Greatest Limit In System: Alternator or Battery?

[ModernDayHero07]

I think we all can agree that car audio, or anything to do with audio or electronics, can be the most frustrating things to discuss with other people due to the difficulty of understanding and conceptualizing electricity and electronics. In short, there are a lot of ignorant and arrogant people out there who claim a lot of bulls**t to be true yet there are also people who really do know what they are talking about. The trouble is going through all the trolling and blabbering to decipher who really is speaking the truth. To me, the best way to approach this is to first take a step back, and then look at the science, or math. I am a student majoring in Electrical Engineering and I do not know everything. I do though know enough to ask some questions. (Sorry for the monologue introduction. I am venting from the hours of scouring the internet for answers and only finding ignorant arrogant trolls.)

SOOOOO, my question for this topic:
What is the true electrical limit for a system?

I know that the alternator supplies most of the electrical power to the car, while the car is running. When the car is not running, the electrical power is coming from the battery.

So: If the car is running wouldn't the only electrical limit be the amount of amps that the alternator can produce?

I am asking because there are quite a few people who say just to upgrade the battery or add a battery. How would that help if the car is running?

For example:
I have a 2007 Ford Fusion. The battery is a Die Hard Gold. The stock alternator is 150 Amps. I am assuming that is peak amps at a high rpm (not sure specifically what rpm). I am also guessing and figured that the car's basic electronic needs (like the computer, fuel injector, and other important electrical components) will need about have of the alternator's rating, so about 75 amps which is about 1100W while the car is running (14.5V). Let me know if this sounds flat out wrong. I want to get 2 SA 8 v.2's and push them with an amp that can deliver 1500W RMS @ 1 Ohm (750W to each sub) safely, efficiently, and cleanly. Now, if the car's basic needs take up 75 Amps of the alternator and even if I could get all of the other 75 Amps from the alternator (which would be at its peak at a high rpm), I still wouldn't have enough power for to get to my amp to give to my subs. The ultimate best I could do is 550W to each sub and but is still in a perfect world of amplifiers with 100% efficiency. If I included a realistic 85% efficiency, each sub would only be getting about 460W.
So, the problem: I don't have enough power to supply my amp.
Solution: Get more power!
How do I get more power?
By increasing the power supply's power output.
What is the power supply?
BING BING BING BING BING!!!!! That is the $1,000,000 question of this topic!!!

So many people say just get a bigger or better or more batteries, which would work it the car is off. But for me, I am in my car to drive. When I am driving the car is running. When the car is running, most of the electricity is coming from the alternator. SO WHY DO THEY SAY TO USE BIGGER OR BETTER OR MORE BATTERIES?!?!? Do they only listen to their system with the car off? And even then, how could a stock alternator handle charging a battery bigger than it was designed to charge AND also power the essential functions of the car AND power the sound system?!?!!

If anyone is going to answer my questions, at least answer the last few. AND PLEASE!! Don't answer if you don't know. I don't want to become a false informed ignorant douche. I am not looking to pick fights, neither do I enjoy others fighting, so please: RESPECT EVERYONE'S POST and if you think they are wrong, then spend the time to KNOW they are wrong, otherwise, if you KNOW they are wrong, please RESPECTFULLY LET THEM KNOW WHAT THEY GOT WRONG AND CORRECT THEM and explain if necessary. Just because the other person is not in front of you in person doesn't mean you can insult them.

NOW, let's talk ELECTRICITY!!!!!!!!!!!
PS: This is my first post, so be please be extra nice...... if possible.

[john253a]

What was the question again?

[WastedTalent]

What's the greatest limit in a system... alt or batt? There ya go John Lol

[Emmet]

Well that was a little confusing to read. From what I take from it though is you think that batteries are not used when the car is running.

If the alternator can't supply enough current, the battery bank helps support the draw. It isn't batteries or alternator, they go hand in hand.

If I'm honest, I find it a little hard to believe you're majoring in electrical engineering.

Or else you just started.

[STEALTH808]

My advice to you is that you switch majors asap.

[Rockford96]

Huh? I didnt follow that.. but get a bigger alt..

Alt > batteries

[Tribe Called Bass]

Alternator generates the power, battery's help sustain the power. Lack of battery's beats up your alternator, lack of an alternator drains the shit out of your battery's. So to answer your question, they are both a huge limit. My battery/alt set up will be more than my amp and 2 12's put together, sadly. You need power in order to hear the power.

[inferno1985]

there is your answer ^

[ModernDayHero07]

Actually.... I just switched to Electrical Engineering from Mechanical Engineering this semester, but I am only taking one electrical class right now and it is only a small basic course for mechanical students to take. So, technically, I haven't started studying Electrical Engineering yet. So everything I have learned so far in this field has been from other people and the internet and like I said I am fed up with being misinformed and wanted to get it right and post here in the forum. But I see what you all are saying: both are equaling important when the car is running. And that brings me to my next question, how do I determine how big of an alternator I need and how big of a battery I need to support my audio system? To make it simpler, for my audio system I need a grand total of about 2300W. At 14.5V, I need about 157 Amps. My stock alternator is 150 Amps and I have a Die Hard Gold battery: what do I need to do to my power system to make it able to support those 157 Amps?

[ModernDayHero07]

I got my knowledge of alternators and batteries and their purposes from here: http://www.bcae1.com/charging.htm

Is bcae.com not a credible source? Do they not know what they are talking about? Because they clearly say "As long as the engine is running, all of the power for the accessories is delivered by the alternator. The battery is actually a load on the charging system. The only time that the battery would supply power with the engine running is when the current capacity of the alternator is exceeded or when engine is at a very low idle. "