Circuit Breaker on Ammeter Bypass
I'm doing the typical ammeter bypass using a fat 8 gauge wire from alternator to starter relay (overkill?).
This sentence is confusing. The ammeter bypass really has nothing to do with the way the alternator feeds back to the battery. The ONLY thing the ammeter bypass does is eliminates the ammeter gauge which is the weak link in the OE electrical system.
The ammeter in our cars was a left over item from the generator days when there was less overall current passing through the system. For whatever reason (probably $$) Chrysler never updated to a voltmeter so we are stuck with the antiquated ammeter. The reason the gauge becomes the weak link is because ALL the current that goes through the car passes through the ammeter terminals. So, if there is a short or high resistance somewhere in the system, the excess current created from these situations will pass through the ammeter. The gauge was in fact designed to monitor the system based on overall current but in reality, the gauge itself and wiring is not robust enough to handle too much extra juice going through it and can end up melting and causing a lot of collateral damage.
The weak link idea becomes especially true over time as wires get old and are more susceptible to high resistance and shorts. The bulkhead connector is a major culprit of this particular situation.
I want to use a circuit breaker as opposed to a fusible link, so I don't have to worry about having a spare. Is this a good idea? What is safe amperage for 8 ga? I'm thinking of something like this:
http://www.summitracing.com/parts/bss-cb185-50/overview/
I don't think a circuit breaker is a good idea because for one, it can reset. A circuit breaker also has the potential of not working until it's too late, depending on what its rated for. If you melt a fusible link, the system is disconnected from power. In any event whichever circuit protection device you use really only comes into play if you have a big enough problem that is causing excess current to go unchecked through the system.
What is the rest of your electrical system like? Is it in good shape or is it trashed? Is your junk blowing fuses or are you experiencing any bad wiring problems? If you have accessories that draw a lot of amps, think about using relays to shift the load. Your wiring and associated components are old. This stuff was not really designed to handle high output electrical loads unless modified accordingly.
I basically rewired my entire car last year but left some of the OE stuff if it was serviceable. I did the ammeter bypass. I also removed the bulkhead connector, cleaned it out and put everything back together using a lot of new terminals and packed it with dielectric grease. I have a circuit breaker on my car but it's for an auxiliary fuse box that protects stuff like a digital shift light and a tach sender. Not a lot of juice goes through it continuously. The rest of my stuff uses fusible links, solenoids, relays, switches etc. I don't really have any accessories so I don't use a lot of amperage, your situation may be different. I have a Denso 60 amp alternator and my battery is in the trunk with a cut off switch. Everything works good.
Sorry for the long reply, just needed a break from doing something tedious. Hope it helped.