Under Bonnet Dual Battery Kit for Toyota Prado 150 Series

Running a fridge, lights and a comms setup off your cranking battery is how you end up stranded at the far end of a track. This under bonnet kit gives the Prado 150 a proper second battery, charged intelligently while you drive, with the tray, bracket and wiring matched to your engine.

At the centre is the REDARC BCDC1225D, a 25A DC-DC charger that takes your alternator output and delivers a full multi-stage charge to the auxiliary battery, something a simple isolator or VSR cannot do. It accepts a 9 to 32V input and handles both standard and smart variable-voltage alternators, with charge profiles for LiFePO4 lithium, AGM, gel, calcium and standard lead acid.

An MPPT solar regulator is built into the charger, with REDARC Green Power Priority. When solar is available it draws from the panel first and eases off the alternator, saving fuel and taking load off the vehicle. Add a solar blanket later and it plugs straight in, there is no second regulator to buy.

The mounting side is what makes this a kit rather than a box of parts. The 304 stainless steel charger bracket is pre-drilled for the Prado 150 and positions the charger for engine bay airflow. The powder-coated tray takes an N70 case battery, and the whole assembly bolts to factory mount points, with no drilling and no vehicle modification. Six metres of 8 B&S twin core cable, midi fuses, holders, brackets, lugs, heat shrink and conduit are all in the box.

• 1KD-FTV 3.0L Turbo Diesel, 2010 to 2015, tray DBT0475
• 2.8L Turbo Diesel, 2015 onwards, tray DBT0476

The charger and bracket are the same in both, and either suits automatic or manual transmission. This kit does not suit Kakadu variants, as the engine bay is laid out differently.

The battery is not included. The tray is rated to a maximum battery of 300 x 174 x 220mm and 23kg. Some of the batteries below sit slightly outside that. We fit this kit in our own workshop and have tested and confirmed they do go in, which is why we still recommend them.

Lead acid. The Century N70ZZXHD MF Overlander 4x4/SUV, 760CCA, 100Ah → is our most-fitted option for cranking and general touring. The Century Dual Force+ 27X MF, 750CCA, 175RC, 90Ah → is dual purpose, which suits a second battery that also needs to crank.

AGM deep cycle. The Fullriver Deep Cycle AGM 105Ah → is built for repeated deep discharge, which is the pick if you are running a fridge for days at a time.

Lithium. The Invicta Xero 12V 120Ah LiFePO4 → is the only lithium we fit under a bonnet. An engine bay means sustained heat, vibration and dust, and not every lithium is built for it. It is around 10kg lighter than an AGM with far more usable capacity, 3000 plus cycles and Bluetooth monitoring.

The charger is solar-ready out of the box. To run a panel or blanket into it you will also need:

• 6mm twin core cable →
• SB50 Anderson plug →
• SB50 cover →
• Solar input bracket → Mounts the plug neatly in the engine bay.