- 3000w 12v inverter
- Battery Bank to Inverter - 4/0 AWG & 250a breaker?
I believe you'll need a 300A fuse. If you're using a Victron MultiPlus II, I think Victron recommends a 400A fuse.
3000W / 12V minimum battery / 90% efficiency = 278A mean current
278A x 1.25 headroom = 347A fuse normally recommended
347A x 1.12 ripple factor = 389A fuse my recommendation -->
400A fuse
Maybe 500 MCM 90 degree wire for 400A?
Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.
www.cerrowire.com
The 1.25x factor is to avoid nuisance blowing, including hot environment and heating from cables.
The 1.12x factor I recommend is because battery current is not steady, will look like a rectified sine wave. Fuse is heated by RMS current, not mean current.
After reading of someone tripping battery breakers at well below rating, I realized that could be due to pulses of current drawn by the inverter. Ideally capacitors would smooth out current draw so high frequency switching pulses and 60 Hz draw all came from the caps, and current from batteries...
diysolarforum.com
Although, 3000W continuous isn't very realistic for a 12V system.
Your battery is enough to deliver that for 3 hours, so things would heat up a fair amount.
600W of PV might deliver 450W, with 6 effective sun hours will take 4 days to charge batteries back up.
24V or 48V system would be more reasonable for your loads.
I am planning to put a 2500W MSW inverter on a pickup, but it is for occasional tool use, like pipe threader.