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105 amp ALTENATOR 2500HD

Discussion in 'Chevy Trucks' started by millsaps118, Dec 3, 2007.

  1. millsaps118

    millsaps118 Senior Member
    Messages: 702

    First storm of the year and 30min into my first job while plowing I noticed my dash lights and head lights diming a little more than usual while operating the plow. I also noticed my plow was very slow and a few times I couldn't get it to raise all the way up. All my warning lights on the dash would light up and dim and the truck felt like it was going to stall. I was running my radio, heater, defrost, corner strobes, light bar, and had my cell plugged in. I had 12 more accounts ahead of me and this was not the time to figure out WTF was going on. I just put a new battery in a week before and (Napa Gold Series) new this couldn't be the problem since the battery is only used for initial start-up, so I figured it was the alternator. I call Napa with 4min to spare before they closed and caught another break with them having a 130amp alternator in stock, my OEM was 105amp so I upgrade. I ask them to drop it off for me at my shop and I make my way back there to put it in. I put it in and the way things are going for me so far my serpentine belt is to short now! So I call auto zone and they have a belt that will work, but they close in 5min. and can't deliver it!
    I grab another truck and race up there just before they were getting ready to lock the doors, put the belt on and button her up. Everything seems to be working fine now but my head lights still dim a little bit, not as much as before when I use the plow. I wanted to upgrade to the 160amp but that was special order and obviously I didn't have 4 days to wait for it. Should I get the 160amp or bigger or should I stick with the 130amp I just put in?
    Last edited: Dec 3, 2007
  2. Mark Witcher

    Mark Witcher Senior Member
    Messages: 605

    130 amp alt. is plenty if everything is working properly. I dont have any plow truck with more than that and have never had a problem in 17 years of plowing. And they are all single battery systems except for one diesel truck.
    Why did you have to buy a longer belt? I dont understand, this should not change. If your new alt has a larger diameter pulley than the old one, that will affect its low rpm amp output.
    How many years have you plowed with the 105 amp?

    If the pump motor is getting wornout it will pull alot more amps.
    Last edited: Dec 3, 2007
  3. millsaps118

    millsaps118 Senior Member
    Messages: 702

    Because the case on the 130Amp is slightly bigger than the OEM 105Amp. It made it taller by about 3/8" to allow more coiling.
  4. Q101ATFD

    Q101ATFD Senior Member
    Messages: 277

    You should look into putting a second battery in that truck. With all of the accessories you have, it's no wonder your lights went dim. Unfortunately, if your NAPA battery is not a "deep cycle" type, you probably took a few years off of your battery's life too.

    If you decide to put 2 batteries in, be sure to get 2 new ones. Search the forums for more info... However, with a 130 amp alternator, you would probably be alright with a single new yellow-top Optima battery.
  5. big bird

    big bird Senior Member
    Messages: 119

    i would go with the bigger alt had the same problem last year put a bigger alt in plug in a bunch of crap no dim the plow works good wesport
  6. pipepuller2002

    pipepuller2002 Junior Member
    Messages: 1


    I put a 145 amp alternator in my "05 diesel. Came from the factory with a 105 amp. Have had no problems with the 145 amp. Had to change belt as the bigger alternator was a smidge bigger in the case. Run strobes and two way radio and factory radio with no problems.
  7. Omaha Plowboy

    Omaha Plowboy Member
    Messages: 66

    My first job was rebuilding starters and alternators. You can get high output kits for most alternators, and they are very simple too install. If you don't want too try it yourself, check your local phone book for rebuild shops. Normally they can upgrade your alt. for alot less then the price of high output unit at the parts store.
  8. mikelawtown

    mikelawtown Senior Member
    from Mass
    Messages: 429

    What did the 130 amp cost you?(also what brand was it and what part # for the belt?...as i may be doing this soon also..Thanks
  9. millsaps118

    millsaps118 Senior Member
    Messages: 702

    Mike-- I got the alt from Napa Auto Parts, here's the like for the one I bought.http://www.napaonline.com/MasterPag...4807&Description=Alternator+-+Remfd+-+Premium. As far as the belt I can't find the invoice right now so I can't tell you the part # for that. I bought the belt at Auto Zone. You can get the belt anywhere, just tell them you upgraded your alt and need a belt the next size up from your OEM.

    Good luck.
    Last edited: Dec 3, 2007
  10. rdaily104

    rdaily104 Member
    from Indiana
    Messages: 35

    Having similar problem

    I have read all of these replys and was wondering how to tell what altenator is in my truck. I have a 05 GMC Sierra 2500 hd. I hooked up my plow yesterday and plowed for the first time. The lights went real dim. I had no problem with the plow working but lights bad. Any help would be great. Thanks
  11. calhoun

    calhoun Senior Member
    Messages: 165

    If you have plow prep package (2005) you have the 145 amp alternator. I believe it will be stamped right on the altenators case.
  12. bribrius

    bribrius PlowSite.com Addict
    Messages: 1,609

    my alt is a 105amp. everyone keeps saying i should replace it. When i use the plow the lights all dim. i just ignore it. I'm not running much for auxilliary lights just a led on the roof. I think that helps.
    Figure i will worry about it if it ever seems like its going to stop working.
  13. santelikk

    santelikk Member
    Messages: 67

    I had no problems with my 105 amp alt and the 2 batteries on my truck. It is a diesel and the batteries are 2 months old though.
  14. millsaps118

    millsaps118 Senior Member
    Messages: 702

    Like Calhoun said it should be on the alt. Might be on the back side so it might be hard to see.

    When you work the plow watch the voltage meter on the dash and see if it pegs out on the red. That will give you a good indication of how much juice your plow is really pulling from your alt. You could take it a step further and bring it into a shop and have 'em do a load test on it with the plow on. Keep in mind that the more and more you max out your alt it puts premature wear on it cuz it's trying to keep up with the voltage draw from the plow plus run all electrical on the vehicle. You defiantly don't want your alt taking a dump on you while out plowing, you'll be dead in the water and calling for a tow.

    My 105 worked fine last year but now I added a 6 head 90W strobe kit and run a light bar with 2 55W rotors that just runs off the 12V AUX plug, plus all my creature comforts in the cab are all on. I don't think I would have made it through the rest of the storm with the 105amp'er.

    Check into upgrading your alt, you can do it for around $300 with a new serp belt, it might save you time and money down the road. Just my .02:drinkup:
  15. tkrepairs

    tkrepairs Senior Member
    from maine
    Messages: 186

    i had been plowing for about 45 min or so and i noticed the same problem. i have the 130amp alternator included in the 2002 plow prep package. the lights had always dimmed before, and this time it just slowly got worse. turns out it was the battery in my case, i swapped it for the 800cca/1000ca optima red top and everythings back to normal. and just to help things out a bit im looking into getting a powermaster 200amp alternator at some point, i think that would help out the life of the battery a bit as well as the dimming lights and the strain on everything else that doesn't get the electrical supply it needs.

    for about $360 you get 200amps instead of 130/145.... maybe worth the extra $$$??? dunno but the 130amp doesnt cut it IMO.
    Last edited: Dec 7, 2007
  16. bersh

    bersh Senior Member
    Messages: 169

    Upgrading to a 200 amp alternator won't do you any good if you don't also upgrade all of your battery wiring to a larger gauge. The 145 amp alternator is about all the juice the stock wiring can handle, and as it is the factory should install heavier wiring on the trucks that get the higher output 130 & 145 amp alternators (not sure if they do, but I doubt it).

    I don't think the issue is the maximum capacity of the alternator, but is more a function of where the alternator makes its power. Most of these high ratings are based on a certain engine rpm (around 2500+ rpm). The key is to find an alternator that has a high idle rating. When you think about when most of us are moving the plow, it is when you're at idle, or at least at low rpm.

    Considering the cost of the 200 amp alternator and wiring upgrade, I'd think most folks would be better off and see more gain from installing a second battery.
  17. rdaily104

    rdaily104 Member
    from Indiana
    Messages: 35

    I like the idea of putting a second battery in. Where would you locate the second tray though. I don't see where there is room. Which battery do you guys recommend for my 05 Sierra.
  18. calhoun

    calhoun Senior Member
    Messages: 165

    The second battery goes over the front wheel against the fire wall. The fender brace is removed.This is a factory option and the parts depart will have all the parts if you want a stock installation.
  19. dmerrell89

    dmerrell89 Junior Member
    Messages: 4

    my dads duramax has 2 batteries and 2 alternators. Looking into adding a second one to mine.
  20. millsaps118

    millsaps118 Senior Member
    Messages: 702

    Just like calhoun said....If your looking at the truck from the front w/the hood up it would be located in the back corner pass. side up against the fire wall. Remove the fender support bracket and drop 'er right in.

    You want to use matching batterys, so buy the same one that's already in the truck if you plan on keeping your stocker. If not I have heard some guys here using Optimum Red Tops.
    Here's a good Thread by TLS on his install job on his '04 that Motorman 007 recently found. http://www.plowsite.com/showthread.php?t=23825
    Last edited: Dec 8, 2007