Electrical Redesign for Liveaboard

[tristanperry]

Hey everyone,

As I mentioned in a previous post link here, http://forums.sbo.sailboatowners.com/showthread.php?t=140096, I am planning a live aboard trip this summer.

One of my major preparations is for the electrical system. I am trying to find a design that would incorporate a inverter/charger and a new house battery bank. Attached to this post is the concept for my design so far, I was hoping to get some input on it to make sure that I'm not about to do something horribly wrong.

Thanks!

PS: The lines with arrows indicate AC current. Red represents positive and black for negative lines.

 

[Bad Obsession]

Question: Why do you have two "Starting Batteries?"

Stu will make sure that this is labeled correctly but the concept would be to have a larger house bank and then one battery as a Auxiliary battery.

I would wire three to do the house bank and one battery for the auxiliary. The battery switch would be switched to the house bank for the majority of the time and only switched to auxiliary to start the boat.

I am sure others will add to this suggestion as I am not a 12V guru by no means.

 

[tristanperry]

Question: Why do you have two "Starting Batteries?"

Stu will make sure that this is labeled correctly but the concept would be to have a larger house bank and then one battery as a Auxiliary battery.

I would wire three to do the house bank and one battery for the auxiliary. The battery switch would be switched to the house bank for the majority of the time and only switched to auxiliary to start the boat.

I am sure others will add to this suggestion as I am not a 12V guru by no means.

I know having two "starting batteries" is overkill in this situation . The reason I have it set up like that is because last fall I bought two new starting/deep cycle batteries. At that time it was perfect for weekend cruising and short term anchoring without shore power. So I don't really want to waste that.

I've realized now that my battery setup won't be enough for what I'm planning on doing and I would like to have two 8D sized cells for a house bank and I can't combine one of the smaller batteries with the two larger ones without destroying the smaller.

Then again, I also am not exactly the epitome of a 12V guru as well.

Thanks for the great input, I really appreciate it!

 

[Maine Sail]

A few quick thoughts..

1- What do you mean by "isolator". No one really uses them any more for many various reasons including voltage drop and the resulting under charging. A combining relay or battery to battery charger like the Echo Charger are the newer alternatives.

2- I would suggest fusing both banks within 7" of the positive post.

3- 8D's? No need for breaking your back. You'll get longer life and more cycles out of 4 6V golf cart batteries at about 66 pounds each vs about 160 pounds. As well as more amp hours of capacity they are available world wide and cost less money per Ah.. Also most commercially available 8D batteries are not true "deep cycle" batteries.

4- It can be a good option to run the alternator output directly to the house bank then let an ACR or battery to battery charger take care of the starting bank.

5- I don't really understand what you've drawn with the Inverter Charger. There should be an AC distribution panel if you have shore power. AC wiring should be Black=Hot, White=Neutral and Green=Earth/Ground.

 

[Stu Jackson]

You could start here:

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html [added 9/21/11]

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)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615

Remove the isolator and buy an echo charge for your Reserve/start bank.

I agree with Maine Sail.

Delete the connection between the alternator and starter. Wire the C post of the switch (call it 1-2-B) to the starter (and to the DC distribution panel). Run the AO to the house bank.

The I/C wire to the house bank should be red.

Show the H/N/G properly for the I/C as MS mentioned.

If V is voltmeter, suggest you replace with a battery monitor.

See: How to Wire a Battery Monitor by Maine Sail: http://forums.catalina.sailboatowners.com/showthread.php?t=125606

 

[Stu Jackson]

I/C Charger AC Wiring

This assumes you have something like a Freedom combined I/C.

These units have internal automatic transfer switches for the AC power.

Since they "replace" the incoming AC when in operation, the AC wiring goes:

--- incoming shorpeower plug
--- incoming shorepower breaker if installed if plug is more than 10' from the main AC panel breaker or optional if you want one
--- to the I/C first
--- FROM the I/C TO the AC panel main AC breaker (usually 30A)

If you don't have a shorepower breaker in addition to your AC panel main breaker, the diagram is incorrect, OR where you show "AC Outlets" you need a main AC panel breaker there and breakers downstream of that for AC onboard devices.

 

[Ron20324]

you have a 150 "W" fuse. Do you mean amps?

 

[Bill Roosa]

The battery isolator hookup is incorrect. the full alternator output goes to the battery isolator and each bank splits from there. Since they are diodes they will not allow current into the starter so you will find you have to wire the starter directly to the 3-way switch.
the isolator is a proven piece of equipment IF and ONLY IF you make sure the alternator regulator is sensing the battery voltage and not the alternator voltage before the isolator. Diodes cause a voltage drop so if you sense at the alternator you will get 14.4 - .7 = 13.6 volts after the isolator which will not charge the batts very fast. If you sense at the batteries or at least after the isolator your alternator will see the 0.7 volt drop and rase the output to 14.4 + 0.7= 15.1 to compensate.
otherwise your design looks ok, if not abreviated some.

 

[tristanperry]

The battery isolator hookup is incorrect. the full alternator output goes to the battery isolator and each bank splits from there. Since they are diodes they will not allow current into the starter so you will find you have to wire the starter directly to the 3-way switch.
the isolator is a proven piece of equipment IF and ONLY IF you make sure the alternator regulator is sensing the battery voltage and not the alternator voltage before the isolator. Diodes cause a voltage drop so if you sense at the alternator you will get 14.4 - .7 = 13.6 volts after the isolator which will not charge the batts very fast. If you sense at the batteries or at least after the isolator your alternator will see the 0.7 volt drop and rase the output to 14.4 + 0.7= 15.1 to compensate.
otherwise your design looks ok, if not abreviated some.

Thanks for all the great advice, guys. I've made some adjustments to the plan based on all of your great advice, and I've attached the new diagram. Please take a look

 

[FourPoints]

Thanks for all the great advice, guys. I've made some adjustments to the plan based on all of your great advice, and I've attached the new diagram. Please take a look

all DC negative loads should go through your battery monitor shunt, included the negative wire from the echo charger and the alternator. If they don't you will not get any reading of charging input to the batteries, only what you are drawing out of them.

If you're going to live aboard I would strongly suggest adding some solar to the mix with a solar charge controller, look at genasun controllers for anything smaller than 120W of solar.

 

[Stu Jackson]

Changes Back

Tristan, please re read my last post about the invterer/charger incoming AC wiring, you still have it backwards.

I also urge you to save $$ by buying a Victron 600 or 602 battery monitor instead of the Link. It was discussed in the link I gave you earlier. Why pay $100 extra for connecting wiring when it comes with the Victron?

It's XANTREX.

Because of the all wiring coming to your battery posts, you might want to consider positive and negative distribution posts, where all the wires come together and only one goes to each of the banks (PDP & NDP). You can use a Power Post or a bus bar for that.

Like this: Stu's Wiring Diagram http://c34.org/bbs/index.php/topic,4623.msg27335.html#msg27335

 

[Bad Obsession]

I have a link 10. I like the looks of the Victron better!

 

[mitiempo]

Tristan, please re read my last post about the inverter/charger incoming AC wiring, you still have it backwards.

Stu

What does he have wrong? The double pole main should be before the inverter. One is not needed afterwards. The inverter output is 15 amps.


I agree on the Victron but the BMV-600 is the one to buy - if the start batteries are dedicated there is no reason to worry about them. All the 602 adds is start voltage.

 

[Bill Roosa]

Or you could do it that way too.

 

[Stu Jackson]

Stu

What does he have wrong? The double pole main should be before the inverter. One is not needed afterwards. The inverter output is 15 amps.

He said he was getting a combined inverter charger, hence, my post "assuming like a Freedom 15" which has the AC coming into the inverter charger first. That's all.

In re-reviewing his second diagram, I apologize, looks right now, assuming (!) that the 30A "main breaker" is only for the shorepower inlet and that the AC Distribution Panel has its own 30A main breaker.

 

[mitiempo]

Stu

If the shorepower goes to the inverter and the inverter output feeds the boat's entire AC circuit a second 30 amp double pole breaker is not needed. There does have to be a 30 amp double pole before the inverter.

My preference is to feed a sub panel with only the loads the inverter will power, usually just outlets. In this case shorepower comes into the main panel at the 30 amp double pole. One single 30 amp breaker feeds the inverter and the inverter output goes to a separate panel with 15 amp breakers for the outlets.

 

[Stu Jackson]

Brian, as we've discussed over the years, there are many ways to wire combined I/C's,I just keep going back to my "simple" installation with our F15. It all depends on what I/C he buys and how he chooses to wire it.

That said, MS's suggestion to complete the wiring diagram with all the individual AC wires is something he really should do.

 

[Bill Roosa]

Perhaps I'm ignorant of the capabilities of the inverter charger. there can be only one connected source at a time. if the panel powers the inverter then I'm thinking that you can have both inverter on and powering the outlets and the shore power on and powering the other appliances. The rub being that the neutrals are connected AND powered by separate sources.
Perhaps I'm missing something.

 

[Stu Jackson]

Bill, the COMBINED inverter chargers have automatic transfer switches built-in. Otherwise, you're right, if they are separate they need either/or "transfer" switches.

 

[Bill Roosa]

So should not ALL the shore power go through the inverter and not just one breakers worth off the AC panel????
My reasoning (sic) is that since there cannot be two sources connected at once and the transfer switch is the device that does that function then all the shore power should go to the inverter (through the appropriate fusing of course if it is too far from the outlet) transfer switch.

This would make wiring a sub panel for "just inverter loads" imposable as in "pass through" mode the inverter would need to be wired to all the loads to power them.
Perhaps there are two AC outputs from the inverter that handle this. I'm thinking that this would be a common problem with a combined IC if they did not.