Alternator Sizing

Discussion in 'Truck & Equipment Repair' started by vegaman04, Feb 18, 2008.

  1. vegaman04

    vegaman04 Senior Member
    Messages: 372

    Ok, I know Iraggi makes some great alternators but what would be ideal for a diesel w/ two batts with a plow - 200amp, 240, 280 or is this excessive?!? Now put a vista lightbar on. What would be ideal in my question in different situations. Is there like a rule of thumb to go by for sizing?

    Thanks in advance!
    Last edited: Feb 18, 2008
  2. dirtyedge

    dirtyedge Junior Member
    from se WI
    Messages: 12

    Unless your stock alternator is junk, I don't see any reason to replace it. It should put out enough juice to charge your 2 batteries while plowing and with lights on.

    Especially with two batteries because it won't drain them down as much per cycle.
  3. nevrnf

    nevrnf Senior Member
    Messages: 455

    200 - 250 will cover you. The factory alt was sized to cover the electrical needs of a STOCK truck. It was not intended for the plow, warning lights, aftermarket stereo, 2 way radio, ect. Look at your plow mfr's spec for electrical consumption and add it and any other accessories to your factory # then add at least 10 %. I usually add 20 % just for safty sake. I would rather have my electrical system work @ 50% of capacity than 80%. It gives you a better margin of safety from overload.