Connecting a Relay to the RPC Motion Sensor

To use our motion sensor to control motors, pumps or solenoids you need an additional "slave relay".

The more robust contact of this relay, which must be supplied from a separate suitably protected heavier circuit (see diagram), will then operate the larger load.

Never connect heavy loads to the sensor directly.

Because the slave relay coil is what is called an "inductive" device, a catch diode should be wired in parallel across the relay coil; and it must connect a certain way, or the fuse will blow first time you put it in.

Before you start, ensure that the battery voltage matches the sensor's and the relay's voltage. We sell both 12 Volt and 24 Volt motion sensors.

Catch Diode

  1. Connect (any) one of the sensor's red cables to the battery positive. Protect this connection with a 10 Amp fuse. Remove fuse for now. (Here's a nice weatherproof fuse holder, if you don't have one yet.)
  2. Connect one blue cable to the (now fused) red supply cable using a link (short bit of wire) that bridges the two screw terminals (inside the sensor).
  3. Connect the other blue cable to one of the relay switching coil terminals.
  4. Connect the other relay switching coil terminal to the battery negative.
  5. Connect the catch diode across the relay coil.
  6. Connect the battery negative to the sensor's other red cable.
  7. Place fuse back in holder. Now you should hear a click in the relay when motion is detected.
  8. Connect your load to the relay switch and battery (with appropriate fuse) as shown in diagram.

Download this article as PDF document.

We install solar systems in Northern NSW and Southern QLD.

Gold Coast (from Coolangatta to Southport), Nerang and Hinterland (Beaudesert) and out West (Warwick, Stanthorpe, Killarney)

Northern NSW (Tweed Heads to Yamba, including Evans Head, Byron Bay and Ballina); the Far North Coast Hinterland (Grafton via Lismore to Murwillumbah) and out West (Casino to Tenterfield, including Drake and Tabulam, as well as Woodenbong and Bonalbo)

For larger system we also go up to Brisbane or down to Coffs Harbour and even Glen Innes. Other places by arrangement.

We are Open for Business

Rainbow Power Company would like to assure our customers that we are trading (not quite as normal). System designers are working from home and can customise a quote for you (free of charge) over the phone and online. We are still dispatching and posting items, with safety precautions in place. You can still order online or over the phone, and pick up items from RPC (our show room is closed however, and appointments must be made to pick up orders). We are still doing site inspections, keeping the recommended social distancing.

Contact us

This is the perfect time to start thinking about your power needs for the future, reducing your bills, and safeguarding against future power outages, so call today and get in before the oncoming solar rush. PH: 02 6689 1430 or send an enquiry
..stay safe and healthy, your RPC family