Battery Switch Wiring

[Rustic Charm]

Hi all (again)

I'm putting my boat back together after engine overall and painting of bilge. Replacing most of the wiring for tinned wiring too. Now, I forgot to pay a lot of attention as to how the battery switch was wired up. It's one that has three terminals on the back (1, 2 and common) and on the front, Battery one, Battery two, Both and Off.

My system is a 12v. It has six 200ah batteries for house and one single battery for engine.

My question - Am I correct in thinking, that I hook 1 and 2 up to the individual battery banks (e.g engine and house), and the common goes to the switch panel?

If this correct, do I hook up the live cable to the starter motor to the same post as the engine battery on the switch? e.g 1. Will this (when the engine is running) then charge the house batteries if I put the switch on e.g 2 house? Will it charge the engine if I put it on e.g1 engine? Will it charge both if I put it on both?

Is this too complicated without a diagram?

Thanks. Ted

And if this is correct, where do I hook up the solar panel wires? Do they go to the post and neg terminals of the house battery bank?

[btrayfors]

Ted,

A wiring diagram would help.

You said you have six 200AH batteries for the house bank. Really? 1200AH capacity on a 35-footer? Do you mean six 6-volt golf cart batteries in series/parallel, giving you 600AH total capacity?

How to wire the battery switch has been discussed ad nauseum on this and other boards. There are lots of opinions.

The preferred way is to wire ALL charging sources to the house batteries, then use a combiner or, better, a voltage-follower device like an EchoCharge or DuoCharge to maintain the start battery. This way, there's no need to switch anything...the batteries are maintained automatically.

Here, again, is the way I like to do it on client's boats...



Bill

[Exile]

Originally Posted by btrayfors

Ted,

A wiring diagram would help.

You said you have six 200AH batteries for the house bank. Really? 1200AH capacity on a 35-footer? Do you mean six 6-volt golf cart batteries in series/parallel, giving you 600AH total capacity?

How to wire the battery switch has been discussed ad nauseum on this and other boards. There are lots of opinions.

The preferred way is to wire ALL charging sources to the house batteries, then use a combiner or, better, a voltage-follower device like an EchoCharge or DuoCharge to maintain the start battery. This way, there's no need to switch anything...the batteries are maintained automatically.

Here, again, is the way I like to do it on client's boats...

Attachment 41790

Bill

Bill -- Two questions re: your wiring diagram, from the neophyte that I am:

1. It looks like the alt is wired in to the opposite end of the fuse from the house batt. Why not directly to the batt's pos terminal?

2. Your ON-OFF for the eng start batt is to be used to start the eng only; it need not be switched ON to allow this batt to charge since that is being done by the echo -- correct so far? If so, how is the emerg jumper switch activated, presumably so that the house bank can be used to start the eng in the event of a dead start batt? If not needed, I would think you'd want to isolate the house bank from eng starting.

Thanks,
Dan

[Rustic Charm]

Originally Posted by btrayfors

Ted,

A wiring diagram would help.

You said you have six 200AH batteries for the house bank. Really? 1200AH capacity on a 35-footer? Do you mean six 6-volt golf cart batteries in series/parallel, giving you 600AH total capacity?

How to wire the battery switch has been discussed ad nauseum on this and other boards. There are lots of opinions.

The preferred way is to wire ALL charging sources to the house batteries, then use a combiner or, better, a voltage-follower device like an EchoCharge or DuoCharge to maintain the start battery. This way, there's no need to switch anything...the batteries are maintained automatically.

Here, again, is the way I like to do it on client's boats...

Attachment 41790

Bill

Yes, I have six 200ah house batteries.. why is this so strange?

Does an Echocharge operate to charge when at sea, e.g when you don't have another charging device other than a solar panel or running the engine?

[btrayfors]

Good questions, Dan...

Originally Posted by Exile

Bill -- Two questions re: your wiring diagram, from the neophyte that I am:

1. It looks like the alt is wired in to the opposite end of the fuse from the house batt. Why not directly to the batt's pos terminal?

The positive charge wire (cable) from the alternator needs to be fused at the battery end in order to avoid a catastrophic situation should a direct short develop, and to be compliant with ABYC specifications.

2. Your ON-OFF for the eng start batt is to be used to start the eng only; it need not be switched ON to allow this batt to charge since that is being done by the echo -- correct so far? If so, how is the emerg jumper switch activated, presumably so that the house bank can be used to start the eng in the event of a dead start batt? If not needed, I would think you'd want to isolate the house bank from eng starting.

Yes, the EchoCharge will provide a charge whenever it senses a charging voltage (above about 13.0VDC) on the house batteries. It will do this irrespective of the position of the switches.

The main battery switch is normally left in the #1 position. When using the house batteries for emergency engine starting, this switch is put in the "BOTH" position, and the start battery switch can be on or off depending whether or not you wish to isolate the start battery.

Thanks,
Dan

Bill

[Rustic Charm]

I'll write up a dia tomorrow and see if that makes sense. I think it was the way my vessel was wired before I pulled it apart.

[btrayfors]

Originally Posted by tedsherrin

Yes, I have six 200ah house batteries.. why is this so strange?

If, indeed, you have six 200ah 12VDC batteries in parallel, this would total 1200ah total capacity. This is indeed strange for a 35-foot boat....way more than most boats in this size range have. If they're not 12VDC batteries but rather 6V batteries in series/parallel, this would total 600ah capacity @ 12VDC and would be more in line with what most boats of this size have.

Does an Echocharge operate to charge when at sea, e.g when you don't have another charging device other than a solar panel or running the engine?

Yes. The EchoCharge will operate whenever the voltage exceeds 13.0 VDC, irrespective of where that voltage is coming from....solar, wind. generator, etc.

Bill

[Pete7]

Originally Posted by tedsherrin

Yes, I have six 200ah house batteries.. why is this so strange?

He asked the question because a 1200 AH bank on a 35ft yacht is huge and therefore very heavy and costly. If its there, working well and fitted then fine but next time you want to change the batteries you might want to do an audit to see how much you really need and therefore save some weight and dollars. The other thing is its all very well having that capacity but if you use it then how are you going to replace it?



Pete

[Exile]

Originally Posted by Exile

Bill -- Two questions re: your wiring diagram, from the neophyte that I am:

1. It looks like the alt is wired in to the opposite end of the fuse from the house batt. Why not directly to the batt's pos terminal?

2. Your ON-OFF for the eng start batt is to be used to start the eng only; it need not be switched ON to allow this batt to charge since that is being done by the echo -- correct so far? If so, how is the emerg jumper switch activated, presumably so that the house bank can be used to start the eng in the event of a dead start batt? If not needed, I would think you'd want to isolate the house bank from eng starting.

Thanks,
Dan

Bill -- I couldn't figure out how to also quote your responses to the above but I did understand them!

Re: no. 1 -- The fuse requirement at the pos batt terminal would be the same for a 110v charger. So effectively, the alt is wired to the pos terminal, albeit through a fuse. I've been trying to do some labeling on my own boat with the ultmate goal of creating a wiring diagram but can't yet see where the alt wires come into the batts.

Re: no. 2 -- Got it. In your wiring set-up, can the start batt also be used to supplement the house bank (whether that's advisable or not), or is additional switching needed?

Back to the OP, and FWIW, 1200ah is about double the capacity my 47'-er has, and it's pretty loaded up with DC appliances.

Dan

[btrayfors]

Originally Posted by Exile

.....

Re: no. 1 -- The fuse requirement at the pos batt terminal would be the same for a 110v charger. So effectively, the alt is wired to the pos terminal, albeit through a fuse. I've been trying to do some labeling on my own boat with the ultmate goal of creating a wiring diagram but can't yet see where the alt wires come into the batts.

Re: no. 2 -- Got it. In your wiring set-up, can the start batt also be used to supplement the house bank (whether that's advisable or not), or is additional switching needed?
.....
Dan

Dan,

Yes, the battery charger should also have a fuse. But, it should probably have it's own, because the fuse should be sized just a bit larger than the maximum charger output.

The alternator fuse may or may not be separate, depending. The fuse shown in my diagram needs to be large enough to handle starting current in case the house batteries are used for starting the engine. So, it must be pretty large....200A or more. If the alternator is a big one and has big cabling, this size fuse may OK. If not, it should have it's own fuse. However, you should choose a fuse size at least 25% and perhaps 50% larger than the alternator output in order to avoid any possibility of blowing that fuse while the engine is running, else you could damage the diodes in the alternator.

Please note that all fuses on cables attached directly to the house bank must be (not should be) ANL, MRBF, or Class-T types. These are the only ones with the requisite 5,000 amps or higher AIC rating, per ABYC specifications.

One scheme which works nicely sometimes is to run a short very heavy cable from the positive lug on the battery to a big bus with 1/4" or 5/16" studs. Then, use MRBF fuses mounted on that bus for each circuit...starting, house, alternator, battery charger, etc.

RE: not being able to see how the alternator is connected to the batteries, sometimes it's best to just start over and install new, large cabling directly from the alternator to the batteries, thru an appropriate fuse on the positive charging cable. Run new cables for BOTH positive and negative connections to the alternator....the typical grounding of the alternator case to the engine isn't the same thing, and you'll get better performance with wiring directly to the batteries.

FWIW,

Bill

[Exile]

Originally Posted by btrayfors

Dan,

Yes, the battery charger should also have a fuse. But, it should probably have it's own, because the fuse should be sized just a bit larger than the maximum charger output.

The alternator fuse may or may not be separate, depending. The fuse shown in my diagram needs to be large enough to handle starting current in case the house batteries are used for starting the engine. So, it must be pretty large....200A or more. If the alternator is a big one and has big cabling, this size fuse may OK. If not, it should have it's own fuse. However, you should choose a fuse size at least 25% and perhaps 50% larger than the alternator output in order to avoid any possibility of blowing that fuse while the engine is running, else you could damage the diodes in the alternator.

Please note that all fuses on cables attached directly to the house bank must be (not should be) ANL, MRBF, or Class-T types. These are the only ones with the requisite 5,000 amps or higher AIC rating, per ABYC specifications.

One scheme which works nicely sometimes is to run a short very heavy cable from the positive lug on the battery to a big bus with 1/4" or 5/16" studs. Then, use MRBF fuses mounted on that bus for each circuit...starting, house, alternator, battery charger, etc.

RE: not being able to see how the alternator is connected to the batteries, sometimes it's best to just start over and install new, large cabling directly from the alternator to the batteries, thru an appropriate fuse on the positive charging cable. Run new cables for BOTH positive and negative connections to the alternator....the typical grounding of the alternator case to the engine isn't the same thing, and you'll get better performance with wiring directly to the batteries.

FWIW,

Bill

It's worth a lot, as usual! Thanks for all your generous contributions to this & other sites, Bill. Seems like it's invaluable for newbies like myself as well as those who are old hands at this ( or think they are!). I have always found it better to look or sound stupid & learn something, vs. trying to act smart & staying stupid forever!

You gave me an idea to search for a bus with batt cables attached. The charger & its wiring was all done two years ago by a pro, and seems to comply with modern ABYC stds. The alts are orig (1986), however, as far as I know, and finding how they're wired to their respective batts has been a challenge.

I think I'll do some more investigation & then perhaps start a new thread with any questions. Along with creating a wiring diagram for myself & labeling, my end goal is to make better use out of a 220ah Lifeline 8D that is devoted solely to eng starting. I think I'd like to at least have the option of using it as a house batt in the event of a failure or on long passages.

Thanks again for your time & help.

Dan

[Stu Jackson]

These will give you the option of using the reserve bank for limited house loads.

One of them is like the one provided earlier.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams [added 9/21/11]

[added 1/31/2012] 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

[Rustic Charm]

Good morning all, (well is here in Australia),
My boat when I picked it up had four 200ah batteries, but spots for two more. One dead battery that looked like an audinary car battery was still in place and hooked up.. The seller even told me it was dead. Then there was a spot for another battery which battery terminals, but no battery in there. IN addition, there is a pretty decent starter battery.
I'm in the process right now of building a new battery box and I asked on this forum somewhere else and I was basically advised, have as many batteries as you have room for. So I thought, well I'll add the two empty spaces back, giving me six.
When I came down from Adelaide in Sept last year, over ten days, the four batteries (800ah) did run down rather quickly, basically by next morning after running through the night, they were pretty low.

Originally Posted by Pete7

The other thing is its all very well having that capacity but if you use it then how are you going to replace it?



Pete

Will not the engine + solar + wind gen (future) replace the power?

Again, I'm here asking because I am a complete novice. Value all your inputs. Love the article by Main Sail that Stu submitted. It's been the easiest thing for me to follow so far.

Ted

[Exile]

Originally Posted by tedsherrin

Good morning all, (well is here in Australia),
My boat when I picked it up had four 200ah batteries, but spots for two more. One dead battery that looked like an audinary car battery was still in place and hooked up.. The seller even told me it was dead. Then there was a spot for another battery which battery terminals, but no battery in there. IN addition, there is a pretty decent starter battery.
I'm in the process right now of building a new battery box and I asked on this forum somewhere else and I was basically advised, have as many batteries as you have room for. So I thought, well I'll add the two empty spaces back, giving me six.
When I came down from Adelaide in Sept last year, over ten days, the four batteries (800ah) did run down rather quickly, basically by next morning after running through the night, they were pretty low.



Will not the engine + solar + wind gen (future) replace the power?

Again, I'm here asking because I am a complete novice. Value all your inputs. Love the article by Main Sail that Stu submitted. It's been the easiest thing for me to follow so far.

Ted

Pretty much a novice here too, but running down 800ah on an overnight sail seems awfully fast. Remember that your entire house bank is only as good as your worst individual battery. So if you installed a new batt & wired it parallel as part of the same house bank, that new batt will be drawn down to the same level as whichever batt is in the worst shape. It could be that, or possibly an excessive draw from a malfunctioning appliance or possibly an inverter.

Dan

[Exile]

Originally Posted by Stu Jackson

These will give you the option of using the reserve bank for limited house loads.

One of them is like the one provided earlier.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams [added 9/21/11]

[added 1/31/2012] 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

Thanks Stu -- very helpful.

Dan