True® GMC Sierra Dual Battery Kit 12V 140A Automatic Management

(8 customer reviews)


The True® brand is the best smart battery isolator kit for the GMC series! Made in the USA, the True® – GMC® dual battery kit is a heavy-duty 12v & 14A battery management system known for being compact, easy to install, waterproof, and heat-resistant. The new transparent case makes the glowing LED light inside much easier to see when the unit is active.


SKU: DBK12LRG-GMC Category:


This 9th generation 12v heavy-duty GMC Sierra dual battery kit is a superior product that uses a very unique designed and programmed SBI (PEP) when it comes to dealing with the stator charging mechanism.

A TRUE exclusive!

Here are some of the GMC Sierra dual battery kit advantages:

  1. It is assembled in America and delivers through first-class mail.
  2. It has advanced specific internal programming for maximum efficiency with automotive stators. (PEP)
  3. Its new case was introduced last April 2019 specifically designed for automotive application.
  4. It has a superior cable construction with 100 % waterproof shrink tube.
  5. It offers extra flex cables for easy routing.
  6. It assures correct cable ends to custom fit isolator studs.
  7. The new smart GMC Sierra dual battery kit can be left suspended in-line, as long as it is mounted with provided 3M Dual Lock™, or hard mounted with any provided screws.
  8. It is compatible with all battery types like dry cell, flooded lead-acid, AGM, and any hybrid.

With its upgraded features, the TRUE Smart 12v isolator switch is specifically designed and programmed for automotive and marine application, plus it is  100% American-made.


An important note from the designer:

“The TRUE® 12v battery isolator switch is the 9th generation I have designed. The first-generation products which I have designed before I figured the proper programming include the QUAD BOSS/AOPEC/Keyline units.

Together with PEP (Propriety Efficiency Programming), the all-new TRUE® isolator kits have added lots of upgrades which include the case design, circuit board design, and the type of cables that should be used in order to avoid insulation and terminal failures from possible corrosion.

 Overall, its main goal is to provide stable and easy installation. The construction of the actual 12v GMC Sierra dual battery kit case has been exclusively redesigned for automotive application which then allows a hassle-free and versatile installation. There are possible cable access slots that need to be “knocked out” because it may cause a breach in the seal protecting the circuit board, which is why the front mounted studs are there to eliminate unnecessary holes.

Now, we made sure to move all our production processes as possible to America. These improvements made huge impacts that are essential for the benefit of all because we only aim to provide the best and most efficient products that fit the standards and demands of a vehicle’s owner. True is a heavy-duty and universal dual battery kit for Sierra, Yukon, Terrain, Canyon, Acadia, Sabana. Yes all GMC® motors are fit for the True® brand. 

Dennis M. Hogan, Ph.D.
TrueAm Inc.


(These videos are not endorsed or represented as an “Official Installation video” by True Amalgamated and True Amalgamated accepts no responsibility for its content. It is produced by the end-user as stated. Follow entirely at your own risk.)



Dual battery setup with isolator kit in RV

2019 GM Truck dual battery setup video

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Additional information



8 reviews for True® GMC Sierra Dual Battery Kit 12V 140A Automatic Management

  1. Noah Johnson

    This was installed in a full-size 2010 GMC Sierra, along with a marine battery as the backup. It was simple to set up and works perfectly. The package had everything. The only difference was that I soldered the eyelets onto the wire rather than crimping them. That may be accomplished by heating the eyelets with a tiny butane flame and just feeding the solder in until it is bonded. Crimping provides a better electrical contact.

  2. Oliver MIller

    True battery isolator is a local company in USA, and I was impressed with how easy it is to use and how complete it is.

    The only thing you need to add as a safety precaution, as they propose, is an extra inline fuse coming from the second battery, preferably a 100-140amp fuse.

    Which I obtained after viewing a couple setup videos on YouTube.

    April 5, 2023

  3. Joeseph Florence

    Every time I go home, I have to turn on the trickle charger for my two series batteries so my truck will start up the following day. My air compressor kicks in most of the time, therefore I have to flick the key multiple times to start the truck.

    I initially believed that I might need to purchase a new starter, but after using the Sierra 1500 battery isolator, the vehicle has been starting for the past three weeks without the trickle charger on. The product functions properly.

  4. EmerTiu

    This is a great dual battery kit. I put USB ports, an inverter, and a second 100 amp Renogy AGM battery in the back of my GMC Sierra 1500 canopy. Simple wiring with unambiguous directions.

  5. Correy F

    Arrived with every detail I needed to put a dual battery kit in my Sierra 1500 to power all of my accessories, which made me very happy.

  6. Steve Hoggen

    This was just what I wanted in order to keep both of the batteries in my truck charged. The cord was adequate to connect my starting battery to the batteries at the back of my extended full-size truck.

    The True smart battery isolator for GMC Sierra 1500 worked beautifully, even after I exhausted my batteries twice and traveled countless rough gravel roads. Solar receives a lot of interest, but this is far more beneficial.

  7. Ryan

    Really simple to install.
    My only issue is the positive terminal on my main battery. I cut it off to use one of the new battery clamps. Well, the old one is a drop style as it runs over the battery. The ones in the kit don’t allow for this. Long story short. I had to rotate my battery 180 to make it work.

    Other than that, this kit is super easy and quick to install. Works well too.

  8. Ricky Hawker

    This merchant makes an excellent product. All of the gear and wiring required to install the dual battery isolator. Good instructions. I connected the dual battery isolator to an AGM power box in the passenger floor of my Sierra 1500. I wanted to be able to keep track of the dual battery isolator, so I attached a voltage meter to both the main and supplemental batteries. The wire gauge is correct, and everything is operating well. I’m delighted I purchased this stuff.

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