True® Second Battery Kit For Car Truck RV Boat Automatic Isolator & Heavy-duty

(1 customer review)


True® 12V 140A  automatic 2nd battery kit for 4 wheel vehicle. Designed for heavy-duty performance, known for durability, waterproof cables, 360-degree heat resistance, anti-vibration casing, and easy to install kit.

SKU: DBK12LARGE2 Category:


Second Battery Kit Inclusion:

    • 1 (SBI) True Smart Battery Isolator complete with mounting screws
    • 20 feet #6 high flex red cable with tinned copper cable lugs
    • 3 feet #6 high flex black cable with tinned copper cable lugs
    • 2 positive brass & 1 negative brass alloy battery terminal ends
    • 3 loose crimp-on tinned copper cable lugs
    • 2 sections of adhesive lined shrink tube
    • 5 zip ties &  1 manual for installation
    • FREE Shipping for the US and Canada.
    • Delivery: USPS first class or priority mail
    • 1 Year Manufacturer’s Warranty
    • 1-day dispatch

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True® Truck & Car Secondary Battery Kit is Easy to Install

Years in research and innovation enable us to design a complete second battery install kit for any type of vehicle.  The long cable and anti-corrosion brass allows you to conveniently position the second battery isolator system kit inside the engine compartment.  Each kit has a wiring diagram and instruction manual which is also downloadable here.

(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.)

In this video, The customer installed the truck 2nd battery kit and an inverter

Truck Camper Shell Inverter Install and Dual Battery Setup
Truck Camper Shell Inverter Install and 2nd Battery Kit


The True® smart second battery isolator wiring kit is unique in that it is truly “smart.” When there is more power available beyond the required amount by the primary electrical system and its function, it knows exactly when to connect and detach to provide for the charge of the secondary battery.

True® Secondary Battery Wiring Kit Auto Detection 

The True® second car battery kit ability to operate in a dual battery management system for vehicles boils down to the unit reading the mind of the available charging source and using that power to charge your second battery for all those accessories while disconnecting and isolating the batteries from each other when too much energy is being used. True® car & boat second battery kit guarantees that your starting battery has enough energy to perform its primary function of starting the engine at all times.

Our Expert is You

Rather than trusting an engineer to design something that suits a conceptual setting, the people at True® have spent more than 8 years listening to the very users of these second battery kit  for car audio to truly determine what is needed in practical applications. The development and testing laboratory has been back roads, forests, mountains, deserts, sand dunes, jungles, rain forests, and wherever else you travel.

True® altered, modified, rebuilt, and most importantly, listened to the feedback gathered to create items that are “appropriate” for the application of the best car audio battery kit.

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Additional information



1 review for True® Second Battery Kit For Car Truck RV Boat Automatic Isolator & Heavy-duty

  1. jkru617

    I am using this on my 2020 F150 to put an extra battery in the bed. I had heard mixed reviews on if it would work with the type of alternator I have but it worked great. I ran a fridge off my battery in the back and it charged up every time I went somewhere with the truck. Truck battery stayed full too. Im an idiot with electricity but the instructions are straight forward.

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