Battery wire size and fuse

[RoadTurtle]

(4) 100ah 12v batteries in parallel
Victron MultiPlus-II 2x120V Inverter/Charger (12v) datasheet link
5th wheel buss bar has 6g wires to fuse panel and also from battery charger

Assume short wire runs, probably no more than 3ish ft roundtrip.

What size wire interconnecting batteries, and then to multiplus?
What size fuse coming off battery? I'm assuming T Class?
What size fuse to trailer 12v buss bar?

What size and type fuse to trailer buss bar?

 

[sunshine_eggo]

(4) 100ah 12v batteries in parallel
Victron MultiPlus-II 2x120V Inverter/Charger (12v) datasheet link
5th wheel buss bar has 6g wires to fuse panel and also from battery charger

Assume short wire runs, probably no more than 3ish ft roundtrip.

What size wire interconnecting batteries,

2/0

and then to multiplus?

3000W/12V/.85 = 294A

https://www.victronenergy.com/upload/documents/Manual%20-%20MultiPlus%203k%20120V%20Ve.Bus%20enabled%20-%20rev%2000%20-%20EN.pdf

P.14 says 2X 50mm^2 cables which is almost 4/0

Recommend marine grade 4/0.

What size fuse coming off battery? I'm assuming T Class?

Yes. 1.25 * 294A = ~367A. Probably need to bump up to 400A.

What size fuse to trailer 12v buss bar?
What size and type fuse to trailer buss bar?

1.25X wire rating.

 

[RoadTurtle]

2/0

P.14 says 2X 50mm^2 cables which is almost 4/0

Recommend marine grade 4/0.

Please excuse my stupidity, but why can I use 2/0 between the batteries and 4/0 between the battery buss bar and Multiplus? Whouldn't they be carrying the same load?

Why does victron recommend 2x 1/0, when a single 4/0 would make for less connections?

 

[sunshine_eggo]

Please excuse my stupidity, but why can I use 2/0 between the batteries and 4/0 between the battery buss bar and Multiplus? Whouldn't they be carrying the same load?

since they're in parallel, the 2/0 will carry about 1/2 the load.

Why does victron recommend 2x 1/0, when a single 4/0 would make for less connections?

Victron has two terminals per pole. Have you seen how thick 4/0 is? I know I recommended it, but I'm not certain you could feed 4/0 out the slot.

 

[RoadTurtle]

since they're in parallel, the 2/0 will carry about 1/2 the load.



Victron has two terminals per pole. Have you seen how thick 4/0 is? I know I recommended it, but I'm not certain you could feed 4/0 out the slot.

On just the battery interconnect, still struggling with understanding why they can be 2/0, while needing 4/0 going to Victron?

 

[sunshine_eggo]

On just the battery interconnect, still struggling with understanding why they can be 2/0, while needing 4/0 going to Victron?

Clear?

 

[RoadTurtle]

Clear?

Very much so, thank you!