Let me give the correct answer for this one:

1. JL recommends 4awg power wire for their amps. 8awg is not a great idea for a 500/1.

2. 4awg is recommended for use up to 150 amps (A). Wattage is irrelevant since some amplifiers are more efficient than others, thereby making more wattage with less amperes.

3. JL 500/1 requires a 50A fuse, as does the 300/4 if I remember correctly, meaning you could run three JL amps such as these on one run of 4awg.

Don't get me wrong, if you're looking to expand in the future past 3 of these amps, then more is always better, but don't spend your money on huge wire if you are not going to need it. I installed 1/0 awg in my cougar but realized later that 4awg would have been just fine. (500/1, 300/2, and 300/4)

You should probably run the 4awg into your trunk, then a 4awg to 4awg distro block, and 4awg to each amp. If you had both amps playing sine waves and managed to pop the fuses on both the amps simultaneously, you would in theory only be at 66% capacity with your wire. Not likely to happen.

@caelric: why did you run 1/0awg ground to your trunk? ... upgraded battery cables and a split-up grounding location would do the same/better... and not to mention cost a hella lot less... or maybe a battery in the spare tire well...

 

Already upgraded the "big three" as well as a engine grounding kit (not sure the engine grounding kit makes much of a difference, but it's pretty...

As for the grounding point versus running cable back to the battery: I was getting some minor ground loop problems, because I had various things grounded to various places (amp and carPC in trunk, carPC screen and head unit up front, UTEC in another place, etc...) With everything grounded to the distro block in the trunk, and that distro block running back to the battery, I completely got rid of all ground loop noise, and I also ensured that I had a good solid ground for anything I need in the future.

 

My owner's manual for my 300/4 and 500/1 both say 8awg is ok to use.

 

Who recommends 4awg for 150A? CEMA recommends 4awg to be used with up to 125A for runs less than 10ft. Anything over this you should use 2awg or 0awg (more common).

Fuses don't blow at their rated current. They will handle:
110% - 4hrs
135% - 1hr
200% - 5min

The main fuse is NOT to protect the amps. It is to protect the car. If you were to have a 150A fuse on a 4awg wire and get in an accident or short the power wire is some other way, it would need to handle up to 300A for 5min without melting and/or burning up. This would NOT be a good situation.


JL recommends 2awg or 0awg be used for the main power wire with a distro into 4awg.


From my experience (and I have a lot ) you are right at the edge. You may get away with running 4awg back and splitting into 2 8awg but you will most likely have more than a 0.5 volt drop on the wire. This will make your amps work harder and COULD give you problems. If you listen to your music at high volumes, I would run at least 2awg distro to 4awg.
I personally ran 0awg to 4awg and added an extra battery.

 

You are pretty much right, you could go either way. I'm mostly just being cynical, most of the people at audio shops who "know for sure" what gauge of wire to run don't base it on numbers but on what they think would seem coolest. I believe my 150A rating was a Stinger statistic, but such recommendations are bound to vary, and 125A is probably safer anyway. Shops around here actually don't sell 2awg (2 x 4awg) but they do sell 1/0awg (3 x 4awg)...

If I insinuated that the 150A main fuse is to protect the amps, that was not what I meant, the battery fuse is to protect the garden hose running through your vehicle from turning into a lava rope. Flaming 1/0awg under your seat is a BAD THING.

Adding an extra batt is a great idea but there isn't much space for it in a G unless you don't actually put things in the trunk (I do.)...

I actually use a circuit breaker and a fused distro block, so I'm not sure if circuit breakers pop as slowly as fuses would. I'm not sure that the generalization about current percentages and time-to-fail is 100% correct, I know for a fact that I've popped a fuse in that vehicle with two JL amps, and there was no way I was running that much current (300A?) for that much time (not even a minute)...
Regardless, there is some wiggle room in fuse ratings, and it's best to be safe.

 

Yeah, it will tell you that... but when your 500/1 shuts off during hard use, that will be the reason why.

Happens all the time, to me, to other people, 8awg doesn't keep enough voltage to get the job done unless you're running a cap... which is silly on 8awg wire.

 

So far that hasn't happened but it's probably because I'm only running 1 10w6. I guess I might start having problems after I add the second.