# 105 amp ALTENATOR 2500HD



## millsaps118 (Aug 13, 2006)

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?


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## Mark Witcher (Feb 21, 2004)

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.


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## millsaps118 (Aug 13, 2006)

Mark Witcher;444586 said:


> 130 amp alt. is plenty. 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.


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.


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## Q101ATFD (Oct 24, 2006)

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.


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## big bird (Nov 12, 2007)

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


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## pipepuller2002 (Nov 21, 2007)

*alternator*

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.


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## Omaha Plowboy (Feb 11, 2007)

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.


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## mikelawtown (Dec 5, 2004)

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


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## millsaps118 (Aug 13, 2006)

mikelawtown;444966 said:


> 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


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.


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## rdaily104 (Nov 22, 2007)

*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


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## calhoun (Oct 18, 2003)

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


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## bribrius (May 5, 2007)

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.


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## santelikk (Sep 27, 2007)

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.


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## millsaps118 (Aug 13, 2006)

rdaily104;447512 said:


> 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


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



bribrius;447750 said:


> 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.


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


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## tkrepairs (Nov 28, 2007)

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.



> 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


for about $360 you get 200amps instead of 130/145.... maybe worth the extra $$$??? dunno but the 130amp doesnt cut it IMO.


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## bersh (Dec 12, 2003)

tkrepairs;448687 said:


> 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.


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.


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## rdaily104 (Nov 22, 2007)

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.


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## calhoun (Oct 18, 2003)

rdaily104;449481 said:


> 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.


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.


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## dmerrell89 (Nov 16, 2007)

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


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## millsaps118 (Aug 13, 2006)

rdaily104;449481 said:


> 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.


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


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## rdaily104 (Nov 22, 2007)

That cool. I might have to try that. I was looking at sears, at the Diehard Platnium any comments on that battery or another favorite? I just think there has to be a cheaper option then the Diehard. They want 184.00 for that battery.


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## lawn king (Nov 21, 2004)

My new duramax has twin 125's, i should have enough power to light up a ballpark!


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## millsaps118 (Aug 13, 2006)

Pretty much all diesels have 2 battery's. Those engines are harder to start vs gas motors in the winter so they need 2x as much cca's to turn 'em. Take a look at tractor trailer rigs, they have as many a 4 battery's. When you add multiple battery's it's primarily used for the cca's.


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## millsaps118 (Aug 13, 2006)

lawn king;450757 said:


> My new duramax has twin 125's, i should have enough power to light up a ballpark!


Your talking about dual alt's right......


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## lawn king (Nov 21, 2004)

Yes 2 alternators.


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## millsaps118 (Aug 13, 2006)

lawn king;451577 said:


> Yes 2 alternators.


Must be a Reg. cab right.........


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## rdaily104 (Nov 22, 2007)

Alright guys, I put in new battery. A Optima Red top. It did help out alittle, but still is dimming the lights more than I like. I checked into the second battery from the dealer and the price was outragous. The tray,clip,cables and relay was going to be 200.00. Any help!


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## santelikk (Sep 27, 2007)

rdaily104;453006 said:


> Alright guys, I put in new battery. A Optima Red top. It did help out alittle, but still is dimming the lights more than I like. I checked into the second battery from the dealer and the price was outragous. The tray,clip,cables and relay was going to be 200.00. Any help!


Go to a junk yard and get the parts for a fraction of the price.


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## millsaps118 (Aug 13, 2006)

rdaily104;453006 said:


> Alright guys, I put in new battery. A Optima Red top. It did help out alittle, but still is dimming the lights more than I like. I checked into the second battery from the dealer and the price was outragous. The tray,clip,cables and relay was going to be 200.00. Any help!


That sounds about right.....IF he included the xtra Red Top . The tray is like $26, go to your local auto parts store and buy cables and connectors for less than $30. The longest cable your going to need is the power, the NEG. is going right to the engine or chassis. Why do you need a relay???? Your going to be wiring in series. Then get a matching battery. Considering you have a Red Top that sounds about right. You should use matching batteries.


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## rdaily104 (Nov 22, 2007)

The price is for everything except the battery. The tray, holder, cables and relay is like 220.00. I was wondering if anyone else needed the relay. I looked at the other posts and no one has said anything about a relay. How long do you think the positve needs to be? And where is the easiest place to connect the negative too. Lastly, can I get a tray from the auto parts store or should it be from GMC?


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## millsaps118 (Aug 13, 2006)

rdaily104;453588 said:


> The price is for everything except the battery. The tray, holder, cables and relay is like 220.00. I was wondering if anyone else needed the relay. I looked at the other posts and no one has said anything about a relay. How long do you think the positve needs to be? And where is the easiest place to connect the negative too. Lastly, can I get a tray from the auto parts store or should it be from GMC?


Your dealer's smoking crack......you should be able to do it all WITH the RED TOP for around $200. You do not need a relay, you'll be hooking up your batteries in "SERIES" (one to the other) doubling your CCA's.

GO BACK TO POST #20 IN THIS THREAD and click on the link.


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## B&B (Nov 4, 2006)

millsaps118;453606 said:


> you'll be hooking up your batteries in "SERIES" (one to the other) doubling your CCA's.
> 
> GO BACK TO POST #20 IN THIS THREAD and click on the link.


You mean "parallel" (pos to pos. neg to neg) not "series" (pos to neg. neg to pos)..

Wiring them in "series" will give you 24V.

Common mis-terminology I know.


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## lawn king (Nov 21, 2004)

millsaps118;452489 said:


> Must be a Reg. cab right.........


Yes, its an 08 ,3500 HD regular cab.


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## TLS (Jan 31, 2000)

As per my post (mentioned earlier) you don't need/want to use the factory setup for dual batteries.

You do need the tray, the hold down clamp and bolt. Should still be under $30 at your dealership.

You then need lengths of wire and crimp on ends.



After reading this thread, I continually hear about dimming headlights when raising plow. If your experiencing this, the biggest alternator in the world won't prevent this. You need battery capacity. Dual 1000cca matching batteries hooked up in parallel will do the trick.

I plowed many years with 55 and 70 amp alternators and single batteries.....dimming lights are part of the job.


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## millsaps118 (Aug 13, 2006)

B&B;453972 said:


> You mean "parallel" (pos to pos. neg to neg) not "series" (pos to neg. neg to pos)..
> 
> Wiring them in "series" will give you 24V.
> 
> Common mis-terminology I know.


Thanks for the correction B&B.....you knew exactly what I ment.


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## B&B (Nov 4, 2006)

millsaps118;454265 said:


> Thanks for the correction B&B.....you knew exactly what I ment.


Yep, I did... just concerned about someone else that's all... don't want them trying to run their 12V truck on 24V...as bad things happen when you do that... I've seen it and it ain't pretty.


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## rdaily104 (Nov 22, 2007)

I wanted to make sure I have this right before I try this. I want to mount the extra battery plate then connect the positive to the other battery positve. I connect the negative off the extra battery to the engine frame or block. Should I keep the selnoid for the plow attached to the primary battery or move it to the back up battery? I am forgetting anything??? Thanks again for the help......


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## B&B (Nov 4, 2006)

For the most part you are correct. Pos to pos and neg to neg. 

You can connect the neg on the second battery to the engine (not the frame) but if you do, you need to also upgrade the stock ground cable between the stock battery and the engine or it will become the weakest link in the system as far as resistance goes, the stock cable isn't large enough for the job. 

If you don't want to upgrade the stock ground cable, then just run the ground from the second battery right to the stock battery...

You want to keep the plow power wire connected to the stock battery...


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## rdaily104 (Nov 22, 2007)

Thanks again for the info. I think I will just run the cables over to the main battery. I do understand the lights will dim some. I was told by a friend of mine that it is normal for the volts to drop but should recover quickly. What would you guys say is safe number for the volts to drop... I believe my has dropped to 10 then return to normal quick.


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## rdaily104 (Nov 22, 2007)

Guys,
I tried to put in the second battery, I got everything hooked up and no power at all. I disconnected the aux. battery and the truck fired right up...


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## B&B (Nov 4, 2006)

Then one of the connections you made at the stock battery wasn't making good contact...that's the only way it could have caused it to be dead.


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## hadley-plow-guy (Dec 18, 2007)

I would also reccommend installing a voltmeter if your truck doesn't come with one. Watch the voltage and if it drops below 12v's, time to upgrade to a bigger alternator. Oh and an ammeter wouldn't hurt either. It's a good way to keep tabs on things.


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## rdaily104 (Nov 22, 2007)

I got to tell ya. I love this site. I installed the dual batteries and it works great. The lights still dim alittle but the volts return very quickly. I would suggest to everyone that is gong to do this, make sure you get the tray from the dealer. I first tried generic tray from autozone. Big mistake! Once I got the tray it work great and very easy to do.......


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## millsaps118 (Aug 13, 2006)

rdaily...take some pics and let us seeeee


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## rdaily104 (Nov 22, 2007)

I will take some today and hopefully get them up in the next day or so.


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## Added Touch (Nov 10, 2006)

Well, looks like I'm not alone.... How come out of 3 plow distributors, none of them suggested upgrading my alt when I was quoted and had my plow installed? Doesn't make any sense!!!! Seems pretty common knowledge amongst those of you who have had any exp. plowing. Very frustrating. 

If I have understood some of the posts I have read then plowing a few nights were the dimming etc. happens is basically killing my battery?

Also, last night I forgot to switch the plow controller off for abot 6 hours and had zero juice left .... is that a typical situation, or should that be ok?

Thanks again, as always you all are agreat help! Good luck and Merry Christmas!


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## rdaily104 (Nov 22, 2007)

I have left my controller on all day and never had that problem. I try not to do it just for the fact of draining the battery but it has happened. Duel batteries, I'm tellin ya it works. I would try that before I changed out altenators...


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## BigLou80 (Feb 25, 2008)

B&B;453972 said:


> You mean "parallel" (pos to pos. neg to neg) not "series" (pos to neg. neg to pos)..
> 
> Wiring them in "series" will give you 24V.
> 
> Common mis-terminology I know.


If only they would start making the trucks 24 volt all these problems would go away. you plow would work faster, with smaller cheaper wires and less dimming of the lights. My old truck is 6 volt my current one is 12 and I hope my next one is 24

Lou


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## B&B (Nov 4, 2006)

BigLou80;542707 said:


> If only they would start making the trucks 24 volt all these problems would go away. you plow would work faster, with smaller cheaper wires and less dimming of the lights. My old truck is 6 volt my current one is 12 and I hope my next one is 24
> 
> Lou


There's been talk amongst the auto industry for the last several years to start equipping vehicles to an industry standard 42 volts across the board due to the ever increasing electrical demands placed on them, as well in the coming years.

Many of the auto manufactures want to convert to drive by wire brake and steering systems, but until they upgrade (as well as standardize) the voltage on the new cars and trucks, it isn't going to happen...yet.


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