Would it be good for running from the alternator? I am planning on installing my Hella 550s, along with the Hella floods, so I want to pre-wire it for a higher output alternator. The wire I have is Kicker Hyper flex Power Cable (it has a bunch of tiny strands to make it super flexible). I got the cable for free from a friend, and want to put it to good use. I have 2 5ft pieces of it (one blue casing and one gray casing)

 

I wouldn't source power for anything from the alternator output- it should all come from the battery. Might not make sense but that's how it should be. You want a central point for wiring accessories and such and the battery is a logical point to connect to.
Afterwards, upgrade the wiring from the alternator to the battery as required.

 

I am not running the lights from the alternator lead, but from the battery. I am planning a 2 battery system as I will be working at a ski resort this winter, so I need extra CCA's when it is 0 degrees F outside. The Hella 550s came with a relay to run from the battery, so I will just copy how I had them installed on my Suzuki Sidekick. I am just wondering if 8 gauge wiring is enough to handle the loads? If it isn't, I will source better wiring (I am trying to plan in advance for making it hold up to harsh climates, and demanding conditions). I am also planning on getting a higher output alternator.

 

If your are installing an 80 amp plus alternator I would run 6 gauge, even on a short run 8 may get warm on a heavy draw.

If you are asking about the wire to the lights, that all depends on how many lights and how long your run is. However 8 gauge should be enough to run 2-3 lights.

If you are asking if it enough to run between your 2 batteries then NO. Even a short run between two batteries should be at least 4 gauge, preferrably heavier. My dual battery is in the back of my 4Runner (16' run) and I used 2oht.

 

Im in the process of gathering parts for my MR2 100 amp alternator swap, and im upgrading the wire from the alternator from the stock 8 gauge to a much heavier 4 gauge, and im running the wire directly from the alternator to the battery and then from the battery to the fuse box, and then im removing the unused factory wiring. The 8 gauge wire you have probably won`t be heavy enough, thats just my opinion, and it may work just fine, but if you plan on doing an alternator upgrade the 8 gauge definatly won`t be heavy enough, i would recoment at least 4 gauge wire.