Generator Connection to Batteries

[GeneM]

My generator alternator and starter is connected across the house battery bank and the starting battery. Those two are isolated and there is a link solenoid so they can be connected if necessary. Is that good or should I move it to just the house bank.

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[fallingeggs]

GeneM,

I don't quite get what you are describing, but let me guess: (1) The generator's alternator is connected to the house bank, (2) The starter is connected to the starter bank, (3) the house and starter banks are generally isolated, but there is a switch to combine them.

Please correct if I'm wrong. (I don't quite understand that the alt and starter are "connected across" the banks, but the banks are also isolated.) Also, where is your bank cut off switch (the 1-2-Both switch, typically)?

Notwithstanding the above, here is a quote Stu Jackson with a few links that might have your answer. Perhaps it will help determine how you are currently wired.

Originally Posted by Stu Jackson

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 | SailboatOwners.com Forums

The Short Version of the 1-2-B Switch Stuff: Electrical Systems 101 This is a link to the Electrical Systems 101 Topic, reply #2

[Privilege]

If I understand you correctly, your house and starting bank are connected to the starter of the genset. That means that the two banks are connected together which is a bad thing. Connect your genset to one battery bank and use a voltage sensitive relay to connect the two banks for charging purposes.

[john61ct]

Originally Posted by GeneM

My generator alternator and starter is connected across the house battery bank and the starting battery. Those two are isolated and there is a link solenoid so they can be connected if necessary. Is that good or should I move it to just the house bank.

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Are you saying the Generator and Alt is on House and the Starter battery only gets charged when your combining solenoid is closed?

That's fine, as long as the solenoid is in fact closed enough to make sure the Starter is getting enough charge to full. What controls the solenoid?

A voltage-sensing auto relay or Echo Charger would be better than manual or ignition switching.

More in depth:

What are your motoring patterns, what sort of Load patterns?

What charging sources other than the Alt and Generator do you use? Are they also wired to House, and are the banks then combined?

[DeepFrz]

Lets play 20 questions!

[GeneM]

OK, I have to give more details. The boat has two inboard engines where the stbd bank of 2 4D's run the house load and starts the stbd engine. There is a single 4D to start the port engine. The link solenoid combines the positives on the two banks in case either bank needs a boost. It is engaged with a remote switch manually.

There is a charger that is run by the generator that has a charging line to each bank.

I attached a drawing of what I think I should change to. I did everything but the generator. It currently has the starter-alternator positive attached to the house bank and the negative to the starting battery for the port engine. There is also a jumper connecting both banks negatives. It was wired that way when I bought it.



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[john61ct]

I'm just a noob, so maybe others can make some sense of that, but it just makes me very confused.

So I'll say just hire a pro recommended by people you trust.

Get them to make a proper diagram, maybe one showing loads only, another showing sources. If you post that with answers to the above plus other usual questions I'm sure you'll get good feedback before you actually sign off on the design.

[smac999]

I still don't understand your question. Your drawing does not show a "generator alternator"


The purpose of a generator alt is to maintain the battery that starts the gen. it should not be for charging. The ac charger powered by the generator that. The gen alt should be connected to same battery that starts it.


Your battery charger needs to be connected on the battery side of the switches. Not the load side

Also you are missing a switch and fuse on the inverter line.

Also a gen switch between battery and gen

Im also not sure what's going on with the battery switches. Is this 2 switches? Why are all 4 posts joined ?

[ericoh88]

Hi GeneM

Some genset has alternators with poor regulation which may damage your house batteries. I have disconnected mine and use the 240v to charge the house bank.

Eric