Wiring question

[vtlli]

Hello there
Now I’m finish to build my 34ft steel sailing boat. Everything is done except electrical connections between engine, batteries and electrical panel.
Years ago I bought by bulk all stuff and was advised to buy splitter relay and alternator regulator. And now I scratch my head how to connect them in one system. Without them it’s so simple and I see no problems. Can someone help me with this?
This is 12 volt system. Only DC onboard.

In attachment I made the drawing with all bits with names which should be connected.

Vitaliy

[d design]

The external alternator regulator is to increase the voltage so that the batteries get a proper charge.

A splitter relay or voltage sensitive relay is used to separate the start and domestic batteries but charge them from the same source.

Someone with more expertise could draw some wires into your diagram.
Or search google for boat wiring diagram

[skipmac]

Hi Vitaliy,

I looked up the splitter relay to check the specs. I think it would be used in your system to charge the starting battery when the engine running or the battery charger connected to shore power but automatically isolate the starting battery when the charging source is disconnected.

The simplified description (leaving out a lot of little details like fuses, engine grounding, etc)

1. Output from the alternator and battery charger connect directly to the house battery bank AND to the large power connector on the splitter relay.

2. Connect from the other large connector on the relay to the starting battery.

3. Connect one of the small connectors on the relay to a circuit that is +12V only when a charging source is on. This could be a wire that is hot when the ignition switch is on and the engine running and an output from the battery charger. Do not use a circuit that is connected in some way to the house batteries or the relay will always be on, for example do not use the same battery charger wire that goes to the house batteries to connect to the small connector on the relay.

Now anytime you are charging the relay should close and charge the starting battery but when the charging system is off the relay opens and the starting battery will be isolated so you cannot accidentally discharge it to run your lights and such.

Now, when the house batteries are charging the relay closes and the starter battery also charges. When the charging

[skipmac]

They say a picture is worth a thousand words. So here's a link to a wiring diagram showing the relay to charge two batteries.

https://www.marcleleisure.co.uk/Sund...itCharge01.htm

[DeepFrz]

I like the diagrams on the Blue Sea web site.

[Dsanduril]

What Skipmac says

The difficulty will come in finding the right connection on the ignition switch to only provide 12V to the relay coil after the engine has started (as opposed to when the key gets turned). Most ignitions have a contact like this, but we need model number, etc.

Likewise for using the battery charger, does it have a separate output that could be used to power the coil? Otherwise this might need to be a manual toggle, AC relay tied into the shore power, ....

[vtlli]

Good morning Gentlemen
Thank you for your replies
Sorry for delay – I was working with diagram with your help and google. Special thanks to Skipmac.
For a moment I drew diagram which you can see in attachment.
What you think about this?
Another question: over internet (I don’t remember where exactly) few times I met suggestion to run power cables from alternator and charger to domestic batteries, not to starter one. Why? For my own opinion at any case starter battery is more important and must be charged at first.

[goboatingnow]

Originally Posted by vtlli

Good morning Gentlemen
Thank you for your replies
Sorry for delay – I was working with diagram with your help and google. Special thanks to Skipmac.
For a moment I drew diagram which you can see in attachment.
What you think about this?
Another question: over internet (I don’t remember where exactly) few times I met suggestion to run power cables from alternator and charger to domestic batteries, not to starter one. Why? For my own opinion at any case starter battery is more important and must be charged at first.

You have no way of topping up your stater battery from your mains charger

Dave


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[conachair]

Originally Posted by goboatingnow

You have no way of topping up your stater battery from your mains charger

Dave


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Can't they be paralleled to the main bank with the 1/2/both switch?

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[goboatingnow]

Originally Posted by conachair

Can't they be paralleled to the main bank with the 1/2/both switch?

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Yes but charging should not require the main switch to be in the " both" position . Alls that needed is either another diode splitter or a dual output charger.

Dave


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[dstouten]

HELP- This is along the same lines but I really need help.

I have two Optima batteries (34M @55A, 27M@66A). I wish to use these wired in parallel as my house bank and charge them both just as I did my single battery. I have been told by Optima that it will not hurt the batteries to wire them parallel but that it will suck the higher amp battery down to the lower amp (55A). I will be left with 110A for my house bank. You may ask why not just get two 27's or 34's??? Well, I bought the larger 27 and found I only had room to add another 34 battery beside that.

I am pretty ok with the above, however, when I just wired them in parallel, some wires to an older Horizon VHF and an older depth finder heated up and started smoking. Nothing was turned on and I had assumed that both of these had fuses somewhere.

Can someone tell me, what happened? Am I asking too much? I want more amperage so that when I sail overnight, my radio, chartplotter and my radar can all function through the night without draining the housebank batteries (Optimas). They will actually do that now, however, near morning, my batteries are drained.

What is my solution so that I can get more amps without burning up any more wires? By-the-way, I will be charging all of these batteries while at the marina with my regular shorepower charging system. When I am at sea, I use solar to charge the system.

[skipmac]

Originally Posted by dstouten

HELP- This is along the same lines but I really need help.

I have two Optima batteries (34M @55A, 27M@66A). I wish to use these wired in parallel as my house bank and charge them both just as I did my single battery. I have been told by Optima that it will not hurt the batteries to wire them parallel but that it will suck the higher amp battery down to the lower amp (55A). I will be left with 110A for my house bank. You may ask why not just get two 27's or 34's??? Well, I bought the larger 27 and found I only had room to add another 34 battery beside that.

I am pretty ok with the above, however, when I just wired them in parallel, some wires to an older Horizon VHF and an older depth finder heated up and started smoking. Nothing was turned on and I had assumed that both of these had fuses somewhere.

Can someone tell me, what happened? Am I asking too much? I want more amperage so that when I sail overnight, my radio, chartplotter and my radar can all function through the night without draining the housebank batteries (Optimas). They will actually do that now, however, near morning, my batteries are drained.

What is my solution so that I can get more amps without burning up any more wires? By-the-way, I will be charging all of these batteries while at the marina with my regular shorepower charging system. When I am at sea, I use solar to charge the system.

First and most urgent, if you are getting hot wires you have something wired wrong or a short somewhere. Would not matter if you had 2000 amp hours of batteries, the radio will only draw what it needs. If the wires are smoking then the electricity is going somewhere it shouldn't.

Deal with this first before you start a fire. Comments on the other questions to follow.

[skipmac]

Originally Posted by dstouten

HELP- This is along the same lines but I really need help.

I have two Optima batteries (34M @55A, 27M@66A). I wish to use these wired in parallel as my house bank and charge them both just as I did my single battery. I have been told by Optima that it will not hurt the batteries to wire them parallel but that it will suck the higher amp battery down to the lower amp (55A). I will be left with 110A for my house bank. You may ask why not just get two 27's or 34's??? Well, I bought the larger 27 and found I only had room to add another 34 battery beside that.

I may be wrong but I do not agree with what you report Optima said about different capacity batteries in parallel. First and here I am sure, low or high amp hour capacity will not suck down another battery that has higher or lower capacity. The current will move from one battery to another based on a voltage difference, not a capacity difference.

Two batteries in parallel will stay at the same voltage and I do believe both will be able to deliver their full capacity.

Since you already have the batteries I guess it's too late to change but if you could fit two Trojan T105s (6volts each) in series you would double your capacity to 225 amp hours.

[sabray]

I think Mainesails web site covers this all pretty well. A short run from house batts to a terminal strips then direct to Atn fuse. Or fused bat terminal.i like a selector switch that goes house on off engine on off and combine. Those are the small things that caught my eye along with the other po dative comments


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[vtlli]

Dstouten:

Your batteries wired in parallel shouldn’t suck down another battery that has higher or lower capacity. Look at this from another point. Any battery consists from number of cells which are wired inside of the box in parallel. So you just add more cells to your battery bank.

Another thing which is worrying me it’s your amps: 55+66=121 Amp. For safe use you can drain not more then 50% from you bank. 60amp should stay in the battery at any case. Alternatively you will destroy batteries, So, you can use another 60. Now is question: How much you can top up your batteries? Usually you are charging to 80-90% or, in your numbers, 100amp. So for the night you will have only 100-60=40amp. How much radar takes per hour? And for how long you can run it?
I had same problem on my previous Nicholson31. There was two 105amp batteries =210amp. And it wasn’t enough for all night using radar, just occasionally.

PS. I hope we are talking about domestic batteries only, and you have separete battery for the engine.