My battery will be going into my hatch so I want to ass a fuse on the 4 guage lead power wire, my car is just a 94 escort. This fuse will only be for the charging/starting system. My wires for my amp have there own leads.
You will be able to put a 100 amp fuse on the charging side ,
( 90 amp Alt ) but the starting side is capable of drawing
400+ amps . No one I know of makes a reliable fuse that is
rated for that many amps @ 14.5v . I have seen people use
bar type AC fuses , but they are large and usually rated @ 220v .
so they react too slowly in a low voltage circuit .
Your other option is to split out the starter circuit at the battery and use
a starter solenoid close to the battery . This way the starter circuit
is open ( Dead ) when it's not in use .
It isn't complex wiring , but it needs to be done correctly because
of the amperage involved . That means quality connections and
carefully routed and protected cabling . If your not 100% confident
in your ability , then have it done professionally .
Do you have a diagram on how to isolate the starter circuit?
I have seen 300 amp ANL fuses that are used for steroes, I guess those will work.
EDIT: Found some 500 amp ANL fuses