Is my fuse positive side correct 4x12v parallel to 3000w inverter?

[Mousie]

Okay, so I have 4 x 12v 100ah Renogy smart arrived today and will be in parrallel. My inverter is 3000w Meanwell. Using 3/0 cable and total path of cable lengths is under 2 meters total path. My inverter will never really exceed 2200w with single devices only in caravan. I was originally told no fuse needed between batt and inverter as inverter has input (12 x 40amp) fusing. However on reading these forums, I believe I should have a mega fuse on positive side from batt bank to inverter for batt and cable safety. Could I use a 300a fuse which appears to be similar to cable rating for 3/0 (95mm is the metric cable) or use a 350a fuse here for more wiggle room. Any advice appreciated before I buy this part of the build.

 

[Mousie]

Update, I checked the specs of the cable and is has a current capability of 416amps in air and 221 in conduit. So from reading, this fuse is there to protect the wire itself, therefore I think I could safely put a 350a (lower than total output of the batts) but more than enough for the inverter. Would this be the ideal fuse size?

 

[mopat]

My inverter is 3000w Meanwell

Is your inverter Mean Well TS-3000-112 ? The 12 volt model?

If so, that inverter can draw (suck) 300 Amps from the battery with a 3000 Watt load.

3/0 (000) battery cables are rated at 200 Amps.

cable rating for 3/0 (95mm is the metric cable)

The diameter of the 000 gauge wire is 10.405 mm.

The TNTS-3000 Instruction Manual seems to specify 300 kcmill cables:

For your implementation a 300 amp breaker should be OK.

 

[John Frum]

@Mousie
3000 ac watts / .88 inverter efficiency / 10.5 volts low cutoff = 324.675324675 service amps
324.675324675 service amps / .8 fuse headroom = 405.844155844 fault amps

That means 4/0 awg pure copper wire with insulation rated for 105C and a 400 amp fuse.

A 3000 watt inverter at 12 volts nominal flirts with the impractical.

 

[Mousie]

Thankyou for this. The Meanwell is the 12v variety 240v and was gifted to me hence why it’s going in. The maths on fuse calculation is great as gives the understanding. The only part I found a tad difficult was the various cable current ratings from high quality suppliers. For example one major supplier in Aus sells pure copper 95mm sq with a manufacturer specs current rating of 295 amps and the supplier I used has a different branded 95mm sq with the higher 110 deg rating with way high amp rating in the manufacturer specs. End of day, will go with the lower fuse rating for now as in reality, the inverter will want to draw/ deliver more than the supply here.

 

[John Frum]

Thankyou for this. The Meanwell is the 12v variety and was gifted to me hence why it’s going in. The maths on fuse calculation is great as gives the understanding. The only part I found a tad difficult was the various cable current ratings. For example one major supplier in Aus sells pure copper 95mm sq with a manufacturer specs current rating of 295 amps and the supplier I used has the same different branded 95mm sq with 110 deg rating with way high amp rating in the manufacturer specs. End of day, will go with the lower fuse rating for now as in reality, the inverter will want to draw/ deliver more than the supply here.

If they are both 95mm2 pure copper it comes down to the insulation rating on the wire.

 

[John Frum]

It also comes down to the which regulatory domain you are trying to comply with.
Can't be arsed to fix the dangling participle.

 

[Mousie]

Thanks, that makes sense now on insulation rating. unfortunately in aus, there is little regulatory in Caravans on the 12v side.