# alternator upgrade on duramax?



## cdahl1177 (Jan 17, 2011)

i have an 06 chevy duramax that im getting ready to put a boss 9'2" VXT on. im trying to do as much research as possible before i spend the money. i do not have the plow prep package and im out of warrenty so im just going for it. i have upgraded almost everything on the front end suspension and now im turning to the electrical system. so to get to the point, does anyone have problems with stock alternators and if so whats the solution you came up with to fix it. thanks for the help.


----------



## tuney443 (Jun 25, 2006)

cdahl1177;1211471 said:


> i have an 06 chevy duramax that im getting ready to put a boss 9'2" VXT on. im trying to do as much research as possible before i spend the money. i do not have the plow prep package and im out of warrenty so im just going for it. i have upgraded almost everything on the front end suspension and now im turning to the electrical system. so to get to the point, does anyone have problems with stock alternators and if so whats the solution you came up with to fix it. thanks for the help.


I have the same truck as you and plow also,just not the VXT version and will tell you just leave it alone.The one thing I changed however under advice from B&B is that battery cable which is actually a fusible link from the driver's side battery going to the alternator.I installed a 4 ga. cable there with a Napa Megafuse 200Amp I believe.


----------



## NICHOLS LANDSCA (Sep 15, 2007)

To help you feel better, the Dmax trucks didn't have a plow prep option because they have it.


----------



## musclecarboy (Aug 19, 2007)

tuney443;1211841 said:


> I have the same truck as you and plow also,just not the VXT version and will tell you just leave it alone.The one thing I changed however under advice from B&B is that battery cable which is actually a fusible link from the driver's side battery going to the alternator.I installed a 4 ga. cable there with a Napa Megafuse 200Amp I believe.


Why is this suggested?


----------



## Q101ATFD (Oct 24, 2006)

musclecarboy;1211906 said:


> Why is this suggested?


It's suggested because the stock cable is undersized for the output that the alternator is capable of putting out. At higher amperages, the voltage at the battery can be 5% to 7% less than the output from the alternator. That means inefficient charging.



NICHOLS LANDSCA;1211874 said:


> To help you feel better, the Dmax trucks didn't have a plow prep option because they have it.


Yes, they already have the upgraded alternator, but the main reason that some Duramax trucks didn't have the P/P option is because of the weight limitations on the front end. The 2001-2007 D/A trucks had the P/P as an option on regular cab and extended cab/short bed configurations.


----------



## captadamnj (Jan 20, 2004)

You are about to spend $5k-$6k. Can the stock alternator get you by if you aren't running other heavy loads (salter, light kits, amp, etc.)? Probably. But for another $300 you can put on an alternator that will put out more amps at lower rpms and have a greater cooling capacity for itself = longer life. Plus $10 for the aforementioned cable. It bolts right in, it was a no brainer for me. Plus I have a spare alternator sitting in my garage should I have a problem.

Search high output AD244 and you'll find plenty of options.


----------



## cdahl1177 (Jan 17, 2011)

thanks for the help. if figured it makes sense to upgrade as much as possible before putting the plow on.


----------



## RBRONKEMA GHTFD (Dec 17, 2006)

NICHOLS LANDSCA;1211874 said:


> To help you feel better, the Dmax trucks didn't have a plow prep option because they have it.


Mine doesn't. I have the 105 alt in mine and no roof provisions for a warning light.


----------



## Raconteur (Oct 3, 2010)

You should find out if you can use a Leece-Neville 200 or 220 Amp Alt


----------



## Philbilly2 (Aug 25, 2007)

RBRONKEMA GHTFD;1213032 said:


> Mine doesn't. I have the 105 alt in mine and no roof provisions for a warning light.


your duramax has a 105amp alternator???????? from the factory?


----------



## RBRONKEMA GHTFD (Dec 17, 2006)

Yup I looked up the build sheet off line and thats what it showes on here. The build sheet shows a K68 in the RPO. And it says ampere 105. No VYU in the RPO. I also don't have a aux button. Meaning no plow prep. I think when this one goes I am going to get dual 145s.


----------



## Philbilly2 (Aug 25, 2007)

wow, I didn't know that you could even get a duramax with only a 105amp alternator. Every one I have ever had or been under the hood of has had a 145 amp (K3G in the RPO) Including all of them that don't have the plow prep package. Well, I guess that you learn somthing new everyday.


----------



## tuney443 (Jun 25, 2006)

cdahl1177;1212723 said:


> thanks for the help. if figured it makes sense to upgrade as much as possible before putting the plow on.


Go ahead and spend your money but if you have the 145 amp. alternator,it is pure overkill.My truck is loaded for bear,accessories on,lights on,flashers on, light bar on,heater on,sometimes I even use the all electric salter while plowing, and the plow is working fine. Your .02,not mine.Just 10 years ago,a 100 amp. alternator was considered huge,a 145 amp. job is a serious charger.


----------



## RBRONKEMA GHTFD (Dec 17, 2006)

Philbilly2;1213737 said:


> wow, I didn't know that you could even get a duramax with only a 105amp alternator. Every one I have ever had or been under the hood of has had a 145 amp (K3G in the RPO) Including all of them that don't have the plow prep package. Well, I guess that you learn somthing new everyday.


i was under that assumtion also until I read the build sheet. I do know also my truck was built in Pontiac, Mi.


----------



## Mr.Markus (Jan 7, 2010)

My 07 came with twin 125 amp alternators and power is never a problem. I highly recommend it.


----------



## cubicinches (Oct 19, 2008)

Mr.Markus;1214702 said:


> My 07 came with twin 125 amp alternators and power is never a problem. I highly recommend it.


X2...

Ya can't beat two of 'em!

You can buy the parts right from GM to add one. I did it with my '08 LMM.

I ordered my '11 LML with twin 125's.


----------



## EXR (Apr 1, 2009)

My NBS dmax needs a bigger alt. I have had my truck not start 2x this winter already and many times barely start (always plug in the block heater night b4). Had the batteries and alt check and is working fine. My truck doesn't have PP and with that I assume a bigger alt. I am resorting to putting my trickle charger on after I get home every time I plow to keep it charged. Sux, but its what I have to do. I'm thinking of getting a bigger alt. soon..this is a pita.
Guy Ive partnered with has had the same problem with his powerstroke..it actually died idling at Tim's one night..every heard a ford diesel die out..not a pretty sound. He upgraded to a 200amp alt with no issues since.


----------



## Philbilly2 (Aug 25, 2007)

EXR;1215850 said:


> My NBS dmax needs a bigger alt. I have had my truck not start 2x this winter already and many times barely start (always plug in the block heater night b4). Had the batteries and alt check and is working fine. My truck doesn't have PP and with that I assume a bigger alt. I am resorting to putting my trickle charger on after I get home every time I plow to keep it charged. Sux, but its what I have to do. I'm thinking of getting a bigger alt. soon..this is a pita.
> Guy Ive partnered with has had the same problem with his powerstroke..it actually died idling at Tim's one night..every heard a ford diesel die out..not a pretty sound. He upgraded to a 200amp alt with no issues since.


Who checked your batteries?

Sounds to me like you have a different problem. Somthing is draining your batteries while you truck is off. (Radar detector?, tom tom?, phone charger?) A bigger alternator will you no good as your truck will not charge when the motor is off.


----------



## tuney443 (Jun 25, 2006)

Philbilly2;1216688 said:


> Who checked your batteries?
> 
> Sounds to me like you have a different problem. Somthing is draining your batteries while you truck is off. (Radar detector?, tom tom?, phone charger?) A bigger alternator will you no good as your truck will not charge when the motor is off.


X2--definitely needs some testing.


----------



## Mr.Markus (Jan 7, 2010)

Philbilly2;1216688 said:


> Who checked your batteries?
> 
> Sounds to me like you have a different problem. Somthing is draining your batteries while you truck is off. (Radar detector?, tom tom?, phone charger?) A bigger alternator will you no good as your truck will not charge when the motor is off.


Funny story.... I once had my battery draining on my 96 while it was parked, could not figure it out, until one morning I noticed a shadow below my front axle. Turns out the mercury switch for my underhood light was pooched and turned the light on constant. Stupid little thing but what an aggravation.


----------



## EXR (Apr 1, 2009)

GM dealer checked out my batteries..CAA did a check on the batteries and charging system..all came back aok.

I was told that because I'm running a plow/light/salter and not spinning the engine up much the alt isn't charging the batteries enough. So when I return home and park the truck there isn't enough juice to turn it over or barely enough.

I'm taking it in to the dealer this time to get the charging system checked.

Think I might do a thicker cable upgrade to the alt with inline fuse..read that somewhere on this site.


----------



## RBRONKEMA GHTFD (Dec 17, 2006)

EXR;1218262 said:


> I was told that because I'm running a plow/light/salter and not spinning the engine up much the alt isn't charging the batteries enough. So when I return home and park the truck there isn't enough juice to turn it over or barely enough.
> 
> 
> > I have a hard time believing that. I run 2 plows on my truck. 4 led work lights and also a overhead light. My truck has never had a issue with it not wanting to start. Even when its colder than a witches t!t out. I don't even plug my truck in at night because of the plug issue on the D-maxs and my truck sits outside. I think you have something draining your battery. Some thing on your plow or you have a loose connection somewhere. Hitting the gas a few time before you shut it off wont turn that alt that much to make a difference.


----------



## MrPLow2011 (Jan 14, 2011)

Hey mucsle car boy. Diesel do not have an ignition system like you cars do. So they are not powering a distributor and plugs. Once its started its combustion at 22-1 becuase of pressure. It needs the 2 batterys to start it. But after that it doesnt require all that much to run. Its fuel on-off after its started. dont worry about the alternator on a diesel unless you plan on going nuts with strobes.


----------



## tuney443 (Jun 25, 2006)

EXR;1218262 said:


> GM dealer checked out my batteries..CAA did a check on the batteries and charging system..all came back aok.
> 
> I was told that because I'm running a plow/light/salter and not spinning the engine up much the alt isn't charging the batteries enough. So when I return home and park the truck there isn't enough juice to turn it over or barely enough.
> 
> ...


Change the cable from the DS battery to the alternator to a 4 gauge and get a Megafuse 200 amp. fuse with holder from NAPA.That extremely small gauge black cable which is your fusible link isn't really meant for a plow setup.There's a convenient threaded hole already there on the aluminum casting to mount that rubber fuse holder.


----------



## cubicinches (Oct 19, 2008)

MrPLow2011;1218589 said:


> Hey mucsle car boy. Diesel do not have an ignition system like you cars do. So they are not powering a distributor and plugs. Once its started its combustion at 22-1 becuase of pressure. It needs the 2 batterys to start it. But after that it doesnt require all that much to run. Its fuel on-off after its started. dont worry about the alternator on a diesel unless you plan on going nuts with strobes.


What you're saying is true of an old mechanically injected John Deere tractor... but certainly not true of a Duramax, or any other modern day electronically controlled diesel engine. First off, the stock ignition system on a gasoline engine draws very little current anyway. Accessories aside, the fuel system of any modern day EFI engine is what draws the most current when the engine is running. A Duramax is no different from a gas engine in that respect... Electric fuel pump, electronic fuel injectors, electronic fuel rail pressure regulator, fuel injector control module, and an ECM to run it all. Start adding accessories and an electric over hydraulic snowplow, and you need every bit of charging power and battery reserve you can get... just like in any snowplow truck, gas or diesel.

Oh... and the compression ratio of a Duramax varies from generation to generation, but they range from 16.8:1 to 17.5:1.


----------



## sdplowing (Oct 7, 2006)

tuney443;1218968 said:


> Change the cable from the DS battery to the alternator to a 4 gauge and get a Megafuse 200 amp. fuse with holder from NAPA.That extremely small gauge black cable which is your fusible link isn't really meant for a plow setup.There's a convenient threaded hole already there on the aluminum casting to mount that rubber fuse holder.


Would that wire going bad cause my lights to really dim when I run the plow?


----------



## tuney443 (Jun 25, 2006)

sdplowing;1222597 said:


> Would that wire going bad cause my lights to really dim when I run the plow?


That fusible link cable isn't going ''bad'',it's simply not able to keep your charging system up to par while plowing because it's not heavy enough for an electric plow set up.So the answer to your question is very possible it is that cable.


----------



## jklawn&Plow (Jan 8, 2011)

Thin wire causes higher voltage drop. Motor then needs more current with the lower voltage to reach same power which causes more voltage drop. Kind of like thermal runaway.


----------

