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Choosing the lithium battery with the longest possible service life increases the return on investment in advanced AMR/AMI technology.

Amr Ami Tadiran Trr 1308ww

Choosing the lithium battery with the longest possible service life increases the return on investment in advanced AMR/AMI technology

By Sol Jacobs, Tadiran Batteries

AMR/AMI technology is expanding rapidly, with nearly half of all North American water meters now equipped with AMR/AMI devices.

Amr Ami Tadiran Trr 1308ww
Tadiran's TRR Series battery delivers high capacity and high energy density without voltage or power delay.

The vast majority of battery-powered AMR/AMI water meters utilize bobbin-type lithium thionyl chloride (LiSOCL2) chemistry because it offers the highest specific energy (energy per unit weight) and energy density (energy per unit volume) of all existing battery chemistries. One reason for the high energy density is lithium's large electric potential, which exceeds that of other metals and produces the high voltages typical of lithium batteries (2.7-3.9 VDC). Lithium cells use a non-aqueous electrolyte that enables certain lithium batteries to operate in extreme temperatures (-55°C to 125°C).

Bobbin-type LiSOCl2 batteries have a proven track record in AMR/AMI applications, including batteries that were still operational after 28+ years in the field. Extended battery life is a direct result of very low annual self-discharge, which is affected by the chemical composition of the electrolyte and the design of the cathode.

However, not all LiSOCL2 batteries are created equal. For example, Tadiran bobbin-type LiSOCL2 cells feature an average annual self-discharge rate of 0.7 percent, whereas other brands using the exact same chemistry have a much higher rate of 2.5 to 3.0 percent per year. For AMR/AMI applications, it is critically important to choose the LiSOCL2 battery with the lowest possible annual self-discharge as longer battery life translates directly into a higher return on investment (ROI).

Powering Advanced Two-Way Communications

AMR/AMI networks are becoming increasingly complex and feature-rich, including advanced "On Demand" 2-way RF communications that require high-current pulses for gathering and transmitting data. To address this growing need, Tadiran developed the PulsesPlus™ battery, which combines a standard bobbin-type LiSOCL2 battery with a patented Hybrid Layer Capacitor. The standard bobbin-type cell delivers long-term power, while the HLC delivers the periodic high-current pulses required for data capture and transmission.

A unique feature of the PulsesPlus battery is that it allows systems to be programmed to provide a low battery status alert, including a 3.6V system that indicates when approximately 95 percent of the battery's capacity has been exhausted, and a 3.9V system that indicates when approximately 90 percent of available battery capacity has been used up.

The value of this low battery status alert can be enormous. For example, the Water and Sewer Commission of Springfield, Mass., installed a network of approximately 44,000 AMR meters. Then, after just a few years of operation, the utility determined it necessary to begin replacing 4,000 batteries annually at a projected cost of $9.2 million out of concern that its labor force would be potentially overwhelmed by a system-wide battery failure. The commissioners decided to replace perfectly good batteries in order to avoid the potential "chaos" of a large-scale battery failure. The use of PulsesPlus batteries may have eliminated the need for premature battery replacement.

Tadiran recently introduced another alternative for medium current pulse applications, the Tadiran Rapid Response TRR© Series battery, which delivers high capacity and high energy density without voltage or power delay.

When a standard LiSOCl2 battery is first subjected to load, voltage can drop temporarily and then return to its nominal value. TRR Series batteries virtually eliminate this voltage drop as well as voltage drop under pulse (or transient minimum voltage level). The final result is zero delay during the voltage response. These unique attributes enable TRR Series batteries to utilize available capacity more efficiently, thus extending the operating life of the battery by up to 15 percent under certain conditions, especially in extremely hot or cold temperatures.

Utility meter system designers need to stay abreast of changing battery technology to ensure that the optimum battery is being utilized. When evaluating batteries, system engineers should demand fully verifiable performance test data, customer lists and testimonials, as well as know that advanced manufacturing techniques are being employed to ensure consistent product quality, including Six Sigma and statistical process control (SPC) protocols.

If you would like to know which meter manufacturers use Tadiran batteries, contact sales@tadiranbat.com.

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

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