no option for alternator above 60 amp

Discussion in 'Automotive Electrical' started by jgilk1, Feb 6, 2012.

  1. jgilk1

    jgilk1 Full Member

    ok so i have a 1976 chevy luv running a 1.8l motor the largest alternator that i can get (if there ever in stock) is an 60 amp alternator (or with a massive amount of modification an 80 amp alternator....

    currently i am running a 35 amp alternator with a full draw of 25 amp's with the high beams on (4 head lights), engine running, 35 watt head unit pushing 2 4" door speakers and the heater going full bore

    my plans involve upgrading the head lights with 4 90/100w head lights all 4 wired for high beam and low beam... so any which way yes a 60amp alternator will have no problem pushing these at full power (360w/400w or 25 amp) yeah i would be running ~80% duty cycle but that can be combatted with a spare battery and or some large capacitors

    the problem is when i upgrade the stereo to slim margins ie the head unit (100-150w 5 way) and throw in a 300w stereo amplifier and 10" pioneer low profile sub so another 450 watts or 31.25 amps

    so with the truck running at idle 14.4volts i will be pulling just @ 1420watts on the electrical system or 98 amps

    i will be contacting a few places here locally about the possibility of rewiring a stock alternator for 120+ amps but i doubt that any one will be able to pull 350% more power out of its small size 35amps vs 120amp we will see...

    but untill i get a response back from them i have a few questions....

    yes this in all reality is a small amount of load on an electrical system as most newer vehicles can pull 100 amps idling with everything off...

    ok so head lights are already fused both for high beam and low beam as is the headlight switch (yes i have 4 fuses for the head lights and 1 for the dimmer switch) so thats taken care of with this setup i believe the stock head light wires are 16-18awg running 55w high beams should i pull the wiring and replace it with something like 12-14awg?

    as for the main wires power to starter, power from alternator will end up all being upgraded to 4awg as well as replacement of all the grounds with stuff thats considerably larger (most are 8awg and they'll most likely end up 6awg)

    amp is going to be running 4' on 8awg power and long enough ground to mount it (less then 6") and sub speaker wires are 18awg monster audio

    does this sound suitable ? questions comments concerns go ahead and ask....
  2. pedro quiroga

    pedro quiroga Well-Known Member

    have you contacted any high output alt companies?

    or maybe have a custom alt bracket made and run a larger stock alt from another chevy?

    i have a friend that made an alt bracket for his 93 geo metro to run a chevy 105 amp alt and wired it(with resistors) to run 18v to power his 16v car audio set up. totally separate from his stock electrical. he has 4 16v batts in the rear to handle the stereo.
  3. 04nata

    04nata Member

    go to, they have one to fit all cars, thats where I am going for my 93 Hyundai Excel, 220amp (100@idle)
    Last edited: Feb 8, 2012
  4. jgilk1

    jgilk1 Full Member

    ok so for now i have purchased a newly used alternator out of a 1999 dodge ram 1500 its externally regulated (so direct wire in for electrical) and the brackets are only 1/4" differnet which can be adjusted for

    as for the posts above the chevy luv is a rebadged Isuzu nothing chevy other then shocks is interchangeable really

    so heres the setup when all the wiring comes in

    i will be running for now
    head unit, door speakers and sub box are temporary till funds are available there are a few things that are higher importance as of right now with the vehicle

    bosch 1974-01000486

    head unit
    2012 kenwood KDC-152

    door speakers
    (for now) scosche hd30004 (4" 3-way)
    (on temporary mounting plates) will end up using 5" components with 1" tweeter

    rear speakers
    are on hold till i purchase some 3/4 mdf and a table saw to fab up some plates to mount them on

    subwoofer amp
    kenwood excelon KAC-X301T

    pioneer Ts-sw1041d

    subwoofer enclosure
    pioneer UD-sw10b ( new box will be taller and narrower to maintain c.i. and fit in space available)
    this also has to wait for mdf and table saw purchase

    speakers and seaker am will probably end up being pioneer... i think

    as for wiring i will be running 4awg from the battery to alternator, starter, and grounds and 8awg for every thing else

    other work needs to be done before i worry about eclectic stuffing like getting a sub box that will wit completly behind the assenger seat, components for the doors... rear speakers are not ordered because i have to make mounts for them... and get the material to cover them...

    some rust repair exterior to the cab, replacing the dash mat, paint and body work, door panels, carpet and interior.... and lastly new door seals and window seals... before carpet goes down floor will be bed lined and some sound deadening layed on top of that... (im sure this thing will sound like a beer can with this shallow mount sub :( )
    Last edited: Feb 16, 2012
  5. jgilk1

    jgilk1 Full Member

    ok so after removing the stock alternator in perpetration to install the new dodge alternator i changed my mind on mounting location (2 reasons)

    with the installation of the v-belt pulley as apposed to the serpentine belt pulley that was on the dodge alternator it moved the pulley out of alignment from the crank and water pump about 1/8" so that was a no go... and i didn't feel like modifying or fabbing up a new bracket...

    second reason i removed the emissions pump from this truck about 2 weeks ago and the dodge alternator with less then 5 minuted on the grinder to the old emissions pump lower mounting bracket alternator bolted right in (with some modification to the tensioner bracket)

    so now this system will be running dual externally regulated alternators charging separate batteries the 30 amp alternator will be responsible for running the stock wiring... and the dodge alternator will be running the amps and any further electrical upgrades (fog lamps, the relay for the high-beam upgrade, second amp for components and ) as well this will eliminate any issues with twitching and flickering of headlights and what not from the amp...

    so with the above said i rewired in the stock alternator and it is running the 13.8v @ idle and 14.2v while running down the road...

    the thing i didn't take in to account last night when i was mounting in the alternator was the fact that i will need some way to excite the secondary alternator and regulate it??? i found a few articles on seperate topics on this but im not sure how i should go about this....

    reference post 5 this would be the setup for wiring if both alternators were excited

    second link is how to wire the dodge alternator to by pass the fact that the dodge alternator factory is controlled by the pcm

    the charging wire from the alternator is already (partially ran from the alternator to the second battery and the battery is grounded to the cab and chassis still need to clip the wire and install 150 amp anl fuse holder (ran out of solder to solder the crimped ends on) so all of the minor wiring is ran (and a temporary battery is temporarily mounted behind the drivers seat)

    any thoughts on how i can do this??? i am thinking right now that option 2 will work since there are different sized and brand alternators and 12v supply to excite the second alternator can come off the extra lead on the circuit breaker (i.e. the factory battery and alternator)???
    Last edited: Feb 18, 2012