kejtar

So doing research in wanting to take better advantage of the alternator output I came across the big 3 (4) upgrade. The idea is to run new (additional) cables in the following places

- alternator to battery +
- alternator bracket to battery -
- alternator bracket to body
- battery - to body

I am planning to use 4 gauge to get better advantage of alternator output as the factory 8 gauge (it looks like 8 gauge at least).

I picked up also a 120 amp circuit breaker (my local electronics guy swore that this is the next best thing to sliced bread) to make sure that the 5 foot run doesn't go too far.

Any pitfalls in this? Anyone done something similar and is happy with the result?

augichef

I did my BIG 3 in 0 gauge..
Battery - to the frame
Battery - to the engine block
Battery + to the Alternator +
My fuse on the alternator is 250amp because I have a 250 amp high output alternator..

I can definitely see a difference in doing the big 3

Good Luck
Augi🍺🍺

kejtar

So you didnt do the engine block or the alternator frame to body?

karls10jk

Wire isn't cheap, particularly the oxygen free copper. What benefits am I going to see in doing this to my daily driver? I've converted most things to led and I have a weak audio system with no plans to upgrade.

kejtar

So in theory (since I haven't done this yet) you have a 168 amp alternator. You have most likely 8 gauge wire supplying the battery resulting in less power being drawn then you can from the alternator. The additional wire will allow you to tap into more of your alternator potential.

ronjenx

Upgrading the "big three" originally came about to fix the click-no-start issues a lot of JKs were having. Seems like most of them were automatics.
I believe the wires added were engine to body, engine to transmission, and alternator mount bolt to battery negative. I don't recall the alternator output to battery positive wire being part of the upgrade, as the whole deal was to upgrade the ground connections.

If you upgrade the alternator to battery positive wire, you lose the protection of the fusible link in the OEM wire.

jedg

Where is the circuit breaker going?

kejtar

Hence the circuit breaker. It goes on the positive between the alternator and the battery.

kejtar

Interesting as I didn't come across this version when I did my google searches. I kept coming up with the upgrade in the way I described.

EHarris

Funny this post came up. Just ran a wire from the battery negative to the alternator bracket. I have no idea if this is correct. I am hoping that it fixes my no start issue. If this does not work and fix my no start I will have to replace my WCM. Transmission range sensor "passed" testing as I had them check it when they did the rear main seal. I say BS and they never actually checked it when they did the rear main seal but I'll never know for sure. Here are some pics. Hope this $8 fixes if. So annoying to drive a vehicle for 120k and never know if this is the time it doesn't start.