Dual Battery Management systems

6mm wire is the industry standard. 10mm is larger than battery cable! Remember it is the size of the copper core only! I power my van through 6 mm cable via an Anderson plug. The largest most goto is 8mm. Speak to an Auto Electrician or Solar Express, experts usually know best.

Have you considered simply running both batteries in parallel and installing a three way isolating switchinstead of expensive managing system".
You can set your fridge to cut out at a level that still allows you to start the vehicle,it is possible to run the batteries flat if you leave anything that doesnt have a low voltage cutout switched on eg headlights,radio,etc.
But nothing to go wrong,no electronics,not stressing the auxillary battery by frequent dischargingup to double the run time as both batteries connected at all times ,potentially longer battery lifejust something to consider...happy camping

Nomads,

TJM used to be authorised distributors for the Piranha Electronic Dual Battery management system.
Cannot see it on their Web site so they may have "dropped" it in favour of their "own" brand.

I can only recommend what I have experienced and the Piranha DBE150S or the higher featured DBE180S would still be my choice for a top line electronic Isolator.

TJM installed my system which included relocating the hydraulic reservoir and air conditioning pipes to fit the battery tray in.

One thing to look for. Do you want a standard "wet cell" deep cycle battery or an AGM style. You may have to source an AGM from another supplier if TJM don't have access to them, or you want a particular brand. Also, not many AGM style batteries will fit in the engine bay of some vehicles, they are just too big. Just keep this in mind.

I have a Navara and dual battery system wont fit, so I have gone for the Opposite Lock CM Dual Battery box. It has the chargemaster isolator, dual monitors ( Input Voltage & storage capacity) , Multiple power sockets, circuit breaker
and also a 7 metre lead . It can be taken away from the car and can fit any battery.
Website is Site Link

Hi Nomads,

I think that you have already had your questions answered by others, but I though that I would include my 2-cents worth.

The advice about wiring sizes was spot-on. Many people make the mistake of describing cable sizes in millimetres, whereas its the cross-sectional area of the conductors - expressed in square millimetres - which is relevant. 6 sq mm cable is also known as 8-guage cable. Elsewhere on this forum I have found references to the current-carrying capacity of different size cables, and from memory 8-guage cable is rated at about 70 amps. This would seem like plenty of capacity for the connecting cable of a dual battery system. As stated elsewhere, 8-guage cable when tinned fits snugly into a 50-amp Anderson Plug terminal.

With regard to an isolator, there are a number of good units on the market. I would recommend that you go with the TJM or Solar Express systems you have already identified for the sound reason that they are located close to you. I installed a dual battery system into my 80-series Landcruiser last year. I chose to use a solenoid-type isolator sourced from SuperCheap Auto. It cost $99 and came in an excellent kit complete with a generous length of 8-guage cable, an earth strap with crimped-on connectors at each end, 2 battery post connectors (for the new 2nd battery) and 4 solder-on cable end connectors. I thought that it was an excellent kit, and great value for money. 12 months later, the isolator continues to work really well.

Good luck with your installation.