Battery Discharge Alarm

All our products are proudly made in the United States of America.

H2 Hydrogen Gas Vent

On-battery" alarm protects sealed and flooded lead-acid batteries from over-discharge.

A battery discharge and temperature alarm version using a thermocouple inserted between the cells to protect also against over-temperature is available to OEM customers

  Installation & Operation Instructions


  • Alarm reference voltage tailored to the battery.
  • Prevents over-discharge, especially damaging to sealed batteries.
  • Supplements or replaces battery discharge indicator on vehicle.


  • Mounts on the battery.
  • Easy installation.
  • 80-db alarm.
  • Intermittent sound when battery needs to be recharged.
  • Potted to protect against sulfuric acid.
  • Alarm reference voltage fixed, not adjustable.


  • DIMENSIONS (L x W x H)
    4" x 1-5/8" x 1"
    Magnetic back adheres to battery steel. Use plastic ties to attach to an inter-cell connector.
    Three year limited warranty—excludes water and sulfuric acid damage.
    3 wires -- one to battery +, one to battery -, one to 12VDC.
    4th. wire optional -- attach to an external horn for a noisy environment.
  • Alarm Reference Voltage Setting
    Sealed battery 1.99 volts per cell.
    Flooded battery 1.85 volts per cell or as specified by customer at time of order.