Fuse sizing (again)


New Member
Feb 11, 2021
Your fuse should be sized to protect the cable you are using (i.e. not above the rating for the wire/cable), then if lower, for the device.

The fuse is to prevent your wire from overheating and starting a fire. Individual loads should have fuses appropriate for their wire.
You can of course use smaller fuses, but never put a fuse on that is larger than what your wire can carry.
Yep, will be using 4/0 from inverter to bus bar and 4/0 from battery to bus bar, fusing down to 250, to prevent the bms from kicking in.


Apr 3, 2021
If you have sized a fuse for 350 amps, you really need to consider going to a higher voltage system. Start looking at the amps city of wire, When I checked, 4/0 goes to 260 amps. THat’s pretty thick wire to work with.

I am not a fan of 3000 watt inverters on 12 volt systems Because of how thick the wire needs to be, FOr systems that really gets used, 12 volts is good to 1000 watts, except for a four or five excursions a day to 2000 watts to power a microwave a couple minutes at a time. Many will disagree with that.
Picking your brain for a second, 16s 310ah bank feeding a 48v 3.5k hybrid. If the most I can run is 3500w, 30a ac, or 82a dc, what size fuse would you say for my main line fuses. Using #4 wire for the 2' run.
Appreciate it thanks.