Thread: Dual Battery installation and management 2015 130 Dual Cab

I have no personal experience with that model battery management device, but on face value, you might find some issues if you intend to connect large loads to the aux battery. The user manual states that no winches or inverter >1000W should be connected to the aux battery.

IMO, the reason behind wanting / needing a DBS for touring or otherwise is to protect the starting battery from going flat- and leaving you stranded. My reasoning is that all critical (vehicle specific) loads are on the starting battery, and everything else (accessories) are on the aux battery, with the battery management 'cutting off' the starting battery from the accessory loads if/when the loads deplete both batteries to a point where it may endanger starting the engine.

The marketing of these kinds of devices use words like 'voltage sensing', 'bi-directional' etc, not sure where your chosen unit fits in with this, but might be best to have a 'helicopter view' of what you want your system to do before commiting to the components. Your need for a winch, inverter, or solar charging may make such a controller a poor choice. But by all means speak to the manufacturer or a auto electrician who does a lot of this work before you make the call (I am neither of these).

Nothing wrong with the Pirhana tray, I was considering this for my install, but needed to cram the other control gear into the battery box, so needed 2 batteries of the same BCI group 34 size.

I have traveled the country for 40+ years for work and pleasure with vehicles fitted with various multiple battery systems from a simple manual connection switch, big diodes to 'computer controllers'.
However since 2003 I've been driving a 130 with 3 batteries controlled simply by a 180amp relay (Hella). I have the main battery in the normal location beneath the passenger seat where the large relay is also located. In the corner of the rear tray on top of the wheel hump is mounted a ventilated steel box with two ~+100amp each deep cycles. The batteries are wired with large core starter cabling in heavy loom tubing for protection.
In normal operation the relay is activated to charge all three in parallel via the the engine power circuit. There is a dashboard switch in the relay coil circuit to manually stop the batteries being connected if desired; for example after an extended stay in one location when the auxiliary batteries have become run down and one doesn't want to connect them until the engine is running and the main battery has had a chance to recover from the engine start.
The 'computer controller' I had on a previous vehicle I threw in the bin as it had a 'power balancing' system that connected the main and auxiliary battery when the engine wasn't running to 'even out the charge', although I can't see what for. This was fine until my main battery had a cell fail with almost a dead short which promptly flattened all the batteries.
The simple solution is the best in my view, and I don't see any benefit in forking out lots of money when a relay and a switch do the job without any voltage drop.... just my two pennies worth.
.........peter