I have a lifepo4 battery which has an internal fuse of 200A combined with an 200A JK BMS. i want to connect 2 multiplus 3000/48/35 in parallel. Is it allowed to connect them without extra (energy dissipating) fuses?
You cannot run a single wire to both Multiplus. You must run separate wires to each one. Therefore, each wire - and each Multiplus - needs it’s own fuse.
I can run multiple 35mm2 wires from the battery terminals parallel to the multiplus inverters. The cable can withstand the 200amp current or even more in case of a failure.
The 200amp/20kA fuse already dissipates 18 watts at 200 amp. Adding more will make the dissipation 36 watt at 200 amp.
But jou will NEVER have 200a on that wire, maybe 50.
It could be more like 100 amps. the Multiplus 2 3000/48 can deliver 5500 watt for a short period of time. A 35mm2 cable can handle that, but a 70mm2 will have less dissipation. Although in normal operation a 35mm2 cable would be fine up to 3000 watt. But I could also wire the system with 70mm2 instead.
The wiring isn’t the problem, but Victron recommends a 125 amp fuse for the Multiplus 2 3000/48 but they don’t demand it. So in certain circumstances an other fuse than recommended could be allowed, but I didn’t find any specification of this.