Relay mount 100 Amp - suits all vehicles RM-100 | 12V or 24V

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Voltage: 12 Volt Vehicle
Sale price$71 Regular price$79


The Thumper Universal Relay Loom mount has been designed to suit all model vehicles, both new and old. This pre-wired relay mount is also compatible for vehicles that are using a DC charger (whether mounted on a battery box, in line or under bonnet).

The relay mount is a HEAVY DUTY isolator, designed to be fitted under bonnet. This is an ignition activated relay. The relay will act to provide power to the charging line it is feeding to when the vehicle is running, and will isolate from the starter battery once the vehicle's ignition has been switched OFF.

Pre-wired, this relay mount is the perfect option for your under bonnet dual battery system! Also available to purchase as a full kit on our website (TUR-L)


I have a DC Charger:

Why would I fit a ignition activated relay when I have a DC charger that acts as an isolator anyway?

Great question! The answer is:

Most DC Battery chargers will act as an isolator. An isolator will separate the charge line from the main starter battery once the voltage of the main battery falls below 12.7V (indicating the ignition has been switched off) - this is what we call 'voltage sensitive'.

DC chargers require approx 13.2 Volts at the vehicle's main start battery in order to 'engage' and begin to offer charge to the system. If the vehicle has a voltage in excess of 13.2-13.5 Volts, then the DC charger will operate perfectly, acting as the isolator, and no modification to the system will be required.

If however, the vehicle's voltage drops below 13.2 Volts when driving (as many new model vehicle's do), then many times, the DC charger will disconnected and will no longer offer charge to the system. If this is the case, then the only option is to 'over-ride' the voltage activation/disconnect component of the DC charger. This is easily done by connecting the 'over-ride' wire on your DC charger.

However, when you OVERRIDE the voltage on the DC charger, you also OVERRIDE the isolator component of the charger. This basically means that the DC charger will continue to drain from the main starter battery even once the vehicle's ignition has been switch off.

This is where the TUR-L will come into play.

Simply fit the relay mount and this system will act as your isolator to ensure that your main battery is protected and will not be drained at any stage after your ignition is OFF.


Included in this listing:

  • 1 x Relay Mount (Fitted with Relay / Midi Fuse Holder / MIDI Fuse)


Instructions for Fitting:

  • Fasten the Relay Mount under the vehicle bonnet as close to the main starter battery as possible (within 600mm) - see notes on the fitting the Relay Mount in the below diagram.
  • Using the lugs provided, connect a length of 6mm / 8mm or 13.5mm cable to the following:
    • The positive (RED) cable will connect to the remaining ring terminal on the Relay Mount (see image below)
    • The negative (BLACK) cable will connect either directly to the negative terminal of the starter battery, or, to the chassis bolt (a chassis bolt may not be fitted to all vehicles) - see notes in image above for more information.
  • Connect the positive cable from the Relay Mount (the RED cable with split conduit) directly to the positive terminal of the starter battery.
  • The remaining thin RED wire on the Relay Mount must connect to an ignition activated power source. An ignition activated source is a positive connection that is live ONLY with the vehicle engine running and holds NO power when the ignition is OFF.
    • For vehicles fitted with rain sensing wipers; it is recommended to use one of the Fuse-Taps provided to replace the fuse and connect this ignition wire.
    • For all other vehicles, an ignition activated source can be located either within the loom to the windscreen wiper motor, or by tapping into the back of a socket (such as a cigarette socket).
  • Final Step - Testing the charging system
    • Start the vehicle engine and increase the vehicle's RPM to approx 1500-2000 for 3 - 5 seconds. At this stage, allow for your vehicle to idle whilst checking the voltage on your charging line. The voltage should start to increase --> If the voltage increases at this point, then you have successfully installed the Relay mount.



- The aluminum bracket on the Relay Mount must be mounted to the vehicle’s body. Mounting to the body will provide an earth connection to the relay.

* If the relay mount is fastened to a plastic surface or to a fibreglass body, then an additional earth wire must be connected to the aluminum bracket via one of the mount holes provided.

The Relay Mount is equipped with two optional pre-drilled mount holes. Either hole may be used to fasten the Relay Mount; alternatively, the top foot may be removed, or straightened, to allow for mounting to the rear firewall or side guard of the vehicle.


The Relay Mount has been fitted with an ignition wire. This wire must be fitted to any positive connection that is ONLY live when the vehicle’s ignition is ON. The power feed must hold NO power when the
vehicle’s ignition is OFF.

For vehicles fitted with rain sensing wipers; it is recommended to use one of the Fuse-Taps provided to replace the fuse and connect this ignition wire.

For all other vehicles, the most common ignition source can be found within the windscreen wiper motor loom.


Example on how to install:

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