Under Bonnet Dual Battery Kit for Toyota Hilux / Fortuner

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 Hilux a proper second battery, charged intelligently while you drive, with the tray, bracket and wiring matched to your exact model.

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 handles both standard and smart variable-voltage alternators, and it carries 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 your Hilux variant and positions the charger for engine bay airflow. The powder-coated tray bolts to factory mount points, with no drilling and no modifications. Fuses, holders, cable, lugs, heat shrink and conduit are all in the box.

• 1KD-FTV 3.0L Turbo Diesel and 1GR-FE 4.0L V6 Petrol, 03/2005 to 09/2014
• 126 Series N80 2.8L Turbo Diesel Hilux and Fortuner, 10/2015 to 2025

The charger is the same in both. The tray and charger bracket are vehicle specific, so select the right option above.

This kit does not suit the new N90 Hilux, 48V mild hybrid models, or the 2.7L petrol. For the N90 we build a different system:
Custom Lithium 100Ah Toyota Hilux N90 Dual Battery, 2026 →

The battery is not included. We have tested and confirmed the batteries below fit this kit, because these are the ones we fit in our own workshop. Note they are the left-terminal versions to suit the Hilux tray.

Lead acid. The Century N70ZZLXHD MF Overlander 4x4/SUV, 760CCA, 100Ah → is our most-fitted option for cranking and general touring. The Century Dual Force+ 27LX 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. The SSB 12V 105Ah Dry Cell AGM Deep-Cycle → is a sealed dry cell that handles vibration and heat well in an engine bay.

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 BCDC1225D has a dedicated LiFePO4 profile, so it is a straight setup change.

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.