One Last Wiring Question on Alternators and Starters

Maine Sail · Feb 28, 2013

JK_Boston_Catalina310 said:
I apologize for the poor drawing but I did this real quick this morning. (it is not my entire wiring drawing, just trying to understand a specific point)

Option 1 is how I have been planning to set up my boat. But in rereading a couple of old threads I started thinking about Option 2.

I am sure there is an advantage to Option 1 but I just don't know what it is and was hoping you could help me understand it. Option 2 is easier and would still allow me to isolate both the starter and the alternator for service. Option 2 should also always allow the alternator to be attached to a battery.

I am starting, and hopefully finishing, this project this weekend. So after this post, the next should be progress photos.

Thanks,

Jesse

Why are you even adding the second ON/OFF switch?

Do you want or need a "dedicated" starting only battery that is never used for anything other than starting? You can do everything right off the house bank and keep the simple 1/2/BOTH and use it as a use only switch. I was just not aware that you desired a dedicated starting battery?

For the alt "service disconnect" you can also use a thermal breaker but be sure it is large enough.. Hell you can keep it on the "C" post too.....

If you have an ACR, and you do, the the alt should ideally go to the house bank first, the one most deeply discharged, not the start battery first.

Option 2 forces all the current for charging the house bank to go through the ACR relay, not something I would advise nor would Blue Sea Systems with drastically differing sized banks.. This can cause relay cycling when the house bank is larger than the starting bank especially with marginally sized alternators and charge sources. I some cases the relay cycling is so bad the house bank may not begin to charge for an hour or more due to the constant on/off, on/off of the relay.

If you want a dedicated start battery and don't mind replacing the main battery switch a Blue Sea DCP with two ON/OFFS (one for each bank hidden out of sight) allows manual redundancy and control in a bad situation and a simple ON/OFF the rest of the time. I still think keeping the 1/2/B is a fine approach for how you intend to cruise.

I really don't think you need a dedicated start battery, but you certainly can if you want. If you do, and use an ACR, you'd be best to route the alt to the house bank first....

Maine Sail · Feb 28, 2013

JK_Boston_Catalina310 said:
Ok, so I have gotten my head out of my a$$. Reread your post on the 1/2/Both/off switches and revised my wire diagram one final (I hope) time.

Everytime I think I understand this, I second guess my self and ask a stupid question.

Sorry and thanks.

Jesse

Jesse,

Looks great...

Bill Roosa · Feb 28, 2013

JK!!!
There is NO "RIGHT" answer!!
Start with what you want the system to do. If you have small loads and never do anything but day sail you don't need any of this stuff. just get a big battery and your set. If you are the least bit salty you can manage stuff that would require automation for the not so salty. A 3way switch is not going to blow your diodes or leave you stranded. yOU will have to miss handle the 3way for that to happen. Automation has its value but I have found that it tends to die at the least opportune moment and do so with out even making a noise or catching on fire to let you know.
alternator to starter to common on the 3-way
#1 on the 3-way to the house buss
#2 to the start buss
That is about as minimalistic as you can get. Where you go from there is up to you.
It all depends on how YOU want to use YOUR boat.

Maine Sail · Feb 28, 2013

Bill Roosa said:
JK!!!
There is NO "RIGHT" answer!!
Start with what you want the system to do. If you have small loads and never do anything but day sail you don't need any of this stuff. just get a big battery and your set. If you are the least bit salty you can manage stuff that would require automation for the not so salty. A 3way switch is not going to blow your diodes or leave you stranded. yOU will have to miss handle the 3way for that to happen. Automation has its value but I have found that it tends to die at the least opportune moment and do so with out even making a noise or catching on fire to let you know.
alternator to starter to common on the 3-way
#1 on the 3-way to the house buss
#2 to the start buss
That is about as minimalistic as you can get. Where you go from there is up to you.
It all depends on how YOU want to use YOUR boat.

Other than antiquated diode isolators, that no one uses any more, can you actually cite some examples of ACR's, Echo Chargers or Duo Chargers failing...?

These devices are some of the most reliable pieces of gear I've seen in the marine market. The Echo Charger has approx a 25 year proven history and I can't recall a single failure.

Yandina, who invented the automatic combiners, has sold thousands and thousands of them with a lifetime unconditional warranty. For a small company an unconditional warranty could put you out of business but they are still going....

I have never seen either a Blue Sea or Yandina combiner fail, nor heard of one. This is not to say they can't or won't but they have proven to be EXTREMELY reliable pieces of gear. Even in installations where the installer has the full current running through the relay causing it to cycle I've still not seen a failure. I had one customer with a 180A alt running a 120A rated Blue Sea ACR, he did so for four years and the relay still worked like the day it was installed.... I have many boats that use them and have well over 10,000 hours of charging or "combined" time on them yet still no failures...

The Duo Charger, while less popular, has also proven to be bullet proof....

So, do you have actual examples of ACR's, Echo's or Duo Charger's failing....?? If so I'd love some more info and specifics on these actual cases.....

Stu Jackson · Feb 28, 2013

Jesse, Bill always chimes in with this stuff.

If a combiner fails, AND you have your AO going to the house bank, then only WHEN CHARGING SOURCES ARE PRESENT, use the B position on the switch. Heck, you could save some $$ and NOT buy the combiner or ACR and do that manually, but why bother.

Just turn to "1" and GO.

We've kept repeating these links, but it wouldn't hurt to reread 'em.

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

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

One Last Wiring Question on Alternators and Starters

JK_Boston_Catalina310

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Maine Sail

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JK_Boston_Catalina310

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Maine Sail

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Bill Roosa

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Maine Sail

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Stu Jackson

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JK_Boston_Catalina310

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