Generator Starter


Used to control the starting and stopping of generators used as backup for battery systems. Generator starts if the battery voltage gets too low, and shuts off when the battery is full.


  • Supports 2, 3 and 4 wire systems as well as advanced control systems
  • Low Cost/ High Reliability
  • Temperature compensated set points with adjustable temperature co-efficient, optional TC-2 temperature sensor required
  • Single unit 12 V to 48 V systems
  • Fully adjustable start and stop battery voltages
  • Time delay on start voltage so quick voltage dips won’t trigger the start sequence
  • Adjustable stop time delay, 6 minutes to 3 hours. Allows generator to run longer after reaching the high set point for proper battery absorption
  • Remote control capability
  • LEDs indicate generator starter status and relay position


This Genset starter monitors the battery voltage. When the battery voltage gets to its low set point, the unit starts the generator. When the battery gets to its high set point, the unit stops the generator.
The generator may be remotely started and stopped by dry contact closures, or by its local toggle switch start stop commands. The set points may be temperature compensated with an optional remote temperature sensor.

Sequence of operation on start up:

When the battery voltage is detected as too low per user adjustable set point the generator goes through its start sequence:

  1. The Generator start LED comes on.
  2. Precrank: 20 seconds relay closure (with LED on) prior to generator start/crank.
  3. Crank: relay closure (with LED on) for 10 seconds or until Genset start detected defined by three cylces of AC above 60 V.
  4. Run: Relay closure (with LED on) whenever generator is cranking or running.
  5. Load: load relay closure (with LED on) for 30 seconds after run relay closure.
  6. If the generator dose not start and the battery continues to drop, when the battery reaches approximately 0.25V below the low set point the generator starter will reset and go through the start up sequence. If this attempt fails and the battery continues to drop, at approximately 0.5V below the low set point the generator starter will reset and go through the start up sequence again. If this final attempt fails the fault relay will come on at 0.75V below the low set point to signal that there is something wrong with the generator.

Sequence of operation on shutdown:

When the battery has charged to the user adjustable set point, the generator goes through its stop sequence:

  1. Once the battery reaches the high set point a timer will start that will delay the shut down sequence for a user settable amount of time, minimum time being approximately six minutes and the maximum time being three hours.
  2. The Generator Stop LED comes on, start light turns off.
  3. Load: Load Relay opens (with LED off).
  4. Run: Run relay opens (with LED off) 20 seconds after load relay opens.
  5. Stop: Stop relay Closes (with LED on) for 10 seconds after run relay opens.

Electrical Specifications
Base Model: GS-1AC

  • Nominal battery voltages 12 – 48 V DC
  • Maximum Input (V) 63
  • Minimum Voltage 10
  • Relay: 8 amps @ 12/24 V , 2 amp @ 48 V , 5 amps @ 120 VAC
  • Self Consumption (A)
  • Relay Power 0.5W per relay coil when powered, voltage independent
  • Quiescent less than <20 mA
  • Fusing, 0.5 A resettable fuse, internal electronics only

User Controls

  • Generator Stop Set Voltage:
  • Generator Start Voltage:
  • Manual start/stop toggle switch overrides remote smart stop control (Toggling stop goes through stop time delay, to bypass delay short remote Stop terminal)
  • Remote start/stop

Potentiometers and test points read 1/10 the voltage you wish to start/stop
the generator. For example, if the generator is required to start at 23V,
set the start potentiometer for 2.3V.

LED indicators:

Generator start/stop
Relay position for precrank, crank, load, run, stop, fault

Mechanical Specifications


  • GS-1AC = 0.5 lb.
  • GS-2AC-1R = 7 lb.
  • GS-2AC-3R = 8 lb.


  • GS-1AC : 7” X 6” X 2” Open frame, mounted to aluminium plate.
  • GS2-AC-1R: 8″ X 8″ X 4″ NEMA 1R box, indoor rated
  • GS-2AC-3R: 10″ X 8″ X 4″ NEMA 3R box, outdoor rated


  • Euro-style Terminal Strip # 12 AWG

Operating Temperature: -40 to 60 deg. C
Humidity: 0 – 90% non-condensing,

Note: In the interest of continuous product improvement specifications
subject to change without notice.

Order Model No:

  • GS-1AC open frame for mount in user system
  • GS-2AC-1R NEMA 1R enclosure
  • GS-2AC-3R NEMA 3R enclosure