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Alternator or Battery?

Discussion in 'Chevy Trucks' started by wsmm, Jan 16, 2011.

  1. wsmm

    wsmm Member
    Messages: 80

    Running stock alternator, recently new battery. 1990 Chevy 1/2 ton with 4.3l v-6. When lifting my plow I notice that my voltmeter drops way down, does an immediate recovery to normal 14 volts when I release the switch. Battery does not seem to run down and seeing as I only use this vehicle for plowing I keep it on a maintenance charger when not being used. Do I need to go to a double battery system, or a larger alternator, or just leave it as is?

  2. sweetk30

    sweetk30 PlowSite.com Addict
    Messages: 1,588

    totaly normal for the huge plow motor draw for the system to do that.

    if you want to help it a tiny bit add a 2-4 gauge wire drict from battery hot to the back stud on the alt for the output. the stock wires are not realy designed for the extra load pulls from the plow pump / winches / and other things we add to the systems.

    if you want also thay offer a 105 amp alt option over the counter. but this wont help much . as alt's only put out full load at spec rpm's and thats not at 800 rpm when your stoped in the snow pile .

    on the shop ford plow truck at were i use to work i swaped on a smaller by 1/8" pulley on the alt to spinn it faster. this helped as 90% of the plowin there is short parking lot runs at the car repair shop/sale lot. after 1hr with stock my battery was droppin . when i swaped the pulley and shorter belt i never had the problem again.

    but i wouldnt recomend the smaller pulley on a street drivin truck that see's reg high rpm style drivin as the alt will be spinnin way to fast for the life span.