Hi Kyle,
Not sure on the amp rating of the altenator on your ute, but can offer some advice on the wiring/configuration of the battery system.
To keep the whole system reliable, the best way would be to purchase another Redarc SBI12. Anybody who deals with the Redarc brand will be able to order the isolator in from their supplier with re-programmed cutouts (e.g. 10.5V Disconnect / 11.5V Reconnect, or whatever you may want). This does cost a little bit more, but will be a whole lot more reliable, and will make use of your AUX1 battery (and may extend your stay for another day or two without having to start your vehicle).
You can also install a relay to the earth wire of the 2nd isolator, with the relay activation being triggered by the starter motor solenoid, meaning every time you start the car, the 3rd battery will be isolated, and will protect the cables/battery etc from being introduced to the starting system (cables being run to a third battery are normally thinner than the cables between the main and aux1), as the isolators' earth will be knocked out temporarily. Use the same "de-activation" method for winching, and you can use a pure deep cycle as your 3rd battery without causing damage from winching or starting...
Add in a toggle switch on the dash to the blue wire (override) on the second isolator (i recommend hooking up an led indicator to this also, so you have a visible indicator that the system is being overridden, and doesn't get left on when you don't want it to be), and you have complete control over your battery system. The only other thing that is often overlooked is a monitoring system, like a simple LCD gauge hooked up to a few momentary push-button switches, allowing you to check each battery individually.
I spec up systems like this quite often for customers, as I work in a 4wd accessory shop, and this sort of system achieves sophisticated results, using basic hardware such as relays and switches, which can be replaced at the Birdsville petrol station if required. The best part is that the system is ultra-reliable, and leaves almost all human error out of the equation - apart from the override toggle switch I mentioned, normally a momentary switch would be recommended to ensure it is disengaged when not required, but in this instance, we want the opposite.
Not sure on the amp rating of the altenator on your ute, but can offer some advice on the wiring/configuration of the battery system.
To keep the whole system reliable, the best way would be to purchase another Redarc SBI12. Anybody who deals with the Redarc brand will be able to order the isolator in from their supplier with re-programmed cutouts (e.g. 10.5V Disconnect / 11.5V Reconnect, or whatever you may want). This does cost a little bit more, but will be a whole lot more reliable, and will make use of your AUX1 battery (and may extend your stay for another day or two without having to start your vehicle).
You can also install a relay to the earth wire of the 2nd isolator, with the relay activation being triggered by the starter motor solenoid, meaning every time you start the car, the 3rd battery will be isolated, and will protect the cables/battery etc from being introduced to the starting system (cables being run to a third battery are normally thinner than the cables between the main and aux1), as the isolators' earth will be knocked out temporarily. Use the same "de-activation" method for winching, and you can use a pure deep cycle as your 3rd battery without causing damage from winching or starting...
Add in a toggle switch on the dash to the blue wire (override) on the second isolator (i recommend hooking up an led indicator to this also, so you have a visible indicator that the system is being overridden, and doesn't get left on when you don't want it to be), and you have complete control over your battery system. The only other thing that is often overlooked is a monitoring system, like a simple LCD gauge hooked up to a few momentary push-button switches, allowing you to check each battery individually.
I spec up systems like this quite often for customers, as I work in a 4wd accessory shop, and this sort of system achieves sophisticated results, using basic hardware such as relays and switches, which can be replaced at the Birdsville petrol station if required. The best part is that the system is ultra-reliable, and leaves almost all human error out of the equation - apart from the override toggle switch I mentioned, normally a momentary switch would be recommended to ensure it is disengaged when not required, but in this instance, we want the opposite.
