You can have virtually unlimited fuse panels and accessories connected, it just comes down to making sure your average constant load is less than the output of the alternator. Remember alternators don’t always put out their peak, and not all devices pull current at their rated load.
If you are running a lot of devices I would temporarily put a shunt inline so you can actually measure how much you are drawing...
And as always, make sure the wiring is up to the task and that it’s fused with a fuse capacity LOWER than the rating of the wiring. In the past I have grabbed mini distribution panels which I mount right next to the battery...
so it goes battery terminal to distribution fuse panel with 0 gauge wiring (I also personally run fused battery terminals). The distribution panel then has ~8 very large fuses (60-120amp) which then run to other fuse panels (the gauge of wiring is usually 2 gauge).
wiring up a vehicle isn’t difficult, just spend the money on quality wiring, get decent OEM fuel panels from late model vehicles from a wrecker and ideally spend the timing drawing up wiring diagrams (I use a program called tinycad, but I’m sure there are better programs out now).
finally, if you are running a lot of stuff I recommend getting a doner wiring loom from a late model NON-Canbus high spec car (~2000-2010 Range rover) is a good choice as it comes with a lot of long wires. That way the wire is relatively new, contains lots of unique colours which are very long. Combine this with a well draw wiring diagram you print, laminate and keep in the glove box and you shouldn’t have any issues.
cheers
