Remote - October 2011 - (Page 6)

Feature Article Powering Advanced AMR/AMI Networks When comparing LiSOCl2 bobbin cells, design engineers need to review key performance criteria such as voltage, capacity, size and weight, exAdvanced meter reading (AMR) and advanced metering infrastructure pected service life, temperature and environmental sensitivity, cost, the need (AMI) technologies have been commercially available since the 1980’s. to handle high current pulses and high discharge requirements. However, over the past decade, the pace of industry-wide adoption has Battery manufacturers often use nominal capacity to predict expected accelerated, with nearly half of all water meters in North America now operating life. However, this data can be very misleading, as the volume of equipped with AMR/AMI devices. active ingredients is limited by the size of the cell, so nominal capacity valAMR/AMI networks are gaining traction due to simple economics, as ues do not vary substantially. Other factors such as the inner structure of the water utility companies increasingly cell and the ratio of active ingredients view these upgrades as valuable can impact battery life. As a result, long-term investments. Utility mandesign engineers need to carefully gers base their investment decisions evaluate the Equivalent Operating on projected long-term benefits asCapacity (EOC) to properly calculate sociated with enhanced data capture, expected operating life, taking into improved customer service and account the self-discharge rate, greater operational efficiencies. The application current profile and enfinancial model has become more vironmental conditions. In long-life favorable due to extended battery life applications where current demand is and lower initial investment expense, low, higher EOCs are preferred. as the price of a typical AMR/ For example, a standard AA-size AMI network installation has come lithium cell with a nominal 2.4 Ah down, largely due to increased price capacity and 10µA self-discharge competition among major AMR/AMI rate, will lose about 1.75 Ah in 20 AMR/AMI device manufactures specify bobbin-type LiSOCl2 batteries because they offer the highest equipment manufacturers. years, or 73 percent of its initial caspecific energy and energy density of all existing battery chemistries. Whereas electric meters draw pacity, due to annual self-discharge. low voltage power from the grid, waBy contrast, a Tadiran XOL series ter meters are typically powered by lithium batteries, for reasons of cost and bobbin-type LiSOCL2 cell features a self-discharge rate of under 1 percent safety. Leading AMR/AMI device manufactures overwhelmingly specify per year, reducing operating capacity losses during long-term operation at bobbin-type LiSOCl2 batteries because they offer the highest specific energy low average current with moderate high-current pulses. In a typical applica(energy per unit weight) and energy density (energy per unit volume) of all tion, an AA-size 2.4 Ah XOL series LiSOCL2 cell will retain more initial existing battery chemistries. One reason for lithium’s high energy density capacity after 10 years than a larger A-size 3.2 Ah standard LiSOCL2 cell. is its large electric potential, which exceeds that of other metals, and which To properly evaluate battery manufacturer claims, engineers need to produces the high voltages typical of lithium batteries (2.7 to 3.9 VDC). perform thorough due diligence, demanding100 percent product traceLithium cells use a non-aqueous electrolyte, allowing certain lithium ability back to raw materials, customer references and fully documented batteries to operate in extreme temperatures (-55°C to 125°C). The widest test results for parameters such as battery pulse, low-temperature pulses, possible temperature range is an important consideration, as AMR meters discharge and repeatability. Performing a comprehensive vendor evaluation are typically located in remote, unheated places (underground pits or buildwill help ensure decades of maintenance-free performance. ing exteriors) that are subject to extreme environmental conditions. An entire AMI network can go down temporarily if frigid temperatures cause Hybrid Lithium Batteries Enable On Demand Two-Way RF widescale battery failure. Communications Bobbin cells are well suited for AMR/AMI applications that require high energy density, high voltage, very low self-discharge, and the widest possible temperature range. Standard LiSOCl2 bobbin cells consist of an outer cylinder made of lithium metal and an inner electrode that is reminiscent of a bobbin of thread, enabling the battery to hold more electrolyte than competing products. There is also a hybrid version, the PulsesPlus, for AMR meters that periodically require high current pulses. Bobbin-type cells were first introduced to the water utility market by Aclara (formerly Hexagram), which pioneered the manufacturing of wireless AMR meters back in 1984. Amazingly, millions of these early AMR meters are still in operation, the earliest of which are still running on their original batteries after 27 years in the field. The proven performance of LiSOCl2 batteries in earlier wireless AMR meter applications has given today’s AMR/AMI equipment manufactures the confidence to offer longer term performance contracts that enhance the potential ROI of AMR/AMI smart grid networks. The availability of a 20-year warranty greatly enhances the value of this long- investment, especially once you factor in the additional cost savings associated with the elimination of manual meter reading, enhanced customer service, faster and more accurate billing, improved leak detection and greater protection against tampering. 6 www.RemoteMagazine.com Sol Jacobs, Vice President and General Manager Tadiran Batteries Not All Bobbin Cells are Created Equal Bobbin Construction is the Preferred Choice Advances in technology have led to AMR/AMI networks becoming increasingly complex and feature-rich. For example, more advanced AMR water meters are now being designed to provide on-demand two-way RF communications. Two-way communications demand greater battery capacity to handle the high current pulses required for data gathering and transmission. To meet this power demand, Tadiran developed the PulsesPlus battery, which combines a standard bobbin-type LiSOCL2 battery and a hybrid layer capacitor (HLC). The standard bobbin cell supplies low background current when the device is in a sleep or ‘standby state, and the HLC stores and releases periodic high current pulses. Another feature of the PulsesPlus battery is a voltage curve that is distinguished by an identifiable plateau that occurs as battery capacity approaches full depletion. AMR devices can be programmed to interpret this voltage curve plateau as a warning that battery end-of-life is approaching, thus permitting automatic notification and preventative maintenance. The value of automatic end-of-life indication can be enormous. For example, the Water and Sewer Commission of Springfield, Mass. installed a network of 44,000 AMR meters, then after only a few years of operation determined it necessary to begin replacing 4,000 batteries annually, at an overall projected cost of $9.2 million. Concerned that their labor force could be potentially overwhelmed by a rapid, system-wide battery failure, the commissioners decided that it would be prudent to replace perfectly good batteries so as to avoid the potential chaos of having their entire meter http://www.RemoteMagazine.com

Table of Contents for the Digital Edition of Remote - October 2011

Remote - October/November 2011
KEMA Named a Seaport-Enhanced Prime Contractor for the US Navy
Opto 22 Releases iOS App for Automation and Control System
Powering Advanced AMR/AMI Networks
Smart, Connected Remote Sites
Minnesota D.O.T. Makes a Right Turn - To a Flexible Monitoring Solution
Reducing Industrial Energy Consumption: Monitoring is the Key
Shacking up in the Artic
AFCON Software and Electronics Released Pulse V1.50 with New Event Manager Add-On
Digi Launches New 3G iDigi Development Kit
Hikvision Launches 650 TVL CCD Day/Night Camera
VYCON Introduces Hybrid VDC XEB Energy Storage System
Crenlo Adds NEMA Wall-Mount Enclosures to Product Lineup
Industry News
Calendar of Events

Remote - October 2011