SC-40 Auxiliary Battery Charger


Discontinued (Legacy Information)

Price Discontinued
MPN: SC-40


SC40 & SC40-LR  Auxiliary Battery Charger

RRP was $100

The SC-40 was suitable for Defender and early Discovery models,
The SC40-LR was specifically designed to operate with the advanced electrical monitoring in Land Rover’s new Range Rover Sport and Discovery 3 and not cause incompatibility problems that other controllers can cause.

The SC40 was supplied in a Blister Pack


The SC40 was available in 12 or 24 volt versions. The SC40 was supplied with a 30 AMP Circuit Breaker, Crimp Terminals and mounting screws, Heavy Duty, 2 Way 8mm Plug, Socket and Terminals and Installation Instructions for fitting the Controller.

No additional relays or solenoids are needed to install and operate the SC40.

The SC40 can be operated in two different mode, the Main operating mode ( as supplied ) is to charge an auxiliary battery, the Accessories operating mode ( installer selected ) is to provide power for accessories from the auxiliary battery.

In both operating modes there are two primary objectives carried out by the SC40.

In the Main operating mode, the first and most important objective of the SC40, is to protect the vehicle’s main battery against being discharged bellow a point at which the battery would not be able to start the vehicle.

The second primary objective of the SC40 is that after the vehicle is started, the SC40 will make sure that the main battery has a sufficiently high enough charge in it before starting to charge the auxiliary battery. As the main battery ages, it will require more charging time to store enough charge to start the vehicle. The SC40 caters for this by not starting to charge the auxiliary battery until the voltage across the main battery is high enough.

Also, if the main battery fails during operation of the vehicle, when the motor is stopped and the voltage drops, the SC40 will isolate the two batteries from each other, thus preventing the auxiliary battery from being discharged by the faulty main battery. When it is time to start the vehicle, a set of jumper leads can be used between the auxiliary battery and the main battery to get the vehicle started.

In the Accessories operating mode, the most important objective of the SC40, is to protect the vehicle’s auxiliary battery against being discharged bellow a point at which the battery would damaged.


The Unique Operations of the SC40 make it ideal for weekend warriors.

Main operating mode. After turning the vehicle’s ignition off, most vehicle batteries are capable of supplying some of there stored power for other uses and still have enough charge left to be able to start the vehicle, the SC40, when used in the Main operating mode allows this additional power to be used thus giving your auxiliary battery up to 50% more operating time and this usually gives you around a day longer before you have to charge the auxiliary battery again This makes the SC40 ideal for all you Weekend Warriors.

So while there is extra power available at the main battery the SC40 shares the load between the main battery and the auxiliary battery and in doing this, the operating time for the accessories running off the auxiliary battery is extended but at the same time the SC40 will still automatically safe guard the main battery from over discharging.

Accessories operating mode. In this mode, the SC40 provides power from the auxiliary battery for accessories, like refrigerators, radios and lighting. As the auxiliary battery is not required to be used to start the vehicle, the auxiliary battery can be discharged to a much lower voltage then the main battery can be. At the same time both the auxiliary battery and the main battery must not be discharged to low as this will damage the battery and shorten the batteries operating life, the SC40 achieves all these operations, yet the SC40 is quick and easy to fit with an average installation taking about 45 minutes. Once installed, the operating of the SC40 can be monitored by checking the indicator LED on the front of the SC40.

When the LED is flashing, the SC40 is off and isolating the devises it is protecting and when the LED is glowing constantly, the SC40 is operating and has the devices connected together.




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