Battery Diagram

DonnyP · Jun 30, 2013

Guys,
Attached is a diagram of my batteries as setup by the PO.

Problem #1 in my system is my ongoing quest to get a qualified mechanic to actually show up and work on my generator when they say they will. So that leaves me with shore power and my battery charger or engines for now.

Problem #2 is that I really cant see how my alternators are charging the batteries??

Problem #3 Both engines are wires straight to a battery, each will start regardless of battery selector switch.

Problem #4 I'm really not sure what the switch is doing. (labeling on switch is also from PO).

Problem #5 Do I need the negative cable connecting Batt's 3 & 4? Do I need the Negative from the battery charger to the gen battery and Battery 1? Or just to Battery 1..or just to the negative bus bar on the stbd side?

Thanks in advance for answers, suggestions, questions.

The charger is an older model, 60Amp, with 3 positive legs. The alternators are Prestolite 65Amp each. Twin Ford Lehman 120HP. Onan 6.5KW gen (work in progress).

-Donny

DavidM · Jun 30, 2013

2. The engine's alternator's outputs are usually connected within the engine to the heavy starter lug and from there to the respective batteries. That is how alternator current gets to the batteries.

3/4. Correct, it looks like the selector switch controls which battery supplies the house loads.

5. All of the grounds look ok to me. You could wire the battery charger to the buss bar which in turn connects to each battery. But it works ok the way it is.

What are the blue wires from the battery charger to the alternators? Where do they connect to the battery charger?

What are the yellow wires from the alternators going out the top of the diagram.

David

DonnyP · Jul 1, 2013

Hi David,

Thanks very much. The blue wires from charger to alternator are ignition cut off (I think). The yellow wires seem to go to each helm panel (amp meter).

Would you agree that I could be running the house off the stbd batteries, run them dead, start port engine, put battery selector switch to Both, and then either immediately start or wait a bit to charge then start the stbd engine?

My issue is that when running the fridge on DC, I run that battery bank down pretty quick ~6hrs.

Brooksie · Jul 1, 2013

Your system is one of several ways to approch a 2 engine, 2 bank system. It looks like it has worked and should do what you want.

Fuses or equal are now required within 7" of the batteries in all except starter leads and would be a good addition. Blue Seas makes a terminal mount fuse that would be a quick fix. They also nave much useful & up to date info on battery systems on their site.

If you are consistantly running one bank down below the point where your engine will start, it will have a very short life especially if they are starting batteries but even deep cycle.

DavidM · Jul 1, 2013

Yes, you could operate as you suggest. And if one bank is pretty well run down it could take as much as 30 minutes for it to recharge enough to start its engine once it is paralleled with the other battery/engine. And as Brooksie noted, your batteries won't last long being treated that way.

But 6 hours??? What kind of refrigerator is it? The only kind that pull that much current that I know of is absorption types that usually run on propane but can run on DC and pull 10-15 amps.

A typical compressor refrigerator pulls about 5 amps at a 50% duty cycle and should last for a couple of days with two 12V batteries (about 200 amphours) powering it.

I would focus on the short life at anchor of your batteries. Something is pulling a lot of current or your batteries are shot.

And I don't buy your explanation of the blue and yellow wires, but that is irrelevant to this discussion.

David

Phil Fill · Jul 1, 2013

DonnyP said:
Guys,
Attached is a diagram of my batteries as setup by the PO.

Problem #1 in my system is my ongoing quest to get a qualified mechanic to actually show up and work on my generator when they say they will. So that leaves me with shore power and my battery charger or engines for now.

Problem #2 is that I really cant see how my alternators are charging the batteries??

Problem #3 Both engines are wires straight to a battery, each will start regardless of battery selector switch.

Problem #4 I'm really not sure what the switch is doing. (labeling on switch is also from PO).

Problem #5 Do I need the negative cable connecting Batt's 3 & 4? Do I need the Negative from the battery charger to the gen battery and Battery 1? Or just to Battery 1..or just to the negative bus bar on the stbd side?

Thanks in advance for answers, suggestions, questions.

The charger is an older model, 60Amp, with 3 positive legs. The alternators are Prestolite 65Amp each. Twin Ford Lehman 120HP. Onan 6.5KW gen (work in progress).

-Donny

It appears the house and the start of coming off the start battery and the battery selector switch is separating the two start batteries so the engines can not pull from the other engine battery, but on BOTH they are connected.

Usually the start and house are two completely separate battery banks, not connect except for the battery charger. Therefore the house and start can not draw from each other. The start are only connect the engines, and the house is only connect to the house.

Do you have a separate house battery bank? So where do the three red wires in the right upper corner go to, and where does the yellow wire in the left upper corner go to.

Anyway I would have two separate bank, the house and start.

Sceptic · Jul 1, 2013

Brooksie wrote

“Fuses or equal are now required within 7" of the batteries in all except starter leads and would be a good addition.”

Required by whom? The USCG? The ABYC?

Tell me where the ABYC gets the statutory or regulatory authority to impose standards on existing boats.

Fuses near batteries are a good idea, but why would you call them “required”?

As RickB has pointed out time and again - ABYC is a voluntary standard aimed at boat builders.

Mike

captrigney · Jul 2, 2013

I just replaced my original Sentry charger in my 1983 GB. It had the two extra wired labled "Ign" for ignition that came from the alternators. I'm not sure what they did. Perhaps disabled the charger during startup or when the engine was running with the charger on.

I believe mine is wired the same way as the diagram (now minus the "ign" wires). I think it is set up to select either battery as the "house" battery (no separate dedicated "house" bank). I think I would prefer the separate bank. I could then have deep cycle on the house side and a starting battery on the engine side.

bglad · Jul 2, 2013

I would suggest service disconnects on the main engine cranking circuits and other heavy loads such as windlass, bow thruster and inverter. In my local circle two each diesels and windlasses have started themselves independently but fortunately with owners present who were able to shut them down by removing or cutting cables from the batteries. Install the switches and leave them in the off position for all engines and other appliances when you are not aboard.

Phil Fill · Jul 2, 2013

The four Eagle battery banks have on/off or selector switches. When at the dock only the house bank is ON, the engines and windless are OFF.

Battery Diagram

DonnyP

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DavidM

Valued Technical Contributor

DonnyP

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Brooksie

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DavidM

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Phil Fill

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Sceptic

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captrigney

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bglad

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Phil Fill

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