Hey guys, so i've got a 1999 Corolla that I swapped in a 4th Gen 3SGTE.
The electrical system is stock except for the following:
AEM 340LPH Fuel pump
Spal
30102029 for the radiator (Rated @ 14.5A)
Spal
30102029 for the AC Condensor (Rated @ 20A)
See specs below
https://www.a1electric.com/catalog/cat_spal.htm
I had a 2UZ Alternator on it from the Sequoia (150A) that I destroyed immediately at idle when I turned on the High beams, fogs, AC. The instant that the both fans went into high speed the alternator started whining and the voltage fell immediately to battery voltage.
So I decided to go for a High output alternator from Autotech. I went with a 240A high output version of the 2UZ alternator(14.2V Setpoint). Now here's what I notice, whenever I start the car the alternator outputs 14.4 - 14.5V, great! However it gradually decreases over time until it settles at about 13.6V and it stays there. If the radiator fan turns on at high spee it pretty much stays outputting about 13.6V-13.7V, with the highbeams on it'll go up to about 13.8V. If I turn on he AC and let the fans cycle enough till they both enter high speed (where they both run at their rated currents) I see 14V. Also note that my ECU does not control my alternator, it's the typical Denso 3 pin regulator (S IG L)
Is this normal?
This is my first high output alt. My theory is that on startup, the battery is drained alot so the regulator ramps up the voltage as the battery at this point is a large load on the system, when the battery tops back off the voltage decreases as the alternator isnt really driving much of a load again. Same for the fan situation, when two of them are at full speed it puts a little load on the alt so it has to compensate. So i'm guessing in general my car doesnt put much of a load on the alternator so it mainly sits at 13.6V when the fans aren't running etc.
The reason why i'm concerned is because I was going to relocate my battery to the trunk and upgrade it same time. I wanted to get an Odyssey PC1200. Now Odyssey says that these batteries should see 14-14.4V to ensure long life and to prevent premature failure. Now this is a concern for me as you can see as my alt doesn't really output that unless I load it up. So would I do damage to an AGM battery if my voltage sits where its at? Or do they mean charging voltage? In which case i'd be fine as the alt safely does that at startup.
Also anyone has experience with the PC1200, especially for a daily driver?
