by Luc » Tue Mar 04, 2003 6:27 pm
You have to understand that the stock alternator is only good for just the car's electronics itself as it was built. The fuse for the alternator is 100-A, but since the stock one only puts out 80~85A, it always need some extra headroom for protection, even with the built-in regulator. When you add those gigantic amps with Class A/B circuitry, it will draw much current to supply the load. Sometimes even Class D amps with switching power supplies can take a heavy load, even if their efficiencies are above 80%. You can't wish that Toyota just slap on a bigger alternator since in their mind, there's no reason to upgrade since it's adequate for the norms. Even for an Optima, there's no way it can supply that much current. I personally don't look at the wattage, but rather at the current draw on the amps.
1998 S/C'd 1MZ-FE A/T