What is this?

Rabe

.
May 15, 2019
78
Hunter 33 - Cherubini Port Clinton, OH
Saw this today as I was removing my batteries.

The center is a negative cable, but the other terminals are positive cables.
 

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May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
I agree it looks like the layout for a battery isolator. But the wire colors all seem wrong. Black and red shouldn’t be on the same isolator, much less the same terminal.
 
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Jan 1, 2006
7,040
Slickcraft 26 Sailfish
I had one on my Slickcraft. Never really understood what it did. I posted a pic and Mainesail posted "Get rid of it." Then life took a 180 and I never did.
 

Rabe

.
May 15, 2019
78
Hunter 33 - Cherubini Port Clinton, OH
I agree it looks like the layout for a battery isolator. But the wire colors all seem wrong. Black and red shouldn’t be on the same isolator, much less the same terminal.
The black in the middle is negative. The blacks on the outer terminals just go to the battery switch.

The middle goes to the alternator and is presently black, but I think it should be red as the alternator ground is the motor not a cable, so the only thing this could be is the positive output of the alternator.
 
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Jun 5, 2010
1,107
Hunter 25 Burlington NJ
Two things:
1. Rewire this; as the green color is enough to tell me that it’s working nowhere near capacity and especially on an isolator you don’t want dodgy connections.
2. When you do rewire it, use the correct ABYC wire code with red as positive and yellow as negative for 12VDC circuits. Red-and-black was used through the 1980s and is today reserved cars, people with boats who don’t know (or care) about the current code, and nearly all motorboaters. If you have any white-and-black 115VAC circuitry nearby, this could become dangerously confusing. (This accounts for the disastrous state of many motorboats’ wiring.). Also ALL electrical wiring in a yacht should be marine-grade tinned-copper, which resists that greenish tendency for much longer. Try not to use SS nuts and washers either but acquire brass or nickel-brass, or for on battery terminals copper or nickel-copper (McMaster-Carr carry them). This too will encourage longevity.
 
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Rabe

.
May 15, 2019
78
Hunter 33 - Cherubini Port Clinton, OH
Is an isolator necessary? There's a perko off/1/all/2 switch and the charger is for multiple batteries and is wired to each battery on separate charging circuits.
 

Rabe

.
May 15, 2019
78
Hunter 33 - Cherubini Port Clinton, OH
Two things:
1. Rewire this; as the green color is enough to tell me that it’s working nowhere near capacity and especially on an isolator you don’t want dodgy connections.
2. When you do rewire it, use the correct ABYC wire code with red as positive and yellow as negative for 12VDC circuits. Red-and-black was used through the 1980s and is today reserved cars, people with boats who don’t know (or care) about the current code, and nearly all motorboaters. If you have any white-and-black 115VAC circuitry nearby, this could become dangerously confusing. (This accounts for the disastrous state of many motorboats’ wiring.). Also ALL electrical wiring in a yacht should be marine-grade tinned-copper, which resists that greenish tendency for much longer. Try not to use SS nuts and washes either but acquire brass or nickel-brass, or for on battery terminals copper or nickel-copper (McMaster-Carr carry them). This too will encourage longevity.
Doesn't ABYC specify yellow or black as the correct color for negative?
 
Jun 5, 2010
1,107
Hunter 25 Burlington NJ
Is an isolator necessary? There's a perko off/1/all/2 switch and the charger is for multiple batteries and is wired to each battery on separate charging circuits.
The isolator is generally used in the presence of a generator; but that’s not my area of expertise!

What I will recommend is getting rid of the ‘1/both/2/off’ switch. That thing has been the source of more confusion and loss of good batteries than anything else. Given a house and an engine-starting bank, LEAVE THEM SEPARATE. Any combining, on the ‘both’ circuit, of different-type, different-size, different-age, differently-charged batteries will effectively kill the weaker of the two.

There is no sensible reason on a well-designed cruising boat to combine the engine bank and the house bank except in some emergency, for which a separate circuit can be rigged and manually/mechanically connected such as to run bilge pumps off the engine battery (with the engine already running) or to start - for only one foreshortened leg of the cruise - the engine from the house. For ALL charging and discharging they should always be separated.

Modern ‘smart’ chargers can facilitate charging of two separate banks without electrically combining them. So, in answer to your question, maybe you don’t need the isolator at all.

My system is just like what I recommend to others. I was told by my cousin Rick, the family ABYC electrical tech, that I don’t need the isolator and so I don’t have one.

 
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Jun 5, 2010
1,107
Hunter 25 Burlington NJ
Doesn't ABYC specify yellow or black as the correct color for negative?
Yellow is ‘strongly encouraged’ by ABYC and BOATUS as it is the modern accepted standard on the manufacturing, components, and service ends. You will still get motorboat-minded troglodytes who will insist on using black as ‘that’s how we always did it’. But as I said that’s an automotive/outboard-boat mentality and once you get into 115VAC, air cons, gensets, battery chargers, solar arrays - which none of those caveman boats have - the importance of yellow is self-evident.
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
There really is quite a lot of disinformation in this quoted post. I'll let Maine Sail comment on it:

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

Isolators are 1980 technology, replaced by VSR (voltage sensitive relays). Or the B on a 1-2-B switch when charging sources are present. There is NOTHING WRONG with a 1-2-B switch design, one just needs to know how it is wired and how to use it properly.

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

Multiple charging outputs from shorepower chargers don't answer the proverbial question of what to do with a single output alternator, do they? That's where a 1-2-B switch B position when charging or a VSR comes in handy.


The isolator is generally used in the presence of a generator; but that’s not my area of expertise!

What I will recommend is getting rid of the ‘1/both/2/off’ switch. That thing has been the source of more confusion and loss of good batteries than anything else. Given a house and an engine-starting bank, LEAVE THEM SEPARATE. Any combining, on the ‘both’ circuit, of different-type, different-size, different-age, differently-charged batteries will effectively kill the weaker of the two.

There is no sensible reason on a well-designed cruising boat to combine the engine bank and the house bank except in some emergency, for which a separate circuit can be rigged and manually/mechanically connected such as to run bilge pumps off the engine battery (with the engine already running) or to start - for only one foreshortened leg of the cruise - the engine from the house. For ALL charging and discharging they should always be separated.

Modern ‘smart’ chargers can facilitate charging of two separate banks without electrically combining them. So, in answer to your question, maybe you don’t need the isolator at all.

My system is just like what I recommend to others. I was told by my cousin Rick, the family ABYC electrical tech, that I don’t need the isolator and so I don’t have one.

 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
Is an isolator necessary? There's a perko off/1/all/2 switch and the charger is for multiple batteries and is wired to each battery on separate charging circuits.
:plus: For what Stu said. You want some way to charge the multiple banks from the alternator, but you can achieve that either with The 1-2-B switch or a combiner. The switch is a manual process so a little more error prone - you could accidentally leave the batteries connected when discharging, or accidentally switch “off” when the engine is running, so an automatic solution is a little better in that sense. A voltage drop free combiner like a Blue Seas ACR is better for charging than an old style diode isolator.

As for the wiring color, switching to yellow would be ideal, but I wouldn’t go through the trouble of changing everything. I would fix the black wires going to the switch carrying +12V, especially since the terminals look somewhat corroded anyway.
 
Jun 5, 2010
1,107
Hunter 25 Burlington NJ
The biggest problem with the 1-Both-2-Off switch is the ease it permits the user to set it to ‘Both’ for charging ‘just for a little bit’ two dissimilar banks of batteries, which as I still maintain is a recipe for battery failure. The best practice is to have two separate On-Off switches on the load ends and to permit the alternator access to only one bank at a time, or two, duly separated, for charging.

The ONLY benefit to the 1-Both-2-Off switch (note the order in which I list those circuits) is that it permits switching through active circuits (the ‘Both’ setting) when changing from ‘1’ to ‘2’. But this is good ONLY when the switch is of a make-before-break configuration; and I know Perko has made at least one series of their very common switch that is break-before-make; which would shut down everything for a moment whilst switching (like the headlights-parking lights switch on my wife’s old Opel).

I think some are confused by thinking that the 1-Both-2-Off switch is used on charging circuits, as is too often done on small motorboats. In my experience a yacht’s battery charging is done before this switch, which is meant only for the load side (selecting between demands on the banks, vis.: house or starting). On my boat the solar array, the alternator, and the shore-power charger can all do their charging duties no matter how the load switches are set - in fact I prefer to charge at the dock with the house bank turned OFF.

Modern smart chargers and alternators can apportion the charging input to various banks without wrongly combining dissimilar banks. See the Blue Sea Systems site for further enlightenment. .
 
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May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
On my boat the solar array, the alternator, and the shore-power charger can all do their duties no matter how the load switches are set - in fact I prefer to charge at the dock with the house bank turned OFF. Modern smart chargers and alternators can apportion the charging input to various banks without wrongly combining dissimilar banks. See the Blue Sea Systems site for further enlightenment. .
What alternator are you using that allows independent charging of two banks? I presume you mean using something like a Blue Seas ACR to automatically combine the batteries when the alternator is charging. If so that’s essentially the same as a 1-2-B switch but automatic.

With regard to charging dissimilar banks, Maine Sail puts the following criteria for acceptable uses of ACR’s. When charging (not discharging) the same criteria should apply to 1-2-B switches. From Making Sense of Automatic Charging Relays - Marine How To :
If both banks can be charged within 0.1V to 0.2V of each other, an ACR is a fine choice
Same Chemistry & Same Charging Voltages = √
Same Chemistry & Very Similar Charge Voltages = √
*Mixed Chemistry & Same Charging Voltages = √
*Mixed Chemistry & Very Similar Charge Voltages = √
*Excludes mixing lead acid and Li-Ion batteries
 
Jun 5, 2010
1,107
Hunter 25 Burlington NJ
Note these solutions do not rely upon hard ‘mechanical’ connections. The ACR is an evolving technology that I like a lot - for charging and combining loads.

On Diana the solar array charges the house bank only, the engine charges the engine bank only, and the shore-power charger charges both proportionately. So I have no need for ‘1-Both-2-Off’.;)
 
Jun 5, 2010
1,107
Hunter 25 Burlington NJ
I have since received education about the solar-charging controller that renders a bit of what I said about Diana’s system a little out-of-date. After a really valuable phone call with the tech, Ryan, at Blue Sky Energy, I have been able to connect the engine-start battery to the 2-amp ‘trickle’ output of the controller, which is exactly what that feature is for. Now both banks are perpetually happy being charged by the solar array, kept electrically separate and both more than nominally healthy, typically over 13.2 and often over 13.6, all the time. I have not plugged into the 115VAC or needed to run the onboard charger since the boat’s been in the water.

So, thanks to this very excellent solar-charge controller, I have two completely separate banks maintained fully charged with NO need for any kind of combiner (nor any 1-BOTH-2-OFF switch), a setup I would strongly encourage anyone else to investigate.
 
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