T4R5 Aux Battery Tray (Group 31)

Adding a second battery to a 5th Gen Toyota 4Runner is one of the smartest upgrades for overland, camping, and remote work setups. The hard part has always been finding a clean, strong spot to mount a real Group 31 battery without cutting up the engine bay or strapping it down with zip ties and hope. The T4R5 Aux Battery Tray (Group 31) solves that problem with a purpose-built mount designed specifically for the 5th Gen 4Runner platform, giving builders a proper home for their auxiliary battery and a foundation for serious dual battery wiring.

Why the T4R5 Aux Battery Tray Group 31 Setup Matters on a 4Runner Build

Most generic battery trays force you to drill new holes, fabricate spacers, or settle for a smaller battery that does not match your actual power needs. This tray is shaped and sized for the 5th Gen 4Runner engine bay, so it bolts in cleanly and holds a full-size Group 31 battery without the usual fitment headaches. For owners running rooftop tents, fridges, inverters, lighting kits, winches, and radios, that Group 31 capacity opens up real off-grid power capability instead of barely keeping up.

Built for Group 31 Battery Compatibility

Group 31 is the go-to size for serious aux battery setups because it offers high reserve capacity, strong starting power, and long deep cycle life when paired with the right battery chemistry. This tray is dimensioned to fit common Group 31 AGM and lithium options from brands like Odyssey, Northstar, X2 Power, and Battle Born, so you can pick the chemistry that matches your build budget and power demands. The tight fit also keeps the battery from shifting under trail vibration, which protects the terminals and the surrounding wiring.

Strong Steel Construction for Long-Term Use

A battery weighs a lot, and a Group 31 battery weighs even more, sometimes north of 70 pounds when fully built. This tray uses heavy-gauge steel construction to hold that weight safely over years of daily driving, off-road runs, and full load draws. The reinforced base and walls keep the battery planted no matter how rough the trail gets, which is exactly what you want when expensive electronics depend on a stable power source.

Powder Coated for Hawaii's Tough Environment

The tray is finished in a tough powder coat that resists corrosion from heat, moisture, and salt air. Engine bays are hot, humid, and full of acid vapor over time, and Hawaii adds island salt and rain into the mix. The powder coat protects the tray itself and helps prevent the kind of rust that quietly eats through cheaper aux battery setups after a couple of years.

Clean Engine Bay Layout for Easier Wiring

A proper tray does more than just hold a battery. It anchors the whole aux power layout, giving you a fixed reference point for running positive and negative cables, fuse blocks, isolators, and DC to DC chargers. With the battery locked into one known spot, your wiring stays organized, your connections stay clean, and future troubleshooting takes minutes instead of hours. That alone is worth the upgrade for anyone serious about a long-term overland build.

Bolt-on Install With No Major Modifications

The tray is designed to install using existing structure points in the 5th Gen 4Runner engine bay, so the install stays straightforward. No major cutting, no welding, and no permanent damage to the vehicle. The setup is reversible if you ever change your build direction or sell the rig, which protects resale value while still letting you build the truck the way you want today.

Product Specifications

What You Get

Best For: 5th Gen Toyota 4Runner owners building a dual battery setup who want a strong, well-fitted home for a Group 31 auxiliary battery to power overland gear, camping equipment, recovery electronics, and off-grid use.

For Hawaii 4Runner owners turning their rigs into real off-grid basecamps, the T4R5 Aux Battery Tray Group 31 setup gives the dual battery system the solid foundation it needs to actually work for years. IMM Hawaii Parts also handles dual battery installation, wiring, and accessory integration at our Maui shop, so you can plan the full power setup and roll out trail-ready in one visit.