Charging Systems
The 100A fuse on the old set up is to protect the wiring, not the alternator.
You can keep the current LR set up using your new parts in this fashion:
Being that you have upgraded from 100A to 225A, as you stated, you will need to upgrade the wire from the new alternator to handle the amps. Downloadable charts are found all over the internet too calculate amperage * distance = cable gauge
Subsequently, you will need to upgrade the fuse.
Finally, you can purchase proper ring terminals to handle the larger gauge wire whilst still being able to fit the alternator to the fuse block with a smaller ring.
I've completed a similar setup using terminals purchased from NAPA. I prefer using marine Bussmann manual reset w/test breakers within the engine bay. These are waterproof and very rugged. Google: Series 18X Hi-Amp Circuit Breaker
You had made a suggestion regarding connecting the alternator directly to the battery... This is the way it was performed prior to the advent of engine bay fuse blocks. There is no harm. Be sure to add the inline fuse/circuit breaker between the alternator and the battery as to protect the wire.
Lastly, you stated that you planned to use a dual-battery set-up with isolation. You will be able to save many headaches by going with a marine battery isolator and gauging the wire accordingly from that point, i.e. 200A to isolator with two, 1 ea., 100A supply lines to original LR set-up. Remember, the installation of fuses/circuit breakers, when dealing with high amperage, is usually within 6-12 in. of the supply side.
Good luck,
Last edited by joshua.mcguoirk; 10-19-2014 at 06:12 AM.
Reason: Errata
1990 RRC, 3.9L, AUTO "Willow Pond" (Sold)
1996 D1, 4.0L, AUTO "Lucas"
1999 RR, 4.0L, AUTO "Belle" (Sold)