Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

how do you calculate what size alternator to run with extra power mongering accessories?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by _DeeVee8_, Aug 23, 2000.

  1. _DeeVee8_

    _DeeVee8_ 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    149
    Likes Received:
    0
    I've tweaked out my alternator belt tension enough and I still don't seem to have anough juice to power the Sub, the lights, the A/C, And everything else that I want to put on ---like very near future--an onboard Welding Station-- so what do I need for an alternator to supply power for all the goodies that need it(oh yeah, winch, trailer lights, under body lights....)
    How do you calculate what the minimum size should be--'cause one things for sure-- STOCK ain't cuttin it anymore!

    Where can I get the best deal on a higher amp alternator?
    Is there such a thing as too much alternator power? I mean I have only one battery as of now



    "You tried your best and you failed miserably.The lesson is, never try" [​IMG]
     
  2. CrazeeBush

    CrazeeBush 1/2 ton status

    Joined:
    Apr 17, 2000
    Posts:
    464
    Likes Received:
    0
    Location:
    Middle Tennessee
  3. sosamantx

    sosamantx 1/2 ton status

    Joined:
    Aug 14, 2000
    Posts:
    393
    Likes Received:
    0
    Location:
    somewhere in Texas
    I do agree that you can't have too big of an alternator (current output), just like you can't have to big of a battery (cranking wise). For some of the bigger alternators they just recommend that you change to a bigger guage wire coming out of the alternator to the battery. Check out these guys, I haven't bought anything yet, I am just keeping them in mind. Also, make sure that you have a good battery with plenty of cranking amps. http://performancedistributor.webjump.com/

    Steve Sosa a.k.a. "sosaman"
    http://sosaman.home.texas.net/carpics.html
     
  4. Wheels

    Wheels 1/2 ton status

    Joined:
    Aug 18, 2000
    Posts:
    638
    Likes Received:
    0
    Location:
    Native Floridian living in Oklahoma, USA
    To determine the size alternator needed, calculate the highest current draw of the system. You probably won't be using the lights, A/C, Sub, etc., while welding, so the welder would be the highest. If the system only gives you the wattage you can calculate the current using the P = I X E formula. (P = power in watts, I = current in amps, and E = voltage in volts). Example 12 volts X 20 amps = 240 watts. When the system is listed as watts, then divide 240 watts by 12 volts and this will give you the amperage reading = 20 amps. Operating an alternator at it's max capacity all the time will eventually cause it to overheat and let all the smoke out of the alternator. And, as with any electronics, when the smoke is let out of the system, it won't work anymore. Using a higher amp alternator will not hurt the system because the output is only equal to the load applied. Low load, low output lower operating temperature.
     
  5. NYC K5

    NYC K5 1/2 ton status

    Joined:
    Apr 3, 2000
    Posts:
    185
    Likes Received:
    0
    Location:
    Staten Island NY/da bronx
    best way to calculate how much power you need is go to your fuse panel and add up all the current devices you want to have on at once and get an alternator slightly larger than that, just remember the more power it puts out the more it needs from the motor and belt, and it costs more
     
  6. blazer72

    blazer72 1/2 ton status

    Joined:
    Apr 13, 2000
    Posts:
    939
    Likes Received:
    0
    Location:
    KCMO
    Use one of the new gm CS130 or CS180 alt. there cheaper than the aftermarket ones and bolt on with little or no fuss. there are even adapters for the wiring. The nice thing about the new ones that there regulator are not on or off like the older ones, they ramp up to the output that needed not to there full output.

    In other word if its day time and just the motors running they put out 15 to 20 amps. If its night time and all the lights are on they could be cranking out there limit and then some. The CS family start at 105 amps and go up to 185. The 185 is what is used in the Caddys and such.

    I understand the jeep thing I drive a BLAZER!!

    Ken
     
  7. istallion88k5

    istallion88k5 1/2 ton status

    Joined:
    Jun 20, 2000
    Posts:
    139
    Likes Received:
    0
    Location:
    Cincinnati, Oh
    Hmm, I have a 88 K5 with A/C, I have 1 Sony 404eqx and a PPI power 1400 amps with 2 12" subs and a Kenwood Excelon 815 hu. I have a 105 amp altenator with only one battery and really don't have any problems. Some times I get a little light dimming effect when I sit idle for a few minutes but I am going to just add a cap to my amps to solve that problem.

    If it aint a Chevy don't raise it up!
     
  8. blazer72

    blazer72 1/2 ton status

    Joined:
    Apr 13, 2000
    Posts:
    939
    Likes Received:
    0
    Location:
    KCMO
    The caps are used to solve the problem or bass hit's with big amps wont help your problem of dimming light at low rpm. Reminds me of my blazer way back when it had the stock 1972 alt that put out all of 36 amps on a good day. going to 1/4 or 1/8 inch smaller pully on you alt would fix you up or even 1/16 may do it. you dont have to go much faster, you could set the idail up 50 rpm at atime to see were it stops dimmimg at.

    I understand the jeep thing I drive a BLAZER!!

    Ken
     

Share This Page