wiring up a 2nd battery

I figured it'd be easier to just post a diagram as opposed to trying to explain what I am doing. Attached is the diagram of what I have figured out so far. Here are my questions. 1. Right now the alternator just hooks up directly into the factory battery, do I keep it this way? I am hoping so, as the second battery is located in the trunk. 2. Between the isolator and the two batteries I am using 1/0 AWG cable, I assume I should do the same for the positive lead off of the alternator. Am I correct? 3. Where actually do I need to fuse things? I've got a fused distribution block for the amps, and an additional fuse holder for the whole system, but I'm not sure where they go. THANKS!! Oh yea, the alternator is an Ohio Generator high current alternator.

You should put the fused distribusion block on the amp side of your deep cycle, and also another fuse on the positive of your main battery, before the isolator maybe just 6 to 8 inches from the positive terminal of the battery. As for the wire guage, it might not be necessary to use 0 guage off the alternator but it couldn't hurt.

always put the battery fuse 18" from the battery..

You need two fuses in the main power line between the front battery and the rear battery. Ideally, as close to the battery as possible but no more than 18" unless this is not possible. The first fuse should go between the main battery and the isolator. The second fuse goes near the rear battery. I would ideally like to see a third fuse and fourth fuse for you as well. The third is on the main power line right after the isolator on the way to the rear battery. The fourth fuse goes on the main power line from the alternator to the isolator. Put that fuse holder as close to the alternator as possible. Upgrade to 1/0 wire every place you can. Do not remove the factory wiring, leave it there and leave it connected. The idea is to add more wire to carry more current. Upgrade all ground wires to 0 gauge as well. Read the stickies on the forum about the Big 3 and What is a proper ground (some Canadian guy wrote that one up).Top Secret, I can tell you but then my wife will kill me.

Hey thanks for all the responses. I guess the only question left to ask is what size fuses I should be using. My sub amplifier has a rating of 120 amps, and the amp for my front speakers has a rating of 90 amps. Also, as far as adding a fuse between the alternator and the front battery, I'm not exactly sure where to go about securing the fuse holder. Any suggestions?