Location of main fuses?

[anguilla1980]

I have my battery in my trunk, an billet alternator capable of just over 300amps, several fans/EWP/AC/tons of electronics and a stereo system. Basically think a worst-case for power draw lol. I have a 4 post cut-off switch by the battery with the A terminals going from the battery to the alternator and starter, then the B terminals going to the main power distribution point.

I currently have a Bussman 250amp main fuse but I'm wondering if it's still appropriate: https://www.amazon.com/gp/product/B000PSRANM

I think also that I should have 1 for the A terminals AND the B terminals instead of just for the B terminals like I do now. Also, I have it placed between the battery and the cut-off switch.

What amp fuse would you recommened for each and should they be between the battery and cut-off switch, or just after the cut-off switch?

I'm converting from the 12v system to 16v and thought I should address this in the process.

Thoughts?


Thanks!

[Richard454]

A couple of thoughts-

Why not use the cut-off on the negative terminal? No fuse needed- I realize some require pos side like NHRA- but the negative makes more sense on a street car.

A fuse's job-to protect the wire- you rate the fuse for the size of the wire's current capacities. You want the fuse to blow before the wire melts.

AND- the battery -if it shorts - the current keeps on going and going. The alternator shorts- a puff of smoke and it produces no more current.

There are several article out there talking about "dirty" current- and how the electronics like to be powered by the battery- as it not only starts the car- but stabilizes the voltage and acts as a filter to the AC ripple not cleaned up by the alternator.

I like how BMW does the wiring (and many new cars )- uses basically sub panels so to speak to distribute power to the locations you need it. I have done the same in my car's electrical layout.

Notice how the high draw dirty stuff ( starter /alternator) are on one leg separately fused from the rest of the system.

180823

Oh- these are the fuses I like-

Marine Grade- Blue Sea

https://www.bluesea.com/products/category/16/Fuse_Blocks?Fuse_Type=Terminal

180821

Fuse size- wire gauge

180822

[anguilla1980]

Where should I put the fuses? Before or after the battery disconnect?

[Richard454]

Where should I put the fuses? Before or after the battery disconnect?

As close to the battery as possible-for the main battery fuse.

And any time down stream when you change to a smaller gauge wire should be another fuse.

[anguilla1980]

As close to the battery as possible-for the main battery fuse.

And any time down stream when you change to a smaller gauge wire should be another fuse.

Thanks!