Ideas for wiring

[Leep]

I have here a 400 watt system similarly modeled after Will's 400 watt system. The issue I'm having is the positive wire (2awg) from the cutoff switch to the fuse (250A) get very warm when hitting near the limit of the inverter. I know that something needs to change here in terms of the layout, or the wire/switch/fuse. Suggestions on setting this up properly?

 

[RickP]

From the photo, it appears that there are several cables of that same size in the system. If there is only one cable heating up, I would be looking to heat causing possibilities in that section... loose threaded connection or poor contact, bad crimps, faulty switches. If you have a laser temp gun it will be easy to find the hottest/problem spot.

 

[Leep]

From the photo, it appears that there are several cables of that same size in the system. If there is only one cable heating up, I would be looking to heat causing possibilities in that section... loose threaded connection or poor contact, bad crimps, faulty switches. If you have a laser temp gun it will be easy to find the hottest/problem spot.

Everything is tightened snug. It heats up between the cutoff switch right after the battery and through the entire fuse system. I am open to hearing ideas related to how I could re-structure the 250A fuse system. Right now it's just a bunch of positive wires coming off one side.

 

[Hedges]

2 awg, 90 degree C wire, is good for 190 amps in free air. (30C ambient, 60C rise to 90C)
1200W inverter on 12V draws 100A, so just over half that temperature rise expected. (15 degree rise, could be 45C)

Measure voltage drop across switch, across fuse.
If any of those are notably hot, you could bypass it with a direct connection (carefully!) and see if it runs cool.

If that's a 250A fuse, wouldn't expect it to get too hot at 100A. But people do mention heat for some fuses like that.
If fuse is what's getting hot, class-T should be better.