I upgraded the 60A alternator to a 110A one. The original charge wire was around 30A capacity with a 30A fuse.
I added a second charge wire with a 60A fuse. So, the combined ampacity of the two wires was roughly 90A(30+60).
The battery is generally at least 80% of it's state of charge, so the second 60A wire was not much of any use for a single battery most of the time, so I thought. 60A fuse of the second wire accidentally got blown & oddly enough, the alternator warning light on the dash came on. When I checked the wires and fuses, the old 30A fuse was still going, but getting pretty hot.
What was apparently happening was the Charge Acceptance Rate(CAR) of the battery was high enough to draw significant amount of amps from the alternator, and the old 30A wire and fuse was not quite enough.
My point being, that such an alternator upgrade does matter, even when a second auxiliary battery is not there to draw the extra possible amps from the alternator. The cranker for the most part is still capable of utilizing the advantage of the upgraded alternator, provided the charge wire and fuse are also upgraded accordingly.
http://www.nissanpatrol.com.au/forum...-short-circuit
http://www.nissanpatrol.com.au/forum...or-RB30-Patrol
So, the above rule of thumb,
("Rule of thumb for a standard Lead Acid vented battery at better than 50% charge is the CAR will be max 30% of the capacity IE 30 Amps
The limiting factor to current flow is the physics behind the battery
For the same battery at 80% the CAR will drop to around 15% of capacity.")
In my case, the battery is obviously on a far better charge state than 50%.
I would say 80% or more, yet it managed to draw way above 30A from the alternator, since the upgraded alternator was very much capable of outputting closer to at least 100A(for an alternator with a rating of 110A).
