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Discussion Starter #1
I asked the following question about how to wire batteries for house power using a battery switch in another thread:

Hey tip, I just bought one of those BlueSea battery switches and am planning to wire two batteries up for overnight power. Have you found a good wiring diagram on SN or anywhere else for that?

Anyone else have one?

PS - Nice work on the chainplates dude!
And then somone asked me what kind of switch I had, so this:

It's the BlueSea 6007 that I bought HERE.

It's got 3 posts - and the switch is the Off/1/2/1+2 config. The question I have regards wiring the negative terminals. Do I gang those across the 2 batteries - then go into the buss with single wire? Or what?

This is just a house bank. I have an OB so don't have to worry about a starting battery. I just need extended power for the lights, etc.

This electrical stuff is hard.

(PS - surely there's already a thread for this. I just haven't found it.)
And then I tipped my hand of flaming ignorance when asked why I needed a switch for house power...

Thanks for the advice guys.

The idea was to use the switch to go from one battery to the other as one draws down. For example, I'll use battery A during the day for the instruments, tunage, and margarita machines, then switch to battery B for cabin lights and anchor light at night. That kind of thing. Of course, that may be where I'm wrong.

The switch does have an off position. So it should be good.

And I guess I could use the 1+2 (combined setting) to gang them like Bene said above. Instead of running them single. But then that starts getting into the whole series versus parallel stuff about which I don't have a clue.

Like I said...what do I know about batteries?
And I started get some good feedback - but it started hijacking the original thread.

So I'll bring my impressive display of electrical ignorance here and learn something about batteries if you fellas don't mind...
 

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Discussion Starter #2
An reply from bene...

Smack -- Why even use a switch, if it's just for your house bank? Batteries last a lot longer if they are only partially discharged. By switching your house load to one battery, you'll have 1 deeply discharged battery instead of 2 partially discharged batteries. Deep discharge=bad thing to do.

If you have two dissimilar batteries that were bought years apart, then I could see the reasoning. Or if one is Gel and the other Lead Acid, then OK. But if you got the batteries at the same time and they are similar, then return the switch or put it on eBay, and use the money elsewhere.

(If you just bought a battery, thinking you need the switch because you have 1 old battery and 1 new battery, return the switch and get a second new battery instead and recycle the old battery.)

Those switches are pretty much for people that have a house bank and an engine bank, IMHO, not your Smacktanic.

Regards,
Brad
 

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Discussion Starter #3
And a follow-up from tap. Thanks guys.

That's not how you want to do it. The more power you use out of a battery, the harder it is on it. One at a time, you drain battery A half empty and have battery B full. Both at once and battery A and battery B are a quarter empty for the same usage. Your batteries will last a lot longer with the latter method.

You can try to switch back and forth to keep using both batteries equally. But this requires you keep track of your usage and manually switch. Do you have a good idea of how much power one hour of instruments use vs one hour of cabin lights? You're probably not going to split it very well. If you use both at once, and the two batteries are matched, your usage will automatically be split equally between the batteries.

Another thing is that the faster you draw power out of the battery, the less efficient it is. This matters most for high power things, like a blender. If you make one margarita on A and then another on B, it will drain your batteries more than if you made two margaritas using battery A+B.

You would have been fine with just a simpler on-off switch, which would be wired simpler and with less wire, but the switch you have is fine too. Just leave it set to 1+2. If somehow one battery goes bad, then you can set it to use just the other.
 

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Discussion Starter #4
If you make one margarita on A and then another on B, it will drain your batteries more than if you made two margaritas using battery A+B.
Now that's math I can understand.

I'm starting down the road of eventually adding an inline charger, etc. and might even throw in one of those fancy inverters for kicks. Of course, since I don't have a clue how this stuff works, I will try to ask questions BEFORE I purchase.

Thanks for the help dudes.
 

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1975 Newport 28
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For what it's worth, here's the drawing of my battery setup. The benefits of partial-discharge-better-for-battery-longevity aside, I decided to go with the don't-make-it-possible-to-drain-your-starting-battery-with-the-blender setup.

My house circuit draws on only one battery -- my deep-cycle -- while the starting/charging circuit can use the 1/2/both configuration. I'd rather replace a house battery once every four years instead of every three (hypothetically speaking) than forget about my switch setting and have no starting juice when I want it.
 

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Discussion Starter #10
Wow Jas - I'm going to have to study that one. One question I have concerns the ground. There is a ground and hot buss - but I'm not sure what the ground buss is grounded to (we don't have an inboard). What should it be grounded to?
 

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Wow Jas - I'm going to have to study that one. One question I have concerns the ground. There is a ground and hot buss - but I'm not sure what the ground buss is grounded to (we don't have an inboard). What should it be grounded to?
Smack you can ground it to whatever you want to ground it to, usually the ocean, but some people leave them floating.
 

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Jas – What does the “bypass switch” on the engine circuit do? Is your keyed ignition switch going out?

Smack – How sophisticated is your charging system? Do you have a means to recharge from your outboard or do you rely on shore power to do the trick? Although not the best, a voltmeter will tell you your rough battery status. Remember that for long life, you do not want to expend more than half of your battery’s capacity (in amps) before recharging. One thing that we all should do is an energy audit (I use an excel spreadsheet). Give me your battery’s storage capacity (in amps) and a list of all your electrical devices and I can help you work something up.

I’ll see if I can dig up the diagram from when I did my electrical system upgrade. You ain’t seen nothing yet! :eek: <O:p
 

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Personally, I think you'd be better off with the BlueSea Dual Circuit Plus switch.
 

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For what it's worth, here's the drawing of my battery setup. The benefits of partial-discharge-better-for-battery-longevity aside, I decided to go with the don't-make-it-possible-to-drain-your-starting-battery-with-the-blender setup.

My house circuit draws on only one battery -- my deep-cycle -- while the starting/charging circuit can use the 1/2/both configuration. I'd rather replace a house battery once every four years instead of every three (hypothetically speaking) than forget about my switch setting and have no starting juice when I want it.
As I (mis?) understand it, Smack doesn't have an engine battery, otherwise that's a great setup.

With only house a house bank, there's little reason to start dividing it up, and some good reasons not to.

I suggest returning the switch to the store, or put it on ebay, and buy some extra margarita mix. But, we really need to know more about your 2 house batteries. Are they same type and age?

Regards,
Brad
 

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One question I have concerns the ground. There is a ground and hot buss - but I'm not sure what the ground buss is grounded to (we don't have an inboard). What should it be grounded to?
Run it right back to the (-) terminals on the batteries. The ground buss is there just to consolidate all your ground wires into one place, instead of running them all back to your battery terminal.
 

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jaschrumpf

I am guessing your battery switch is a simple on/off one. Your schematic shows that your house panel is live all the time as the order is switch - battery - house panel. Both common sense and ABYC require a way to switch it off. A suggestion is to replace your switch with a 1/2/both/off switch or install a second on/off switch to enable you to cut the power to the panel.
 

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Discussion Starter #19 (Edited)
Run it right back to the (-) terminals on the batteries. The ground buss is there just to consolidate all your ground wires into one place, instead of running them all back to your battery terminal.
Now that's a nice simple answer. Thanks dude.

Bene, they are different type batteries. I have the littler one and the bigger one versions. And the littler one's label isn't a coloredy as the bigger one's. I'll have to look at them to see what the specs are. But definitely not the same.

George, right now I'm using shore power only. I have a standard 120v charger that has a variable level charge switch. I'll check the batteries' storage and let you know what we're looking at.

The main reason I added the switch is that last time we were overnighting we used the 2 cabin lights (we have 4 standard 2-lamp fixtures) and the battery drained really quickly. Then with the anchor light on overnight it killed the battery dead. Seemed like I should have had more time than that.
 

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jaschrumpf

I am guessing your battery switch is a simple on/off one. Your schematic shows that your house panel is live all the time as the order is switch - battery - house panel. Both common sense and ABYC require a way to switch it off. A suggestion is to replace your switch with a 1/2/both/off switch or install a second on/off switch to enable you to cut the power to the panel.
My battery switch is a 1/2/both/off switch. If I want to cut power to the house panel I just reach under the seat and disconnect the lead.
 
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