How-To: Big 3 Upgrade (Extremely Pic-Heavy)

[mblouir]

Glad to do it! It was fun for me and hopefully it makes this easier for others.


Two things were brought to my attention:

1. Wire Loom
2. Fuse Rating

I will be putting wire loom on all the wires---I was just running short today and it's been a long week. I wanted to put this up while I had the spare time.

I used a 250A fuse because KnuKonceptz rates their flex cable at "over 300A". Some people say match the ratings, some say you don't need a fuse, etc, etc. First of all I used a fuse to be safe. Even though power flows both ways I don't want the wire to get overloaded. I chose a 250A fuse because in the case something happens I want the fuse to blow before the cable reaches its limits. Just staying safe.

The main purpose of that fuse isn't to protect the cable, it's to protect the alternator. You want the fuse to be just slightly above the rating of the alternator so that if something starts making excessive demands on it the fuse will blow before the alternator fries.

For a stock 100 amp alternator I'd use a 125 amp fuse. On my 140 amp system I use a 150 amp breaker.

I was always under the other assumption. No one's ever said that from the Big 3 upgrades I've read. Thanks for pointing that out, Bernie! Looks like I need to purchase a new fuse.

 

[stadt11]

^ I've heard the opposite too, on countless threads of Big 3 Upgrades, they always say to use the fuse rated for the cable.

 

[mblouir]

Just got a chance to read this.


Sucks I can't really use this though:





Good write up. Thanks for taking the time to use great detail and plenty of pics.

With a lot of people asking about this (or ones un aware of this upgrade) it's great it's a sticky.

nice write up!

Just saw your comments, guys. Thanks!

 

[Bernie]

^ I've heard the opposite too, on countless threads of Big 3 Upgrades, they always say to use the fuse rated for the cable.

For the lead between the alternator and the battery? Why fuse it to protect the cable, when the alternator will fry long before the amperage gets anywhere near the capacity of that cable? (1/0 battery cable is rated for 265 amps) Think about it... what does that protect? The alt will blow before the fuse will, which will then cutoff any current flowing in the cable. So you're using a $150+ alternator to protect a $7.00 fuse and a few bucks worth of cable.

 

[stadt11]

 

[mblouir]

Gonna go out tomorrow and take some new pictures. They won't be as in-depth as the first set that poofed on me, but they should help one out enough to get this done.

 

[Carolinaboy]

Yeah get on it!

 

[Shanks12]

Gonna go out tomorrow and take some new pictures. They won't be as in-depth as the first set that poofed on me, but they should help one out enough to get this done.

Thanks Matt!

I remember reading this when you first did this... and looking to do this in the near future!

looking forward to more pics!

 

[mblouir]

Here are the updated pics, guys. Hopefully they help. The pictures should be self-explanatory when it comes to cable locations, but let me know if you have any questions. I'll repeat what I said in the original post: this isn't a set-in-stone way....it's the way I did it.

 

[Carolinaboy]