Pretty much it, Just fuse after first battery and just before second battery, Try to keep ground wire 18 inches or less if you can and keep the same gauge as the power wire. Another thing to consider is they say mixing two types of batterys Wet cell/dry cell etc. Shortens the life of the stronger one.alright so getting a second battery in is as easy as running battery positive from first bat to second and grounding the second also?
The "Big 3" wiring is supplemental not replacement, with the exception of the new ground you install from the negative battery post to the chassis. So, simply supplement a much larger wire from alternator to battery. Fuse? Though not necessary, highly recommended, IMHO.another thing.. i was looking for the postive cable out of my altenator and i found one that looks to be like 10 or 12 guage wire its really small. is this it? i would have expected it to be bigger. it runs to the starter and then bigger wire maybe 8 guage runs into my fuse box and out to my trunk where my battery is. can i run another 0 guage wire directly off the altenator alnog with the small one thats there and just not go through the fuse box and straight to my amp? its gonna **** im gonna have to buy so much **** wire since my battery is in the trunk