Master Reminder

Ever forget your master switch on?  You are busy opening the doors for your passengers, giving the line personnel instructions, and before you know it, you have walked away with the master on and your battery dies.

Enter the Master Reminder.

This is an experimental product that you can install with many options.  In its usual installation, it includes a low voltage warning light and a beeper.

When the alternator ceases to produce power, the buss voltage will fall to the battery voltage which will be around 12.6volts.

When the buss voltage falls below approximately 13v, the low voltage light turns on.  After 1 minute the warning circuit turns on.  I have mine wired to a beeper.  When the beeper goes off, it reminds me to turn off the master.  Unlike a circuit that turns your master relay off (it still consumes current), this circuit does not introduce a failure point to a critical circuit.  In addition it trains the pilot to remember the master switch.


download Wiring diagram page 1    page 2

  • This circuit does not introduce a failure point in your critical master switch circuit.
  • the low voltage light flashes at a half second rate until the buss voltage rises above approximately 13V.  At that point the warning circuit is armed, and low volts light goes out.
  • When the warn circuit is armed, the low volts light turns on when buss voltage falls below 13V.  A 1 minute timer starts.
  • When 1 minute times out, the warn circuit is activated.  In the usual installation this actives a beeper reminding you to turn off the master switch.
  • A warning cancel switch can be wired in to cancel the warning for another 1 minute.
  • If the buss voltage rises above 13V, it cancels the warning and re-arms the low voltage monitor.
  • If a low voltage occurs in flight, the circuit breaker for this circuit can be pulled.
  • Includes assembled circuit board as shown, mating connector, mounting hardware, Piezoelectric beeper, and instructions.

Cost $46.95 plus shipping