'98 SC400.

I just ordered an amp (Alpine MRV-V500) that requires 4 ga power and ground wiring. My old amp wiring is 10 ga, so I'll have to order new stuff. The KnuKonceptz KCA-K4 kit is the obvious choice, with enough length to run from the battery up front to the amp mounting location in the trunk.

However, at some point I'll probably do a battery relocation to the trunk, for improved weight distribution. I need to get a sealed battery before going that route, so it isn't an immediate thing in the works. But, it would be silly to run the amp wiring now and then run battery wiring later, at which point the amp would be better off wired straight to the battery in the trunk.

So, is there any reason not to just run battery relocation wiring now and power the amp from that? I imagine a distribution block of some sort in the trunk would be desired to step down from battery (0/1?) to amp (4) gauge. I would run a bit more battery cable than needed, for future routing flexibility.

 

The related questions would be, if going with a distribution block like that, is it better to use a fused block or an in-line fuse, and if a fused block, what amperage?

From what I've read, the fused block would be safer because of the step-down in wire size, as the smaller 4 ga wire needs protection from the current the big 1/0 wire can carry. (I'll have to look back at my battery relocation notes. It may be that a fused distro block is best up front once I move the battery, so grabbing something now for the amp that can be used later for that purpose would be useful.) The amplifier calls for a 60A fuse, but I think 100A is more in line with what the distro block would need to handle?

Edit: Actually, re-reading one of the threads, the recommendation applied to my setup would be a 60A fuse in the distro block to match what the amp calls for, staying below what I gather is the 100A limit of 4 ga wire. The lower 60A limit protects the smaller wire just the same.

 

This probably answers my unasked question about the overall amperage capacity of a battery relocation, not just of the distro block to the amplifier:

http://www.offroaders.com/tech/12-vo...gauge-amps.htm

That scale tops out at 200A, which would make some sense because that exceeds most if not all alternators. 2 ga welding cable has been frequently recommended for battery relocation, and that chart supports it, as a 15' run at 200A would only require 4 ga.

 

I made a list of all the items I would need for the future battery relocation and current amp setup with as much of the first group already in place as possible, then talked myself out of it while putting together the order. At around $160 (cables, vented box, circuit breaker, distribution blocks, cable lugs, etc.), it makes more sense to just wait for higher capacity lithium batteries to go mainstream. I tried a smaller one for awhile and it did well enough, but lacked the juice to sit for a week with all the parasitic draws. That takes most of the weight off the nose, but it doesn't add it to the tail for as much weight distribution improvement.

So, I'll just wire up the amp as normal when the 4 ga kit arrives.