Eagle Eye Power Solutions

ELM-Series Battery Electrolyte Level Monitor

The ELM-Series Battery Electrolyte Level Monitor is a reliable dual sensor system that monitors the electrolyte level and temperature of individual flooded batteries. Utilizing low-cost, easy to install sensors, the system will alarm on low electrolyte level or higher than normal temperature. The sensors are simply and securely attached, either directly to the battery jar, or via an optional clip which allows the sensor to be removed and re-used if the cell should require replacement. The ELM-Series battery electrolyte level monitor and temperature sensor is customized to work for any flooded battery system. Each battery system includes an ELM-Monitor and single sensor per cell.

  • Low cost monitor for electrolyte level monitoring & temperature alarming
  • Alarm contacts for external alarming
  • LED lights on monitor and sensors for visual alarming on-site
  • Quick and easy installation, no glue or special adhesives required
  • Applicable to any flooded battery system regardless of voltage & amp-hour
  • Does not penetrate battery cell, can be installed while battery is in service
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Battery TypesCompatible with all transparent flooded battery types
Temperature Alarm Activation35 °C (95 °F), ± 2 °C (3.5 °F)
49 °C (120 °F), ± 2 °C (3.5 °F)
63 °C (145 °F), ± 2 °C (3.5 °F)
Optional: No temperature alarm
Level Accuracy±2 mm (± 0.08”) above or below line label
Input Voltage12 VDC, AC/DC wall adapter included standard
Additional voltage inputs available with optional PSU
Output RelaysSPDT volt-free contact relays for:
1+ low electrolyte level detection
4+ low electrolyte level detection
1+ high temperature detection
4+ high temperature detection
(L x W x D)
Monitor: 176 x 80 x 51 mm (6.9 x 1.6 x 3 in.)
Sensor: 54 x 35 x 15 mm (2.2 x 1.4 x 0.8 in.)
Sensor Cradle: 65 x 52 x 14 mm (2.6 x 2.1 x 0.6 in.)
Cables: 1.25mm pitch at length of 305 mm (12 in.)
WeightELM Monitor: 210g (7.41oz)


Product Literature

Technical Information


How does the ELM monitor temperature?
The electrolyte level monitor uses a high sensitivity temperature IC mounted in the case.

How does the ELM monitor battery electrolyte?

What cleaning is required on the battery cells before installing the ELM system?
Each ELM kit includes (1) roll of cleaning towels and (1) can of CRC PF Precision Cleaner. It is essential to clean the cells with the included cleaning kit to prevent the sensors from falling off the cells. One cleaning towel should be used to clean no more than (4) cells and one can of cleaning spray is good for up to 240 cells.

Is there an audible alarm available for the ELM?
The ELM does not include an audible alarm but it is possible to use an external one. The contacts on the warning outputs are completely isolated from each other and the sensor circuits, therefor you can drive any circuit with them, lights, audible alarms, motors, pumps etc. The contacts are rated at 15 amps for 125 VAC or 10 amps at 277 VAC. There is a rating of 2KV between the contacts and coil (the coil is connected to the sensor circuits).

How are the electrolyte level and temperature alarms reset?
An electrolyte level alarm occurs if low level electrolyte is detected for more than 40 minutes (to prevent spontaneous alarming). When a level alarm is active, it will remain so until the electrolyte level is restored and the R/S button is manually pressed on the sensor. The temperature alarm occurs as soon as the threshold temperature is detected, it will reset automatically after 4 minutes.

What are the guidelines for mounting the sensor?
The electrolyte level sensor must be mounted vertically in the upright position. It must be flat on the surface of the jar with the “level” line on the sensor in line with the “minimum” line on the jar.

What are the minimum clearances around the sensors on the battery?
The clearances are based on distance above and below the “minimum” line on the battery jar. The sensor frame can be removed to decrease the required clearances. Minimum height without frame: 29 mm (1 1/8th”) Typical height with frame: 35 mm (1 3/8th”) Minimum depth: 32 mm (1 1/4″).

What is the maximum cable length from the monitor to the sensors?
The longest length of cable from the monitor the sensor should not exceed 300ft (91 m). As always, a full loop should be connected from the monitor to the sensors and back to avoid voltage drop on the system.

Will the adhesive tape used to mount the sensor cause deterioration to the battery jar?
The adhesive tape included on the sensors and cradles has been thoroughly tested and will not damage the battery jar.

What is the power consumption of the ELM?
Power consumption depends on the number of sensors connected and the number of faults detected. The monitor consumes 0.36 watts; a single sensor consumes 0.024 watts with no faults. The total power consumption for common system configurations with no faults would be:

  • 60-cell system: 0.36W + (60 * 0.024) = 1.44W
  • 120-cell system: 0.36W + (120 * 0.024) = 2.88W
  • 240-cell system: 0.36W + (240 * 0.024) = 5.76W

The peak power consumption with 4+ Level & Temperature faults would increase the monitor to 1.44W:

  • 60-cell system: 1.44W + (60 * 0.024) = 2.88W max
  • 120-cell system: 1.44W + (120 * 0.024) = 4.32W max
  • 240-cell system: 1.44W + (240 * 0.024) = 7.2W max

What is the power requirement per sensor?
One Monitor and one sensor would require no more than 0.1 amps at 12 volts.

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