground switch and attach them to a single ground bus.
Then "cut" that "jumper" wire and connect one side to each side of the now empty black switch above.
Now you can run the starter off the starter battery, the house off the house battery, the starter and the house of the starter battery, the starter and the house off the house battery, or starter and house off both batteries at the same time.

My new jeanneau is wired just like yours but without that "jumper" wire. I plan to modify it by adding the "jumper" but using the black ground switch as shown in the attached diagram.

 

[marian]

dtalent So you can select house or starting battery and have power to everything. I keep the starting battery switch off all the time. Start and run from house bank. Keep starting battery for emergence start only. Your charger should bee set-up too charge both banks even when one positive switch is turned off.

Marian

 

[Jackdaw]

a fair number of Bene & Jenneau owners have replaced the negative switch with a red positive emergency parallel switch making a: House Switch - Emergency Parallel Switch - Start Switch configuration.

That.

Combined with an ACR. Golden.

 

[dtalent]

Perhaps the starter is wired right off the alternator, and not through a switch or the pos buss?

If I turn both pos switches off, the starter doesn't crank.

 

[dtalent]

dtalent So you can select house or starting battery and have power to everything. I keep the starting battery switch off all the time. Start and run from house bank. Keep starting battery for emergence start only. Your charger should bee set-up too charge both banks even when one positive switch is turned off.

Marian

I believe the way this is setup, I'm drawing current from both house and start batteries. I want to isolate the house batteries but then I need to determine how to charge them. I have an on-board charger when I'm connected to shore power, charges all three batteries. If I separate the batteries, then the alternator will only charge...the start battery(?), I would hope. And then when I am on shore power, the charger will only charge the house batteries. Does this make sense?

 

[dtalent]

what is an ACR?

 

[kappykaplan]

Automatic charging relay. Here's a link to the Blue Sea website that explains the function of an ACR:

https://www.bluesea.com/articles/1366

 

[weinie]

I believe the way this is setup, I'm drawing current from both house and start batteries. I want to isolate the house batteries but then I need to determine how to charge them. I have an on-board charger when I'm connected to shore power, charges all three batteries. If I separate the batteries, then the alternator will only charge...the start battery(?), I would hope. And then when I am on shore power, the charger will only charge the house batteries. Does this make sense?

Do you have a factory installed isolator... the new ones at bene/jene look like this guy:

It takes the alternator current and lets each battery bank drink from it at the same time. It's kinda like the ACR but functions differently.