Big 3 should be same gauge as amp supply wire.

 

You guys do know that the shorter the wire, the smaller it can be in ga. for a given capacity, right? If the 4 ga. is a much shorter length than the 1/0, it could be fine and not a bottle neck.

If a person has 20 ft. of 1/0 wired from the battery to the back of the vehicle for power, and he uses say a 12" piece of 4 ga. for the battery to frame ground, it's not going to be restrictive. No, I haven't googled or wikipedia'd the specifications for current flow that a certain ga. of wire can give per ft. or length but I do know short runs can be smaller ga.

 

Okay, just because I'm sure somebody might argue I looked up some numbers.

1200 watt amp, let's say that = 100 amps of draw at 12V. Real-world conditions are going to be different since voltage at the amp might be between 13-14V when the vehicle is on and max. current draw would only happen when the amp is run wide open.

Anyway, 20 ft. of 1/0 at 100 amps and 12V = 0.404 voltage drop. 1 ft. of 4 ga. at 100 amps and 12V = 0.051 voltage drop. As you can see, the voltage drop from the SHORT run of 4 ga. is substantially less than the long run of the larger wire.

Reference: American Wire Gauge table and AWG Electrical Current Load Limits

 

x2

Just look at the strip size of a 300A fuse, it's tiny but it's only 1/2in long.

 

Yeah don't worry bro 4ga will work fine for you. I have exactly the same, 1/0 battery to amps, and 4ga big 3. If you had it and no money to get better, and it works go with it. We can't be wasting money these days.
HTH
Nick

 

its not that i dont have the cash to get it. I just got a bunch of that 4ga sitting around. the longest piece of 4 ga is no longer than 24 inches. my main power for the amp is 14 feet.

 

Upon further testing i am very impressed at how much this setup puts out for just a "throw in". this is the first system ive put in this blazer, i have noticed that at the back hatch there is two vents, one on either side. what have you blazer owners done about this. it has to be plugged. it makes some pretty hilarious noises. i am also experiencing very little to no voltage drop, goes form 14v to 13.7 at full tilt while idling. subs is seeing 1200 watts rms @ 4ohms. im going to drop it today to 1ohm, should see just over 2k rms. any suggestions on those vents?

 

bump for the amp gain AC voltage issue......

 

Small gauge like AWG 4 is fine provided it's only short runs of a few feet, but for longer runs like to the trunk, I'd use higher gauge like 1/0.