Jump to content

2016 Sierra 3500 Main and Aux batteries -

rebrecs

By rebrecs
in Troubleshooting & Recalls

 Share

Recommended Posts

rebrecs Enthusiast

rebrecs

Posted
Posted

Hi,

I need to understand how the main and aux batteries are related. There is only sparse information in the vehicle User Manual. I believe all of my questions would be answered if I could see a wiring diagram. I found a service manual for my make and model on Helm Inc.'s website. It costs $350.00

Before I spend the $350, I thought I would try this forum.

If there is anyone here who knows about the Aux Battery and is willing to chat with me about it - Your help will be greatly appreciated.

 

I want to know how the Aux Battery is situated in both the cranking circuit (if at all) and how the Aux Battery gets charged (charging circuit)

Additionally, a somewhat related question would be; What exactly is the Battery Gauge on the dash measuring? (main, aux, alternator, all 3, what?)

 

Thank you in advance for putting up with such a newbie question. Guessing about things makes for bad troubleshooting. Just want to understand what I'm dealing with before I go poking around.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Snowcamo Senior Enthusiast

Snowcamo

Posted
Posted

Im currently looking into this for my 1500. From what i understand the batteries are separated by this relay. Do you have a current sensor clamp on both neg battery cables? I am not for sure o. Which of the two the dash reads but I'd assume passenger side battery.23f220a1ca23fafd979ecbcdcf42a3ae.jpg

Sent from my LG-G710 using Tapatalk

rebrecs Enthusiast

rebrecs

Posted
  • Author
Posted
On 11/26/2019 at 9:06 PM, Snowcamo said:

Im currently looking into this for my 1500. From what i understand the batteries are separated by this relay. Do you have a current sensor clamp on both neg battery cables? I am not for sure o. Which of the two the dash reads but I'd assume passenger side battery.23f220a1ca23fafd979ecbcdcf42a3ae.jpg

Sent from my LG-G710 using Tapatalk
 

Thanks Snow, I'm sure I do. This is the first I have seen of the terminology "Aux Battery Relay." So far I have seen automatic charging relay (ACR) and Battery Isolator. Something new to investigate. Finding an explanation has turned in to actual work. I appreciate the info you provided. Its a good lead. (no pun)

rebrecs Enthusiast

rebrecs

Posted
  • Author
Posted

I have 3500 Diesel 6.6 Denali.

There is a battery charging management system built-in from GMC. Based on information in the Owners Manual under the "Battery Gauge" section, there is functionality sounding like what you would expect from a DC-DC Charger w/ Controller. However, the information only discusses the Main battery. There is no mention of how charging is handled for the aux battery anywhere in the Owners Documents. Including the Dura-Max Supplement. There is no charging controller listed on any parts breakdowns either. At this moment I am working from the assumption that either the logic is in the ECM, or the Aux Battery is a well guarded secret.

The cranking battery does have a large plastic box affixed to the top of the battery with a lot of high current wiring coming in and out of it. If there is a charging controller, that would be the place for it, and it would look about like that.

However, there is no mention of that box in any parts breakdowns either.

 

Do batteries come with big plastic boxes on top these days?

I was going to look up the AC-Delco battery model #, but the mystery box obscures the battery entirely. I can tell that changing that battery would not be a fun thing to attempt.

So far I have not been able to get that box open. I need a better flashlight.

 

 

davester Senior Enthusiast

davester

Posted
Posted
29 minutes ago, rebrecs said:

I have 3500 Diesel 6.6 Denali.

There is a battery charging management system built-in from GMC. Based on information in the Owners Manual under the "Battery Gauge" section, there is functionality sounding like what you would expect from a DC-DC Charger w/ Controller. However, the information only discusses the Main battery. There is no mention of how charging is handled for the aux battery anywhere in the Owners Documents. Including the Dura-Max Supplement. There is no charging controller listed on any parts breakdowns either. At this moment I am working from the assumption that either the logic is in the ECM, or the Aux Battery is a well guarded secret.

The cranking battery does have a large plastic box affixed to the top of the battery with a lot of high current wiring coming in and out of it. If there is a charging controller, that would be the place for it, and it would look about like that.

However, there is no mention of that box in any parts breakdowns either.

 

Do batteries come with big plastic boxes on top these days?

I was going to look up the AC-Delco battery model #, but the mystery box obscures the battery entirely. I can tell that changing that battery would not be a fun thing to attempt.

So far I have not been able to get that box open. I need a better flashlight.

 

 

From posts on another forum I frequent, the Duramax's have dual batteries hooked in parallel, so they charge/discharge at the same time.  It's not a "main battery/auxiliary battery" situation.  They both are the "main battery".

  • Like 1
rebrecs Enthusiast

rebrecs

Posted
  • Author
Posted
4 hours ago, davester said:

From posts on another forum I frequent, the Duramax's have dual batteries hooked in parallel, so they charge/discharge at the same time.  It's not a "main battery/auxiliary battery" situation.  They both are the "main battery".

I was beginning to suspect that. Now, things are beginning to make sense. Thank you for sending this along.

That sort of puts a new twist on "disconnecting the battery." I'll have think about that.

Snowcamo Senior Enthusiast

Snowcamo

Posted
Posted
From posts on another forum I frequent, the Duramax's have dual batteries hooked in parallel, so they charge/discharge at the same time.  It's not a "main battery/auxiliary battery" situation.  They both are the "main battery".
Anything on the 6.0 gas engine setup? I wonder if they are the same. Its really difficult to find any info on second battery/ alternator setups. I have been wondering if any reprogramming would be needed to to bcm.

Sent from my LG-G710 using Tapatalk

davester Senior Enthusiast

davester

Posted
Posted

No idea on the gas.  If they are hooked up in parallel, then there's no need to do anything special for the alternator, as it charges them both at the same time.

Gmman Enthusiast

Gmman

Posted
Posted

I have put the AUX battery in my gas truck. Really simple. I use it for my camper. I used all factory stuff. I didn't get all the parts from the dealer but they are all GM parts. On the 2500 its plug and play. I don't know about the 1500.

Quote

 

 

Snowcamo Senior Enthusiast

Snowcamo

Posted
Posted
I have put the AUX battery in my gas truck. Really simple. I use it for my camper. I used all factory stuff. I didn't get all the parts from the dealer but they are all GM parts. On the 2500 its plug and play. I don't know about the 1500.
 
 
What's interesting is my 1500 came with a second battery tray from the factory. Do you have the relay in line with the batteries?

Sent from my LG-G710 using Tapatalk

  • Like 1
Gmman Enthusiast

Gmman

Posted
Posted

Yes. I have the one pictured above and the battery harness has a small square one attached to it as well. Mine had what looked like a battery tray as well, but it really isn't. These are the new battery tray parts.

image.jpg

Gmman Enthusiast

Gmman

Posted
Posted

I went to dealer lots and looked at trucks that had snow plow packages and  told them I was working on a project and could I look under the hood and got some # that way and the it all started to fall into place.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • bluemonstercali
      wipers come on randomly

      By bluemonstercali · Posted

      I am experiecing the same issue, I have gone in the setting and disabled rain sensing function but I am still experiencing this. Whe i use my turn signal they will redomly turn on. Sometime they stay on and others times we swipe 2 or 3 times and stop. Its super anoying, escpecially after a fresh wash. Anyone have any advice? . rain-sensing function, but I am still experiencing this issue Sometimes they stay on, and other times we swipe 2 or 3 times and stop.It's super annoying, especially after a fresh wash.When I use my turn signal, they will randomly turn on. I am experiencing the same issue. I have gone into the settings and disabled the rain sensing function, but I am still experiencing this.
    • Grumpy Bear
      Gas Prices

      By Grumpy Bear · Posted

      If we actually used any significant amount of that source in the USA then I'd agree but we don't. We've had that discussion before. We drill and pump more than we use. Thing is, we sell. We export. Gas and Crude. It's more profitable so any shortage here is self inflicted and LEGAL.    I worked a gas plant that has multiple fuel sources available and I worked in the furnace and boiler plant in that facility. I'd had days we swapped fuel types four times in a twelve hour shift which isn't done on supply but on margin. Two of the fuel sources are internally generated. Tail gas and DAK, both of which are sold as well a consumed. We always had more than we needed to run the process but we chose the fuel that produced the best margin not bought at the cheapest price always. A good bit of math to that and back in the time that was done on a slide rule.     I worked the Shale Oil Semiworks of Chevron Research and CONOCO Research in Salt Lake City. That process never went into production although it was very successful. Why? Did we lack oil bearing shale? Nope. Price of crude never made the margins work. That was in the late 70's early 80's. Remember history? What was happening then was a reaction to that situation. It didn't drive it. If so then it's easy. This isn't a supply and demand thing. This is a profit and margin thing and AI rules that now.    In no refining situation that I was ever in would a bomb hitting a well anywhere in the world 'instantly' interrupt or even distress the supply. Most plants have more than a months worth of crude in the tank field and more in pumping stations. That yo-yo could play out over days, weeks and maybe months and have zero impact on plant operations. How many times has this been off and on in the last few months? These people and not stupid. These plants measure down time in hundreds of thousands of dollars per day. They are not sucking fumes or waiting on the next truckload with baited breath. Besides, as I noted, they are for the most part 'vertically integrated'. They own it from the dirt is sits in to the delivery rack and sometimes to the pump. It has a HUGE shock absorber built in. When production suffers, refining wins and when refining is winning exploration is killing. The rest of that crap in the news is a 'news cycle'. Government dipping in to reserves? Oil is stealing their milk money. There's a reason Chevron abandon Venezuela infrastructure and it had nothing to do with security of US citizens. Nationals run those plants. it has to do with MARGINS disappearing to corruption. They are in no hurry to return. Is there supply there? Oh yea. More than enough to offset what is bought in the middle east. Just isn't ???? Profitable.    We have supply. There are places in Illinois you can drive a pipe into the ground and run your homes natural gas furnace on it.    A refinery fire will gum up the supply works but not a localized war where the market is using a limited supply from. Now Europe, that's something other....
    • CamGTP
      Gas Prices

      By CamGTP · Posted

      $4.00 a gallon here now.   Diesel nearly $5.00 again.
    • Atlas
      Gas Prices

      By Atlas · Posted

      If we're talking futures, yes, it's speculation.   The spot price of a delivered barrel is elevated now compared to before the conflict. And that is related more to current supply/demand.
    • Grumpy Bear
      Gas Prices

      By Grumpy Bear · Posted

      SPECULATION on the wars effect raised prices. AI is maximizing the profit. Refining is vertically integrated. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...