Stop discarding perfectly good AMR meters

Long-life lithium batteries provide an end-of-life indication, allowing utilities to schedule meter replacement. By Sol Jacobs, Tadiran Batteries

Recently, I read article entitled “Good water meters are being replaced” which appeared in The Republican newspaper that describes out how the Water and Sewer Commission of Springfield Massachusetts is having to replace approximately 4,000 water meters a year, having installed over 44,000 of these meters a few years ago for $9.2 million.

Unable to change out all 44,000 utility meters at once, the Water and Sewer Commission instead initiated a multi-year change out program utilizing its own personnel, a move that seems wasteful to many, but not to the Commissioners, who see a systemwide battery change out as “potential chaos.” This problem could have been avoided had they installed long-life PulsesPlus™lithium batteries allowing for an “end-of-life” indication, which would have allowed the Commissioners to maximize battery service life and ensure continuous service with scheduled meter replacement.

Developed by Tadiran, PulsesPlus™ Lithium thionyl chloride batteries are typically used in applications where battery replacement or recharging is either impossible or extremely inconvenient, such as in water meter pits. This chemistry has been has employed by utilities for decades, most notably by Aclara (formally Hexagram) who currently has thousands of units in the field still operating on their original Tadiran lithium batteries after 23 years, with many more years of reliable service expected even under the harshest of conditions.

 PulsesPlus™ batteries combine a bobbin-type Li/SOCL 2 cell with a high rate, low impedance hybrid layer capacitor (HLC) that stores and releases energy, delivering high current pulses to power AMR meter transmitter units (MTUs). To make these devices last for decades on the original battery, they must be specially designed to conserve energy, with the MTU programmed to operate in multiple modes, including a sleep or standby mode, where power consumption is nil or at a low background current; a measurement or interrogation mode, which requires a few hundred milliamps of energy; and a transmission mode that requires high current pulses for a period of seconds or longer before returning to sleep or standby status.

PulsesPlus™ batteries deliver the widest operating temperature (-40 oC to 85 oC). They also feature an annual self-discharge of less than 1% per year, enabling them to provide over 20 years of maintenance-free service life without replacement.

In developing the PulsesPLus™ battery, engineers at Tadiran sought to differentiate these cells by integrating a predictable way to measure impending end-of-life. By contrast, typical lithium thionyl chloride cells operate at very stable voltage over their entire operating life, with no drop in voltage to indicate the battery state of charge, providing no evidence that the battery is losing its charge. Due to a lack of reliable data, perfectly good meters often need be replaced prematurely based on projections of remaining battery life.

 By contrast, PulsesPlus™ batteries offer the potential for end-of-life indication, coming in two distinct families:

• a 3.6v system with a 5% end-of-life indication when the battery has used  up 95% of its capacity
• a 3.9v system with a 10% end-of-life indication when the battery has used up 90% of its capacity

AMR meters equipped with PulsesPlus™ batteries can be programmed to interpret and communicate an end-of-life indication through the AMI network, providing utility managers with notification 1 to 2 years prior to battery end-of-life. This permits longer operating time between battery replacements, thus reducing long-term maintenance expenses and improving system reliability.

As a result, system-wide change outs that were previously scheduled approximately every 10 years (or less in the case of Springfield) can now be extended for up to 20 years or more without fear of system down time, disrupted billing, or reduced cash flow.

Had the Water and Sewer Commission of Springfield Massachusetts utilized PulsesPlus™ batteries, they would now have greater reassurance regarding the long-term reliability of their AMR/AMI network.

PulsesPlus™ batteries are available in sizes ranging from 1/2AA to DD and multi-cell packs. For more information or a list of AMR meter manufacturers who use Tadiran batteries, visit www.tadiranbat.com.

Sol Jacobs is Vice President & General Manager for Tadiran Batteries, Sol Jacobs has over 25 years of experience in developing solutions for powering remote devices. His educational background includes a BS in Engineering and an MBA.