I think @chrisski is on the right track with the 24V suggestion. But if not, consider stepping up to 4/0. 3000W @ 12V is nearly 300A, possibly slightly more if you factor in inefficiency or slightly lower voltage (3000W / 12V / 0.85 efficiency = 294A)Thanks. All good points. I wasn't aware of the breakers being audio CB's. I will look at a replacement to fuses.
I got the 3kw inverter, not because I will use 3kw, but I don't want to run it too hot. I figure I will stay around 2kw for my work, but when I need to plug in my. welder, 3kw will do the trick for short periods. The cables between the batteries and Inverter and charger are 1/0 and less than 16" but I am open to 3/0, though I think the 1/0 should do the trick.
Thanks so much for the input. Very much appreciated. I spent a great deal of time thinking about 12v or 24v and the feedback was 50/50. I chose to stay with 12v because most power I use will be DC and adding a DC-DC converter is just another device to fail. The reason for 3000w inverter is, for the most part, to run a TIG welder. With a standby current approaching 2a, it won't be left on when not in use. I don't mean to weld all day, so rest assured I'm not crazy. Instead of 4/0, I think multiple cables would be my choice.I think @chrisski is on the right track with the 24V suggestion. But if not, consider stepping up to 4/0. 3000W @ 12V is nearly 300A, possibly slightly more if you factor in inefficiency or slightly lower voltage (3000W / 12V / 0.85 efficiency = 294A)
For wire safety (ampacity), distance is not a factor as far as I am aware, distance matters for voltage drop.
Here is an ampacity chart that shows you max ampacity for different wire sizes and temperature ratings (at 85*F and 120*F)
A couple other points that jump out at me:
- As has been mentioned a fuse, such as a class T fuse, rated for protection of large battery banks or lithium battery banks is worth strongly considering.
- I believe your positive wiring is incorrect, nothing should come between the battery and the first shunt. Loads come after the first shunt, solar (or all chargers) come after the second shunt.
- Question: what is at the bottom left?
I did the same thing. The original wiring from the battery was 12 inches long and 6 AWG. The busbar from the new battery bank took about 5’ of wire, and I went with 2 AWG. That’s plenty big for the rigs DC usage, except for the leveling jacks which is over 50 amps, and its adequate for that with a 5% loss.The bottom left image is the original battery compartment on my rig. I am using it as another distribution point.