Dual Battery Systems

Dual Battery Systems are an essential part of many people’s set up as they give a dedicated power source for items such as fridges, lights, compressors and inverters without risking the starting battery. However, gone are the days of a simple solenoid system to isolate and charge the secondary battery. With the introduction of smart charging alternators, AGM and Lithium batteries and the addition of solar dual battery systems have become far more complex and require expert advice to get right. The TJM 4×4 Megastore team understand modern charging systems and can help guide you into getting the most out of your dual battery system.


Here at TJM 4×4 Megastores we work with you to understand your needs and your desired outcomes and work with you to develop a solution that will meet your expectations.

Product Description

Dual Battery Isolation Systems

There are a number of options when it comes to Isolators for your dual battery system. One key factor to selecting is the type of vehicle you have but also equally important is how you are going to use the system.


  • TJM 4×4 Equipped 20amp DC/DC
  • TJM 4×4 Equipped IBS
  • TJM 4×4 Equipped DCDC DBS
  • Redarc DCDC

Battery Options (Fixed Mount)

There are three main options when it comes to the battery you select for your dual battery system. These options are lead acid deep cycle (Good), AGM (Better) or Lithium (Best).

Lead acid deep cycle batteries are suitable for under bonnet or in an open tray or tub. They cannot be fitted inside a cab or canopy due to the gases that are discharged while the battery is being charged. These batteries are the cheapest option however are susceptible to reduced lifespan if not run through full discharge and recharge cycles on each use.

AGM batteries are the most popular option when fitting dual battery systems. They are suitable for under bonnet, in cab or canopy mount as they do not discharge any hazardous gases when being charged. AGM batteries are generally more durable for partial cycle use (part discharge then recharge).

Lithium batteries offer a number of significant advantages such as reduced weight and increased capacity over the other options. They cannot however be fitted under the bonnet of the vehicle due to heat restrictions. They are the most durable when it comes to partial cycle use.

Battery Box Options (Removable)

Spinifex Battery Box

The Spinifex Manufacturing Battery Box is designed to offer a durable battery housing solution for your battery and power distribution plugs. The unit is completely customisable to suit your needs. You start by selecting your battery then your sockets, voltage monitor and isolation unit – all of which are conveniently mounted into the Spinifex Manufacturing Battery Box.

The Spinifex Manufacturing Dual Battery Box truly is the box with the lot!

Baintech Power Top

Ready to go right off the shelf, this dynamic plug-and-play system features a 12V 100Ah gel battery and built-in three-way charging that makes operation smooth and easy. With charging inputs for AC, DC and solar, you’re free to charge anywhere, any time.

Since the Power Top is completely portable, it’s convenient to bring along and setup right at your campsite. That portability also comes in handy when you’ve got mates that may be keen to borrow this compact, complete power system. With the Power Top, you’re able to connect a range of different devices with different style plugs at the same time. It features a range of inputs for Ciga, Engel, USB and even the new Baintech LockOn socket for securing important loads over the roughest off-road tracks.


Solar panels a simple add on dual battery systems in vehicle that complement the existing charging arrangements. It can be hard to keep charge up to the secondary battery in your 4wd when you are running a fridge plus other accessories – the addition of a solar panel or panels compliments the charging from the vehicle and can help keep the batteries full charged. TJM 4×4 Megastore have a number of option to assist with your needs. From folding portable panels through to fixed mount solar panels TJM 4×4 Megastore have a solution to suit you.

Sockets and Accessories

TJM 4×4 Megastores can assist you in selecting the right sockets and plugs for all your accessory needs. From Ciga Sockets and Merit Plugs through screw in Engel Style connectors and Anderson Plugs we can assist.