Dual Battery Systems

Running a fridge or camping lights and even charging the camera via an inverter, all put a strain on your original battery. A dual battery management system is the answer. Here at TJM we offer a range of dual battery management and charging systems available for all types of requirements. If you want a cold drink and still be able to start the car in the morning then read on because this is for you.

Notes to consider when choosing Dual battery management systems,

Temperature compensating Alternators

Some post 2000 model vehicles have temperature compensating alternators. Mainly vehicles fitted with common rail diesel engines utilise this style of alternator. The temperature compensationg alternator will charge at approx 14V when the engine is cold, and decreases to 13.4V when the engine reaches operating temperature. For this reason, the alternator may only charge a dual or multi auxiliary battery system to 60-70% state of charge at best, depending on the battery chemistry type used.

Known vehicles with this style of alternator - Toyota Hilux, Prado, LC200 LC7679 D4D Common Rail Diesel. Petrol Kluger 2010 on and BF Falcon

Variable Voltage Alternators

Some vehicles released in late 2010 onwards with common rail diesel and petrol engines have variable voltage alternators that are on the vehicle CANBUS. These alternators vary output based on driving conditions at the time. The range of voltage can be between 12.3V and 15V For this reason, the alternator may not charge a dual or multi auxilary battery bank at all times, and may apply too high a voltage for the auxliary battery chemistry type at other times.

Known vehicles with this style of alternator - Nissan Navara D40, R51 Pathfinder 2011 onwards V6 Diesel only. Hyundai Santa Fe 2010 +, Range Rover 4 2011 +, Ford Ranger 2011 +, Pajero 2012 +, Mazda BT-50 2011 + and Land Rover Disco 4, Isuzu D-Max 2012.

our Brands


Dual battery charging systems, extra batteries, management systems and battery monitors.  Whether you’re planning to travel the outback or just want to keep the food cold in the 12 V fridge on a shopping trip, TJM have you equipped when it comes to battery backup charging. With the top of the range IBS System or DBS system, you’ll have the extra power to run a fridge, electric winch auxiliary lighting or even charging the camera battery. For the no fuss battery management system TJM Red Centa and Megatronics battery system will also keep everything charged.

Download Auxilliary Battery Brochure

intervolt dcc pro

Battery to battery charging technology has been around for some time now.  There are a number of products available that compare favourably, some good, some not so good.  Our goal from the outset was to design something better than the garden variety offerings so we created, what we believe to be the most inovative in-vehicle battery charging system to ever hit the market.

Download interVOLT DCC Pro Brochure

redarc - BCDC In vehicle Chargers

Redarc has over 30 years experience in the research, design, development and manufacture of a range of electronic voltage converters and associated products, inverters, power supplies, battery chargers, turbo timers, glow plug timers and trailer braking products. 


Baintech have a range of auxillary battery accessories that include the Power Top Battery Pack, Keepower and Ctek battery chargers. They also have an extensive range of quality sockets. 

Download Powertop product sheet  Download Keepower


Related Accessories

Generators, Chargers

* Please note suppliers may advertise prices that do not include freight and fitting.