Radio/Appliance Timer SM95

GENERAL DESCRIPTION:
A 90 minute time-out timer for Automotive applications

• Stops the unwanted flattening of car batteries by 12V Radios, Inverters, Fridges etc.
• Two different modes of operation (A or B)….
  In ‘Mode A’ it activates your 12V appliance when you turn your ignition
  switch to the ‘Accessories’ position.
  In ‘Mode b’ it activates your 12V appliance when the engine is running.
• The appliance will automatically deactivate your 12V appliance 90 minutes after the ignition is turned off, or the engine is halted.
• A digital status display shows approximately how many minutes remain.
• A unique Start and Stop alert beep indicates timer activity.
• A ‘Fast Forward’ button is present to shorten the time delay.
• The Fast Forward button doubles as a manual On/Off/Hold control when operated from the standby condition.
• 10 Amp output contacts switch the appliance ON/OFF.
• Draws a low 3.6ma standby current from the vehicle battery.
• Simple installation.
• Reverse polarity protected.
• Microprocessor controlled.
• 100% Designed and Manufactured in Australia

SM95 Features In Detail
There are two separate modes of operation of the unit depending upon individual needs.
In Mode A will use the ‘Accessories’ position of the vehicle ignition switch as a trigger to wake up the timer from its ‘Standby’ condition (display blank).
In Mode b no wiring is made to the ignition switch. It will automatically activate when the engine is started. It does this by checking the battery voltage and reacts when it detects that the alternator is charging the battery.

If the timer was dormant (display blank) when the timer is triggered, a beep code will sound ( ). This is actually the letters CT in morse code. A few seconds later the output relay is activated. This small delay allows the vehicle to be started without the load of the radio or appliance being present.

When the accessories switch is ON, or the engine is running, the display will show an ‘A’ or ‘b’ to indicate the present mode and that the output relay is activated.

If in Mode A the vehicle ignition is turned to the OFF position, the display will change to a Digit ‘9’. This means that the countdown has commenced. It counts down in 10 minute blocks, so counting from ‘9’ down to ‘0’ will take 90 minutes.

During the countdown period this process can be accelerated by pressing the ‘Fast Forward’ button (below the display). While the button is pressed, the display counts down one digit per second until the ‘0’ is reached, whereby it returns to a Standby state.

If the ‘Fast Forward’ button is pressed for ½ second while the timer is in its ‘Standby’ state, it will act as a Manual Trip and wake up the timer regardless of the ‘Acc’ input or battery voltage.
If the button were pressed and held for two seconds from the standby condition, a special HOLD function is engaged. This will force the relay on indefinitely, and ignore all other inputs. During the HOLD condition, the letter ‘H’ appears on the display. Pressing the button once more for ½ second will return the unit to the Standby condition. This is a simple override to allow users to activate their appliance without having to trip or start the ignition system.

In Mode B the countdown is the same as Mode A, except that it detects that the engine has stopped by a fall in battery voltage. This will take between 10 seconds and 2 minutes, depending upon the amount of load across the battery at the time.

When the countdown first reaches ‘0’ the timer will sound a different beep code and then deactivate the power to the 12V appliance. ( ) This code represents the letters ‘AR’ in morse code.

While in the standby condition (display blank) the current drain by the unit is very low, approximately 3.5 milliamps. It would take about 3 to 4 months to flatten a 35 amp/hour battery if left unattended. In short, the power demand of the unit is very close to the ‘self discharge’ rate of a normal car battery, and has negligible effect on its state of charge.