Why Ohmic Metrics?
Outside-plant standby power supplies are generally acknowledged as the weak link in the reliability of the HFC portion of the network. Standby power supplies need batteries, which are expensive to buy, expensive to own, need periodic replacement, and their performance is generally hard to predict.
Previous generations of outside-plant power supply transponders allow network managers to perform rudimentary testing of their batteries by remotely commanding the power supply to run from batteries for a short time while the individual battery voltages are logged. This “intrusive” testing technique is dangerous, provides limited information about a battery’s ability to supply power for its full run-time, and provides virtually no information about where a battery is in it’s expected life-cycle. Clearly, a better way of remotely assessing battery health would lower maintenance costs while improving network reliability.
What are Ohmic Measurements?
A lead-acid (or any of its sealed varieties) can be characterized by an equivalent circuit consisting of a perfect voltage source and several resistances that make it non-ideal. Chief among these resistances is the composite “internal resistance” that limits the battery’s ability to deliver current. In recent years, the battery industry, as well as most power supply manufacturers and maintenance organizations, have realized the value of portable instruments that measure these ohmic properties. The measurements are done by injecting an AC test current into the battery and measuring the tiny resultant AC voltage variation this causes across the battery terminals. These measurement techniques are sometimes called “conductance”, or “impedance”, or “admittance”, but they’re basically a metric proportional to the battery’s internal resistance.[spacer size=”12″]
What can this do for me?
It is widely accepted that ohmic measurements are an accurate indicator of a battery’s amp-hour capacity, as well as a predictor of where the battery is in its life-cycle. By measuring and tracking these ohmic metrics, you can not only know the battery will produce the run-time you expect, but you can predict when the battery will need to be replaced because it is nearing the end of its useful life.
PowerAgent Transponders with Ohmic Measurements
Phoenix Broadband is a leader in remote battery monitoring systems employing ohmic metrics. Our PowerAgent BMS product line is in use in hundreds of mission-critical sites such as headends, central offices, cell-sites, data centers and anywhere else battery reliability is critical.
We have now merged our battery monitoring technology and our proven outside-plant transponder technology to offer a transponder solution that can be enhanced with individual battery ohmic measurement sensors. Click on the links at the top or bottom of this page to learn more about the technology, then contact a Phoenix Broadband representative to learn more about how ohmic metrics can relieve your battery maintenance burden