Announcement

Collapse
No announcement yet.

how much power do I need?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • how much power do I need?

    I am going to be purchasing a new alternator very soon
    my current alternator is only producing 90amps on a 2003 mitsubishi lancer. these are small cars and its hard to find alternators for them but I have managed to talk to a guy that said will do it for 400$ for a 200amp alternator that fits my exact car no modifications needed. I was wandering if 200amps would be too much. right now installed in the car I have 1 jbl 1200 watt amp and a fosgate 400watt amp and a 2 farad cap. my lights still dim. I bought another jbl 1200 watt amp to put 1 on each sub and will also be buying an optima yellow top. I was wandering is 200 amps is over-doing it for 3 amps. each jbl amp has 3 40amp fuses in them and the fosgate has 2 - 40amp fuses. Also I was reading something about a battery doing 75ah does that mean even though my alternator is producing 200amps / second that the optima yellow top can only deliver 75amp/second? Sorry if this is funny but im kind of newbish to this. Thanks for anyones help

  • #2
    Everything you need to know can be found by clicking below

    Choosing a High Output Alternator

    Check out my CARPC: Project Diamond Plate

    Quick Reference:
    CPU Electrical Specs
    Power Supply Calculator

    Video Connections for newbies
    Temperature Converter
    Voltage Calculator

    Comment


    • #3
      sorry that it is sort of hard for me to understand but I think I have it right. the battery I am wanting to get has 75 amp hours. (optima yellowtop). so I divide the 75 / 2 which gives me 37.5
      then I will mutliply my current alternator by 40% which gives me 36 amps
      now I add my 36 amps + the 37.5 which equals 73.5 amps. therefore if I was to have a 200amp alternator I would have 126.5amps for the stereo. Correct me if I am wrong please.
      Even though I read all the information there, it still doesnt help me tell how much my stereo will need to operate. The link you gave me says 100amps for average stereo loads. I dont know if mine is below / above average. I appreciate the quick reply, im not completely stupid, I just dont wanna spend 400$ if I can buy a 160amp alternator for 200$... know what I mean.

      Comment


      • #4
        Originally posted by zbone1 View Post
        I am going to be purchasing a new alternator very soon
        my current alternator is only producing 90amps on a 2003 mitsubishi lancer. these are small cars and its hard to find alternators for them but I have managed to talk to a guy that said will do it for 400$ for a 200amp alternator that fits my exact car no modifications needed. I was wandering if 200amps would be too much. right now installed in the car I have 1 jbl 1200 watt amp and a fosgate 400watt amp and a 2 farad cap. my lights still dim. I bought another jbl 1200 watt amp to put 1 on each sub and will also be buying an optima yellow top. I was wandering is 200 amps is over-doing it for 3 amps. each jbl amp has 3 40amp fuses in them and the fosgate has 2 - 40amp fuses. Also I was reading something about a battery doing 75ah does that mean even though my alternator is producing 200amps / second that the optima yellow top can only deliver 75amp/second? Sorry if this is funny but im kind of newbish to this. Thanks for anyones help
        OK, here's the equation we need in order to calculate how much amperage you need at the alternator:

        Average Current Required to Supply Non-Stock Loads (A)
        +


        50% of Total Battery Bank Capacity (B)
        (in Amp-Hours -- NOT cold cranking amps)
        +


        Maximum Vehicle Electrical Load (C)
        (for vehicles, typically, 40% of max stock alternator output amps.)


        =
        Min. Alternator Continuous Duty Output Amps (D)
        (At your planned operating speed)


        We need to figure out the values above for: (A) +(B) + (C)= (D)
        Since you're not online, I'll try to do this on my own...


        (A) Average Current Required to Supply Non-Stock Loads

        Let's see, this is what I have for your fused rating on all three of your amplifiers:

        Fosgate= 80a
        JBL= 120a x2 = 240a

        so the combined total is:320amps

        To get your average we must divide the combined total (320) by three, that equals to 106 Amps


        We have the answer for A, lets move on to B:

        (B) 50% of Total Battery Bank Capacity

        And you said you want one Optima Yellow Top with a 75Amp Hour rating
        so 50% of 75 is 37.5 (B)

        (I suggest on getting three batteries to = 225 Amp Hours, But we'll continue the equation with your planned purchase)


        B is done, now Let's work on C

        (C) To calculate your Maximum Vehicle Electrical Load which is typically 40% of the max stock alternator output amps.

        I am assuming your stock alternator is an 85 amp denso unit, correct?

        If so, then 40% of 85 amps is equal to
        34 Amps (C)

        A(105) + B(37.5) + C(34) = D 176 AMPS


        Originally posted by zbone1 View Post
        sorry that it is sort of hard for me to understand but I think I have it right. the battery I am wanting to get has 75 amp hours. (optima yellowtop). so I divide the 75 / 2 which gives me 37.5
        then I will mutliply my current alternator by 40% which gives me 36 amps
        now I add my 36 amps + the 37.5 which equals 73.5 amps. therefore if I was to have a 200amp alternator I would have 126.5amps for the stereo. Correct me if I am wrong please.
        Even though I read all the information there, it still doesnt help me tell how much my stereo will need to operate. The link you gave me says 100amps for average stereo loads. I dont know if mine is below / above average. I appreciate the quick reply, im not completely stupid, I just dont wanna spend 400$ if I can buy a 160amp alternator for 200$... know what I mean.

        Yes, I hear you, your proposed plan will work fine with a 200 amp alternator with the Optima 75 Amp hour battery. Since you only require 176 amps you'll have a little head room to raise your volume a little past 30 percent while traveling.

        Now if you want to blast the music while the vehicle is not running. You might want to add two more 75AmpHour batteries, with a dash mounted voltage gauge, to be on the safe side.


        Check out my CARPC: Project Diamond Plate

        Quick Reference:
        CPU Electrical Specs
        Power Supply Calculator

        Video Connections for newbies
        Temperature Converter
        Voltage Calculator

        Comment


        • #5
          I probably wont ever run the stereo when the car isnt on. Thank you very much for helping me, I can see how it can get frustrating exspecially when there are lots of new people and newbies n the forum. Another thing I am wandering is why you took 320 amps and divided by 3 to get 106, is the reason you divided by 3 is because each amp would be at 30% on the gains? I figured each amp would probably be at around 80% on the gains...
          I reread and you divide by 3 to get the "average" so since I will be getting a 200 amp alternator and be using 176 amps, I would have around 24 extra amps to play with to get alittle above average? so maybe 50% gains on all amps

          Comment

          Working...
          X