alternator power wire?

[sirtokesalot]

today i traced the wire's from the alternator and found they ended at the fuse box. can i safely add a second wire from the alternator to the battery? reason for this is because i have a stereo in the car big amp and it wants more juice and i think im losing some power through those small wires leading to the fuse box first then to the battery.

[Fairtax4me]

You can but you need to put a fuse line line between the alternator and battery.

Look up the Big 3 Upgrade. Need to upgrade power AND ground to get the most out of your amps.

[Bushwick]

Don't bother running it to the battery. Instead, run your amp's 12v+ cable (better be fused) and connect it right at the alternator's charge post. I've done this on my cars for years now and it's worked better than running from the battery post. Another reason to run directly from alt charge post is you avoid having your car's electronics competing with your amplifier's 12v+. I had a Mark VIII with a custom wound alt that was bumped to 290 amp (from 130 amp stock) along with a custom ordered alt pulley to get it charging at idle, and had 120 amp being pulled from two Crossfire VR602's (60 amp each, legit 600 watt each) bridged to two 12's. Car was full power and had a compressor for air ride, etc. It never dimmed nor over overheated. Cable never got hot either. Some claim the battery acts as a buffer to spikes, but I've yet to see this be an issue and unless you want to run 1 gauge or larger, it's not worth having a big, power hungry amp competing through the extra cables.

 

 

Also, not sure which car you have, but unless it's an EZ36 Tribecca, your alt is probably under 100 amp. For whatever reason, Subaru ran fairly small amperage alternators with EJ22 and EJ25, and even 3.0L engine. I found this out when I got my 95' Legacy and discovered it had like an 65? amp alt or whatever and bearings were going bad and the only thing that had a 130 was the Tribecca. Good news is the Tribecca alternator fits an EJ series engine bracket. I had to grind some of the outer casing to clear the bracket as they added a stiffening support to the casting where the bolt goes through. I just notched it back until it cleared. ALL bolts are the same location. They also added an extra rib to the pulley. Surprisingly, if you install this alternator with the extra ribbed pulley, you can ignore the very outer ribbing facing the radiator-side and run your factory belt and it'll still line up 100%, and despite having one less ribbed belt, it won't slip though you have to go a little tight and run a good gripping belt like a Gatorback Good Year with cross sectioned pattern.

 

I've been running the Tribecca alternator on my EJ22 powered engine with the EJ22's factory serpentine (one less rib) belt for 2 years now and have a sub amplifier pulling 70 amp (two 12's and one 10 @ 2.67 ohm bridged- lots of current to do this) and a component amplifier pulling every bit of 40 amp (4 doors @ 2ohm stereo L/R with a mono'd channel @12 ohm off the bridged connection powering 4 tweeters and an MTX home stereo center channel with another tweet and two 6"). I only listen to classic rock and gains aren't crazy, but it gets played loud and am at the limit of the factory alt if night driving. Have a fused 12v+ amp cable's eyelet bolted directly to the alt's charging post and haven't any issues with fuse holder melting or cable hardening at the connector like I've seen battery connected cables do in the past when competing for current or worse melted fuse holders. I also switched to MAXI fuses and rubber holders because the plastic cylinder holders with glass fuses aren't the best for really high current draw. 

Edited November 17, 2015 by Bushwick