Stereo & Electronics - What size power wire to run in an 850W amp?

I just picked up an Alpine MRV-F450: 850W unit. Is 8 guage wire enough or should I use 4 gauge for power. The amp will have a 50A fuse inline with it. Thanks

Do I need a capacitor to? If so what kind/type? (One Farad of capacitance per 1,000 watts of power with a minimum of one Farad) With this formual would 1F be enough?

4 gauge. No Cap, they do not help as much as getting a better battery, alternator, and larger main battery cable (aka. big 3).

You would've been fine with the 8gauge. But 4gauge is plenty and there's no need for a Cap at the point just like BMNICOLOSi stated.

the big 3 was done a while back

no you dont need a cap. unless you notice your voltage is low, but that doesnt usually happen unless you have big subs with a small or stock alternator. and yeah 8 guage wire is good for 850 watts.

4 gauge at a minimum will work, but 2 gauge would be better.

Total RMS - Distance - 4 feet - 8 feet - 12 feet - 16 feet - 20 feet
100 ....................... 10 gauge ......10 gauge 8 gauge 8 gauge 4 gauge
200 ....................... 10 gauge ...... 8 gauge 8 gauge 4 gauge 4 gauge
400 ........................ 8 gauge ...... 8 gauge 4 gauge 4 gauge 4 gauge
600 ........................ 8 gauge ...... 4 gauge 4 gauge 4 gauge 4 gauge
800 ........................ 4 gauge ...... 4 gauge 4 gauge 2 gauge 2 gauge
1000 ...................... 4 gauge ...... 4 gauge 2 gauge 2 gauge 2 gauge
1400 ....................... 4 gauge ...... 2 gauge 2 gauge 2 gauge 1/0 gauge

Total RMS - Distance - 4 feet - 8 feet - 12 feet - 16 feet - 20 feet
100 ....................... 10 gauge ......10 gauge 8 gauge 8 gauge 4 gauge
200 ....................... 10 gauge ...... 8 gauge 8 gauge 4 gauge 4 gauge
400 ........................ 8 gauge ...... 8 gauge 4 gauge 4 gauge 4 gauge
600 ........................ 8 gauge ...... 4 gauge 4 gauge 4 gauge 4 gauge
800 ........................ 4 gauge ...... 4 gauge 4 gauge 2 gauge 2 gauge
1000 ...................... 4 gauge ...... 4 gauge 2 gauge 2 gauge 2 gauge
1400 ....................... 4 gauge ...... 2 gauge 2 gauge 2 gauge 1/0 gauge

Ive got that chart hanging in my shop just so i can shop juist so i can show customers why i have to install their system with such big/expensive wiring.

no you dont need a cap. unless you notice your voltage is low, but that doesnt usually happen unless you have big subs with a small or stock alternator. and yeah 8 guage wire is good for 850 watts.

I disagree with this, when I had my JL W7 with a 500 watt amp the alternator could run it fine. However, once I added my capacitor (1 farad) I noticed an improvement in the subwoofers performance. I would also run something larger than 8 gauge I was using 0 gauge wiring. This guy ^^^ was starving his subwoofer even if it was preforming satisfactory he would have seen an improvement had he upgraded the power delivery to the amp.

Picture the way an amp draws power as an empty canister. Each time the sub draws it load it fills up slowly then once its full it send the power to the speaker. With a capacitor it fills up faster than sends the power to the sub quicker and more consistently.

Total RMS - Distance - 4 feet - 8 feet - 12 feet - 16 feet - 20 feet
100 ....................... 10 gauge ......10 gauge 8 gauge 8 gauge 4 gauge
200 ....................... 10 gauge ...... 8 gauge 8 gauge 4 gauge 4 gauge
400 ........................ 8 gauge ...... 8 gauge 4 gauge 4 gauge 4 gauge
600 ........................ 8 gauge ...... 4 gauge 4 gauge 4 gauge 4 gauge
800 ........................ 4 gauge ...... 4 gauge 4 gauge 2 gauge 2 gauge
1000 ...................... 4 gauge ...... 4 gauge 2 gauge 2 gauge 2 gauge
1400 ....................... 4 gauge ...... 2 gauge 2 gauge 2 gauge 1/0 gauge

That chart looks very familiar. :lol:

4ga is it were me