DCDC Cable & Accessories

A DC to DC charger is only as good as the cable that feeds it. Heavy cable by the length, lugs, breakers, fuses and the leads that join them.

Rekcharge 25mm Battery Cable Lug with 10mm Hole

Regular price$2²⁵

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Rekcharge 16mm Battery Cable Lug with 10mm Hole

Regular price$1⁷⁵

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DCDC Cable & Accessories

Overview

DCDC Cable & Accessories Overview

About DCDC Cable & Accessories

A DC to DC charger is only as good as the run of cable that feeds it.

The charger sits somewhere between the starting battery and the auxiliary, often a few metres from either, and it pulls real current while it is charging, tapering as the battery fills and as the charger's own logic decides. Every metre of cable between the alternator and the charger costs voltage, and a charger that sees less voltage than it expects drops its output to match. The battery fills slowly and nobody knows why.

This collection is the run. Heavy twin core cable sold by the length, so the gauge matches the current and the distance. Lugs that fit the cable and the terminal, crimped rather than soldered so the joint survives vibration. Circuit breakers and fuses at the source end, because a chafed cable carrying alternator current is a fire, not a fault.

Then the connectors that join the pieces. Anderson leads for the runs that need to disconnect, extension leads for the runs that were a metre short, and fuse blocks for the installs with more than one circuit off the same battery.

Size the cable first, from the charger manual's own input and output cable recommendations and the length of each run. Input and output are often different, and one figure does not cover both. Everything else follows: a fuse rated to protect the cable, lugs sized to the cable, and connectors rated above what the charger will pull.

FAQs

DCDC Cable & Accessories FAQs

What size cable do I need for a 40A DC-DC charger?

For a 40A charger, 6 B&S (roughly 13.5mm²) is the standard cable size for runs up to five metres. This gauge is thick enough to handle the high current without significant voltage drop, which is critical for making sure the auxiliary battery reaches a true 100 percent state of charge.

If you are mounting the charger further away, such as in a camper trailer or at the rear of a long wagon, stepping up to 4 B&S (20mm²) is a smart move. Using cable that is too thin leads to heat buildup and a drop in charging efficiency, meaning your fridge might struggle or your batteries take much longer to recover after a night at camp.

Explore our heavy duty Battery Cable for custom lengths, or see our pre-sized Battery Wiring Kits for a simplified setup.

Where do I put the fuses for a DC-DC charger installation?

You must install a fuse at both ends of the main positive cable, as close to the battery terminals as possible. One fuse goes within 300mm of the starter battery, and another goes within 300mm of the auxiliary battery.

This setup protects the entire length of the cable from short circuits. Because power can come from both the alternator and the house battery, a fault in the middle could lead to an electrical fire if only one side is protected. Using the correct fuses provides a safety barrier for your wiring and your vehicle, especially when traveling over rough corrugated tracks.

Find the right protection in our Circuit Breakers & Fuses collection, or see your live charging status with our Battery Monitors.

MIDI fuse vs Maxi fuse for DC-DC chargers: Which is best?

MIDI fuses are better for DC DC chargers because they use a bolt down connection. This mechanical fix is superior to the push fit design of a Maxi fuse, especially when your vehicle faces constant vibration on corrugated outback tracks.

The bolt down terminals on a MIDI fuse holder create a low resistance connection that reduces heat and prevents voltage drop. This is a practical advantage for chargers that run at high amperage for several hours during a drive. While Maxi fuses are easy to swap, they can sometimes work loose or suffer from poor contact over time. Choosing a MIDI setup helps maintain a steady flow of power to your auxiliary battery.

Explore our full range of Circuit Breakers & Fuses to find the right protection, or see our compatible DCDC Chargers to match your hardware.

Should I use Anderson plugs or hard-wire my DC-DC charger accessories?

Hard-wiring is the preferred choice for permanent installations such as those inside a 4WD canopy or a caravan. A direct, fused connection reduces the risk of voltage drop and removes a potential point of failure that can occur with a plug that might vibrate loose on rough roads.

Anderson plugs are more practical if your setup needs to be portable or if you plan to move the charger between different vehicles. They allow for quick and easy disconnection but require regular checking to ensure the terminals stay clean and secure. For most fixed builds, a hard-wired setup provides the best stability and charging performance for your auxiliary power system.

Explore our range of accessories to find the right components for your build.