Bus bar

[robstrom]

In my system build (which I've posted prior), thought is a bus bar simply for negatives on the 12 volt fusebox side, rather than to the fuse panel.
Simply, to avoid clutter.
I'm using Will's idea of mounting components to a piece of plywood, w 1 exception:
12 volt fuse block/bus bar mounted separately.
Possible future removal to a fixed structure, without having to disassemble my trailer wiring at all, other than pull pos/neg off fuse block.
Simple system, only 6 DC circuits, and small fridge AC.

 

[Zil]

ST Blade Fuse Block - 6 Circuits with Negative Bus and Cover - Blue Sea Systems

Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses for electronics and other appliances.

www.bluesea.com

 

[HRTKD]

A common bus bar simplifies wiring. You can stack only so many lugs/ring terminals on a battery post.

 

[robstrom]

I have this fusebox.
A bus bar would mount next to it, for negative wire mounting??
Then, ! negative cable to battery?

 

[HRTKD]

A picture or diagram would help me understand the landscape of your system.

 

[robstrom]

Its not built yet. Checking my earlier posts should clarify.
Only component change is 600 watt Samlex inverter, rather than 350.

 

[HRTKD]

When referring to another thread, please use a link. I'm not going to chase down your other thread.

 

[Zil]

You can get help here if you ask the clear question. We can not research your prior posts.

 

[Spishblue]

A common bus bar simplifies wiring. You can stack only so many lugs/ring terminals on a battery post.

I just learned what a bus bar is while attempting to wire 4 components to my battery bank. I'm new to solar and wiring, so in my initial design, I didn't think about how 4 connectors AND a main fuse won't all be able to make proper contact together on a bolt (nor even if they ALL should in one place). I vaguely thought, "o the bolt looks long enough, I need to move on..." I read whispers of bus bars online throughout my research, I didn't bother to find out what a bus bar is until last night. Last night I finally ordered one bus bar for a couple of positive wires. Woke up this morning, then realized I'm gonna need a second bus bar for my negative wires, uh-yup.

 

[HRTKD]

I just learned what a bus bar is while attempting to wire 4 components to my battery bank. I'm new to solar and wiring, so in my initial design, I didn't think about how 4 connectors AND a main fuse won't all be able to make proper contact together on a bolt (nor even if they ALL should in one place). I vaguely thought, "o the bolt looks long enough, I need to move on..." I read whispers of bus bars online throughout my research, I didn't bother to find out what a bus bar is until last night. Last night I finally ordered one bus bar for a couple of positive wires. Woke up this morning, then realized I'm gonna need a second bus bar for my negative wires, uh-yup.

Your life is going to get easier!

It might make more sense if we called the bus bar on the battery and the bus bar we wire things to by different names. I try to refer to the wiring bus bar as the common bus bar and the other one as the battery bus bar. There there is the whole converter/charger naming.

 

[Offgrid_UpNorth]

Spishblue, I'm finding the same thing in needing the space for more wires! I'm looking to upgrade to 4 6v batteries, wired in pairs for a 12v system. I have two arrays going through two charge controllers.

Can anyone provide examples of bus bars? There are some blue sea ones, but quite a few that look like they are for small car 12v distribution--not for my solar batteries and charge controller. Should I worry about the voltage of the bus bar? If my 2000W inverter draws a max of 160A (but never will with my load), does a 150A bus bar work okay? Amaz*n doesn't have one larger than that. Ditto in what fuse to use between battery positives and bus bar. Help with suggstions?

 

[Hedges]

I'm looking to upgrade to 4 6v batteries, wired in pairs for a 12v system.

If my 2000W inverter draws a max of 160A (but never will with my load), does a 150A bus bar work okay? Amaz*n doesn't have one larger than that. Ditto in what fuse to use between battery positives and bus bar. Help with suggstions?

You plan to wire the batteries 2s2p, and feed one inverter 160A.
Each battery will only supply about 80A.
You could put a 100A fuse on each 2s string of batteries.
Connect to three studs on busbar as follows:

(12V battery) (inverter) (12V battery)

That way, battery and busbar between battery and inverter only carries 80A. Inverter's cable gets 80A from two ends of busbar, 160A total.

 

[Offgrid_UpNorth]

You plan to wire the batteries 2s2p, and feed one inverter 160A.
Each battery will only supply about 80A.
You could put a 100A fuse on each 2s string of batteries.
Connect to three studs on busbar as follows:

(12V battery) (inverter) (12V battery)

That way, battery and busbar between battery and inverter only carries 80A. Inverter's cable gets 80A from two ends of busbar, 160A total.

Thanks Hedges! I didn’t know bus bars worked that way—the order matters. I have the inverter cable fused with 200a already, so good there. Where would my two charge controllers connect? Do I need a five position bus bar? (cc) (12v) (inverter) (12v) (cc2)?

 

[Hedges]

That works.
The two CC aren't identical rating, and may not produce at the same time to they don't provide perfect balance. But they are also lower current than the inverter.

Someone posted that ABYC standards allow up to 4 terminals on a stud. Here's another reference:

Electrical Terminal Stud Count: Four and No More - boats.com

It's a bad idea to stack too many terminals on one stud. It concentrates heat, which can lead to melting. And fire.

www.boats.com

Both CC stacked on top of studs for inverter would work, and that keeps charge and discharge currents from the two battery strings symmetric.
Buying a 5-stud busbar would keep the terminals separate for now, and allow additions later.
I got a busbar that has standoffs on the end, space for cables top and bottom (bolts through holes rather than studs) and I connected one battery, four inverters.

Use fuses for charge controllers two. Maybe BRBF would be convenient.
Usually the concern is having a fuse adequate to interrupt short-circuit current of the battery, but since yours appear to be lead-acid not lithium, several fuse types have good enough rating.