Especially since the alternator in our cars is specific to 2010-2012 Fusions and Milans with 2.5s, so it's not like an aftermarket upgrade for a Mazda6 will work.
So I just got a 250 amp alt for my 2012 se 2.5 is it gonna murder my charging system, I did the big 3 as well. But I’m running 1800rms so I needed a small upgrade but don’t wanna ruin my car either....any help would be appreciated!!the highest I could clamp power wise was about 1000 CLEAN watts off the stock alternator with a 4000w RMS Crescendo bc3500d, wired at 1 ohm,
I have since upgraded to a direct swap mechman 270 model, tested at 325 amps @1800 rpm and added 2 6,000 amp batteries and another 50 feet or so of 1/0 wire, now after box rise I clamp in the 3,000 watt area, clean power, with about 1/10 of a volt in voltage drop, which is nothing, so i am ready to add another 3500,
On your stock alt, I would suggest running a 1200- 1500w RMS amp, because after box rise you'll be lucky to get 1000-1200 watts out of it, and your car can support this,
I ran approx 1200 watts after rise for 4 years on the stock alternator and battery, never any issues, minor light dimming,