Should i get a new alternator?/which one?
 

Im thinking yes i just want some confirmation/advice on which one. My running a q1.1200 thats pushing 1300watts to a single hds312. I have the honda accord coupe exl 2015 w/ the premium audio system. The stock alt i believe is 135amps. I have no idea how much the car actually uses of it but my guess would be at least 70-100 with the stock audio system, power steering, AC, VCM, camera/sensor systems. Im thinking about upgrading my amp to a Honda Accord High Output Alternators . Do you guys think this is necessary or should i just get a capacitor?

Or should i just do a double alt install?

The complication with 9th Gen cars is the LIN BUS communication with the alt for regulated output. Quality Power has participated in the forum and understands the complexity of 9th Gen cars. It appears they only have the V6 version for 2015, you may want to contact them directly to discuss.

Are you seeing issues with massive voltage drop (other than the alt regulating to 12.5V when the lights are off?). I have YouTube videos of the voltage regulation behavior.

Anything under 2kW rated can be ran on the stock alt with a good battery. Music is dynamic, and actual power output is always much less than you expect due to box rise and impedance curves (meaning actual impedance seen by the amp is usually twice what you expect). Amps with fully regulated outputs (make power at any impedamce) such as RF BDCP or JL Slash, can deviate from this.

Describe what you are seeing for voltage drop, please.

I have the V6 Most songs will stay at 14.4 and only during the heavy bass go down to 13.x and rarely 12.x

you may notice that when engine RPM are low (i.e. idle) you see voltage drop. this is normal. a much larger alternator may alleviate that, but at the cost of less fuel economy (they are harder to turn when making more power).

if you stay around 14V i would just leave it as is.