fusing a 450 Ah bank

[Stu Jackson]

Originally Posted by mariner36bob

I dont want to have to go below to switch after starting. I'd like to turn the key and have start batt. start the boat. But at same time have bank 1 power the house. A combiner can charge the start I understand.

To do this i have to remove bank 2 from the 1/2/both switch and make it's own starter loop with it's own switch, right?

Could this be accomplished and maintain capability of house bank (not in the aforementioned starter loop) to also start the boat (as a back up)?

Try these, answers your questions. Your boat, your choice.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

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

[mariner36bob]

Ayuh, those links pretty much squared me away.
If there's not a book deal in your future, there should be.
p.s. I like picture books the most.

[jongleur]

Okay, I've read MaineSail's treatise and I'm just
not able to figure out what the orange line from #1 to
the C post is. A little help here?

[mitiempo]

Originally Posted by jongleur

Okay, I've read MaineSail's treatise and I'm just
not able to figure out what the orange line from #1 to
the C post is. A little help here?

Which wiring diagram? Can you post it or at least link to it?

[jongleur]

Here's the link from Stu Jackson's post above:

1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

[jongleur]

Sorry. It didn't post as a link.

[mitiempo]

The orange line represents the current path when the switch is in the #1 (house bank) position.

[Stu Jackson]

Originally Posted by mitiempo

The orange line represents the current path when the switch is in the #1 (house bank) position.

Here's why:

OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

You might want to spend some time reading these highlights of electrical systems.

Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

[osirissail]

For the OP and others, recently while eating down below I noticed smoke pouring out of my battery compartment. Further investigations revealed one smoking hot battery.

My batteries are 12VDC so each bank was wired in parallel with fuses between the bank and the battery switch. There were no fuses between each battery inside the battery bank. To stop the runaway battery I had to disconnect one of the interconnect cables between batteries. The bad battery had internally shorted and was sucking serious amperage from the other batteries.

So it might be prudent to add some "anl" fuses between each battery within a bank in addition to fusing the feed from the bank to the power distribution center. An easy way to do that is to go to Walmarts and get the battery terminal connector that has a thumb screw that holds the part that clamps to the battery post to the part where you connect the battery cable. Then an "ANL" fuse can be inserted between the parts without the need for additional fuse blocks and additional cables.

[mariner36bob]

Hi good morning, thanks for the tidbit. I would have to defer to a smarter guy than me re: fusing between the batteries in a bank. So I am definitely interested in hearing the /reply/advice. It seems like sound advice to me.

I'd be hesitant to add even more metals to the mix. I have seen that battery disconnect used on automobiles with a fused jumper bypassing the disconnect knob in order to keep radio memory.

I'd be inclined to utilize a terminal fuse block MRBF Terminal Fuse Block - 30 to 300A - Blue Sea Systems as opposed to the brass connector shown above.

[jongleur]

So, in this image, the orange line is not a wire.

http://www.pbase.com/mainecruising/image/141227041.jpg

And, the only thing needed to complete this drawing
would be an ACR between the + posts on the two
batteries, right?

Am I still missing something?

[mariner36bob]

The orange line in that drawing is the "switching action" of the 1/2/Both switch itself, not another wire.

In the drawing, the 1/2/Both switch is set to 1 hence the orange line (current path) is fed by #1 battery.

Visualize the switch set to # 2, the orange line moves over to #2 post and everything is fed by the #2 battery.

This drawing, as I understand it, shows a common utilization of the 1/2/Both switch and further as I understand it can be modified in multiple configurations.

[mariner36bob]

I've learned so much in the past week. My original plans were complete hack.

I believe based upon the information provided (for which I am very grateful) that I have now fused the house bank correctly.

This is how it fits into my overall solar/battery update for summer 2014.

Comments appreciated.

[David M]

You fuse to the ampacity of the wire and circuit length. You can fuse lower but never greater. To fuse less means you wasted wire and could have gone with a smaller gauge wire in proportion to your smaller fuse.

[evm1024]

Originally Posted by jongleur

So, in this image, the orange line is not a wire.

http://www.pbase.com/mainecruising/image/141227041.jpg

And, the only thing needed to complete this drawing
would be an ACR between the + posts on the two
batteries, right?

Am I still missing something?

You could use something like an "echo charge" with its own breaker/fuse.