I would use one fuse between Bat and Alt:

Location: As close to the Bat as possible.

Fuse rating: The maximum the wire can handle (which had better be much higher than the alt's capability).

Grounds: In the case of a car accident. Jagged metal from an impact can easily cut that line and create a short circuit and fire. This is the only reason I would fuse that line.

 

Yes, but having one fuse is pointless, because it is not only robbing amperage, but serves no purpose. You need 2 or none.

 

I get the robbing amperage thing - fuses naturally add resistance which impedes electrical flow.

But you are going to need to explain why more than 1 is necessary. In the case of an accident, the alt (with the rest of the engine) will have stopped producing power, so the alt side of the wire is not the one dangerous for starting electrical fires. The battery, will be live until it is drained, leaving it dangerous - so I still stand on one fuse, right at the battery.

 

^ whats your theory for pointless?

a proper fuse that could protect the alternator will be way too small for the wire (if you have done the Big 3). most decent alternator puts out like "110Amps-140amps" cold with engine running vs most batteries has a cold cranking of "800amps-1000amps" constant. I don't quite understand what the second fuse is going to protect?

 

The second fuse protects your alternator from any power spikes.

 

what size fuse would you say would protect an 110amp alternator? and what are the "power spikes" from normally? (other then battery being jumped)

 

wow that just made me fell 100% smarter

and please tell me how that works

 

They aren't normal, its just in the event of. Could probably happen in an accident...

Dukk knows a lot more about the second fuse thing than me, hopefully he will make a post.

 

well then on another note would installing more then one chasis to battery wires help with flow even more or is that just pointless?