Big 3 upgrade and ground issue HELP

[YoungBonne12]

so i bought some 0 ga looking to do the big 3 and i had one wire that was perfect for the ground so i did that one first. i didnt replace the wire that was originally on the stock ground. when i replaced the wire with the 0 ga, my voltage dropped from 15.4 to 12.9. what could cause this? do i need to replace the little wire that was originally on the ground? or what. because i dont want to do all this wire work if it isnt going to help me at all. thanks guys!

[harofreak00]

That little wire is for the main body harness, it needs to be grounded.

[YoungBonne12]

Could that be the reason for my voltage issues?

[YoungBonne12]

it turns out i just had a really bad ground. i cleaned it up and that put if back up to 15.3V which seemed. when it comes to the battery wire thoughh, do i need to run a separate wire from the front fuse box to the alternator? i just dont understand what gains i would see if i only replaced the battery + to the fuse box when the wire from the alternator to the fuse box is only 6 or 8 ga.

[Bugsi]

I just don't understand what gains I would see if I only replaced the battery + to the fuse box when the wire from the alternator to the fuse box is only 6 or 8 ga.

A garden hose can easily deliver 1 gallon of water a minute. You can hook up a 24" water pipe to draw 1 gallon of water a minute, but there's really no benefit or sane reason to do so.
It would be better if you told us what gains you were hoping to get from this. I suspect it would be instructional for you to put an ammeter in series with the 6 or 8 gauge wires that go to the fuse block, and then turn on every electrical device you can think of in your car, and see what the actual maximum current load through your fuse box is, and compare that to the ampacity of an 8 gauge stranded copper wire. Unless you're hooking up something to your fuse box that draws a huge amount of current, I can't see any actual benefit to hooking up the fuse box with larger wires. New wires could be beneficial if your old cables are corroded or damaged, but otherwise I don't understand what benefit you're expecting to get.

[Alpine_jake]

When i did mine i left the small wire from the fuse box to the alt and just put an additional zero guage from the alt to my batteries. so i left all the stock wiring there.