5 or 6 feet of wire running to inv is short enough. You do not have to go crazy. 10 feet of big wire would work too, but keep it short if you can.
There should be a big wire running to your fuse box area (or circuit breaker). Connect there instead of to the battery if the feed wire is big wire. Battery terminal connections tend to corrode on the battery, so best practice is to connect one wire to battery, run that to a location to connect everything else. Batteries off-gas and that gas is corrosive and will make a mess, corrode, turn green and cause loss of contact. This is why other guy says to install in different compartment.
