Jim Mimlitz

Jim Mimlitz, SCADAmetrics

The Universal Duplexer is powered by a single, user-replaceable, made-in-the-USA, CR123A lithium cell. We presently power with either an Energizer(NYSE:ENR, St. Louis MO)-brand cell (EL123AP) or a Panasonic-brand cell.

The design of the Universal Duplexer is optimized for battery efficiency.  First, CMOS switching technology was leveraged to ensure that the idle-mode current draw is less than 1/100th of a microamp!

Also, during read-mode operation, the Duplexer utilizes charge pump technology to boost the supply voltage — ensuring that the device will continue to function even when the battery has a voltage sag due to age.

As a convenience, the Universal Duplexer features an integrated battery test button that illuminates an Indication LED when the battery is good.

In applications, it is anticipated that battery life will be affected by several factors, including secondary AMI/AMR device meter-reading frequency and by exposure to temperature extremes.  It is noteworthy that the battery life will not be affected by the meter-reading frequency of the primary AMI/AMR device.


Battery Stress Test

In order to gauge battery life expectancy, SCADAmetrics recently performed a battery stress test in which an AMI/AMR device was programmed to interrogate an encoder-type water meter, via the Universal Duplexer, at a high sampling rate of 15 reads per minute.

After 21 days of operation — approximately 453,600 meter reads — the Universal Duplexer’s battery finally reached depletion.

We were extremely pleased with this result!

Considering that the typical AMI/AMR endpoint meter-reading frequency is 4 meter-reads per hour maximum, that would equate to 12.9 years of meter readings.

Because our test took place within such a short period of time, we were unable to measure the effects of battery self-discharge

However, according to its specifications, the Energizer 123 Lithium cell features an extremely low self-discharge rate of 1% per year, when installed at a location whose temperature is 21C (70°F).  For every 10C (18°F) above that, the self-discharge increases by 1%.

Temperatures colder than 21C (70°F), on the other hand, will lessen the self-discharge rate; but they will increase the internal resistance of the battery, causing the voltage to sag when the secondary AMI/AMR device performs its read.  However, the Duplexer is designed to overcome such internal resistance effects with its integral charge pump mechanism.

When considering all factors, we are confident that under non-extreme temperatures and normal meter-reading sample rates, the Universal Duplexer will operate reliably for approximately 8 years before battery replacement is necessary. 


Important Note:  The primary AMI/AMR meter-reading device will always be able to read the water meter — even if the lithium battery is depleted or removed. This is an important performance feature that cannot be stressed enough!


Are you interested in how SCADAmetrics technology can help split a water meter AMI signal to two or more meter-reading systems?… Or do you have questions about its user-replaceable battery technology?  Give us a call! We’ll be glad to discuss the details!

Jim Mimlitz

About Jim Mimlitz

Licensed Professional Electrical Engineer @ SCADAmetrics. Specialties: Connecting Flow Meters with SCADA, Telemetry, and Building Automation Systems. Electronic Circuit Design, Software Development.

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