Aftermarket electrical systems Aftermarket electronics only! stereo head units, CD players, MP3 players, speaker systems, amplifiers, hardmounted GPS devices, computers, headlight upgrades, fog lights, off-road lights, general wiring and anti-theft devices.

Big Three Upgrade

Old 12-18-2017, 02:52 PM
Junior Member
Thread Starter
NEcherokee's Avatar
Join Date: Apr 2017
Posts: 40
Model: Cherokee
Default Big Three Upgrade

For those of you who dont know this upgrade replaces or augments three key cables in the electrical system with 1/0 or 4 gauge wires: the battery ground to chassis wire, the chassis to engine block wire, and the alternator plus to battery plus wire. This increases your electrical system's current flow capability, ensuring a more consistent voltage under varying demand conditions.

I am going to be installing a 500 watt amp for a 12"sub soon and I was wondering if anybody's done this upgrade to their Jeep. I also run a cb radio which draws power from the electrical system as well. If you have done this did it help with dimming headlights? or did they even dim at all when you installed a sub-woofer?

Another note/edit: I've been doing a bit more research and have came across the fact that my amp can push up to 650 watts if installed well, i know its better to have a slightly over powered amp but would running 650 watts rms through a sub-woofer designed for 400 watts rms be okay as long as i tuned it and set the gain well?

Last edited by NEcherokee; 12-18-2017 at 03:07 PM. Reason: adding another question
NEcherokee is offline  
Old 12-18-2017, 09:54 PM
CF Veteran
investinwaffles's Avatar
Join Date: Oct 2013
Location: Tarpon Springs, FL / Denver, CO
Posts: 2,085
Year: '98
Engine: 4.0 I6

I did my big 3 upgrade years ago when I had an Alpine type-R @ 1000w RMS. I was planning on adding another so I used all oversized 0/1 gauge and built my own wires using KnuKonceptz wire and a hydraulic crimper. I'm also running a Grand Cherokee 136 amp alternator, rewound to ~160 amps by a local alternator shop which is a great budget upgrade to the factory 90 amp alternator I had. makes custom high quality cables for our XJ's, 4 gauge wire would be more than enough even if you do want to add more electronics

The important thing to note is the factory fusible link (positive alternator to battery wire) needs to be replaced with a fuse (I use AMG MEGA fuses). Additionally to the big 3, you will want to upgrade your battery to fuse box positive wire and consider installing a headlight relay as well for overall efficiency.
investinwaffles is offline  
Old 12-19-2017, 10:52 AM
Junior Member
Thread Starter
NEcherokee's Avatar
Join Date: Apr 2017
Posts: 40
Model: Cherokee

Awesome info thank you very much, you just explained almost exactly what I was looking for. Im going to do the big three upgrade and do my headlight harnesses as well. If i ever decide to add a second sub-woofer and another 500 watts ill probably go to a Grand Cherokee alternator for that extra boost.
NEcherokee is offline  
Old 09-27-2018, 12:32 PM
blprice's Avatar
Join Date: Nov 2017
Location: Columbia, Maryland
Posts: 3
Year: 2002
Model: Grand Cherokee(WJ)
Engine: 4.0 6 cyl

Hey NEcherokee, I upgraded mine months ago. A forum member Neal Emmons made mine. Great guy to deal with, does GREAT work and the wires are really heavy duty. I also replaced my alternator to a high output alternator just to be safe.
All new speakers (Kicker), fronts with crossover, rear & double 12" bass in the back cargo area. This system, makes the factory system, sound like music coming from a swimming pool (under water), 100% improvement over the factory system.
blprice is offline  
Related Topics
Thread Starter
Last Post
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
10-20-2013 09:29 PM
Modified XJ Cherokee Tech
09-23-2013 04:11 PM
Off-Topic Discussion
06-12-2012 05:24 PM
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
04-06-2011 07:59 PM
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
07-02-2010 09:33 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools
Search this Thread
Quick Reply: Big Three Upgrade

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.
  • Ask a Question
    Get answers from community experts
Question Title:
Your question will be posted in: