UPS Battery monitoring solutions rely on the continuous logging of battery related data to provide historical trend analysis and forecasts as to the future health and life expectancy of a battery. A suitably designed and installed monitoring system can help to identify early battery block failures and extend the working life of a complete battery set. This in turn can help to reduce operating costs and prevent unnecessary battery replacement, when there is sufficient capacity within the battery set to provide its critical power or renewable energy storage function. Typical applications for lead acid battery monitoring include uninterruptible power supplies but the same systems can be used to monitor batteries in other backup systems including emergency lighting systems, standby generators (starter batteries), energy storage systems, alarm, fire & security panels.
|Product||Battery Monitors||Individual Battery Blocks||Alerts||Predictive||Battery Block||Battery String||Environmental|
|PowerShield8||Yes – cabled||Yes||Yes||Yes||DC Voltage, Ripple Voltage, Ohmic, Temperature||DC Voltage, Current, Ripple Current||Ambient Temperature, Humidity|
|Enee.io eBMS||Yes – wireless||Yes||Yes||Yes||DC voltage, temperature||DC voltage, temperature||–|
|AKCP Plug-in Sensors||Requires a sensorProbeX+ base unit||Yes||Yes||–||DC voltage, temperature, current load||–||Additional plug-in sensors for temperature & humidity, and water leakage|
The battery monitoring products available from Server Room Environments include monitoring systems specifically designed and installed for battery sets (PowerShield8 and Enee eBMS) in critical power applications and plug-sensors for battery monitoring for use with more general environmental monitoring devices (AKCP) in server room and data centre environments.
Monitoring batteries on a regular basis can provide important data from which to determine charging issues or when a battery block or battery set should be replaced. Battery failures tend to follow a bath-tub curve. Early installation failures for lead acid batteries (VRLA, LA and stationary) and NiCd batteries are rare and may be caused by manufacturing defects or damage (shorts) during the installation process. End-of-working life failures are more common with data centre industry reports citing that that over 80% of uninterruptible power supply failures are due to battery issues. Whilst a battery may appear to be ‘health’, its capacity can decrease rapidly when placed under load as in the case of a mains power supply failure. UPS systems will generally test their batteries on a regular basis (every 24 hours), but the test is of a short duration and for the complete battery set rather than individual battery blocks.
Lead acid batteries tend to be of the 5 year or 10-year design life. This means that replacement should take place within years 3-4 and 7-8 according to battery manufacturer recommendations. Their design life is based not just on age but on the ambient temperature they are installed within (20-25⁰C is recommended) and the number of complete charge/discharge cycles (typically 300-400). In a temperature-controlled environment, with minimal usage, the working life of lead acid battery sets can be expected to beyond their predicted design life. Not only is this beneficial to the environment but also operational budgets (OPEX) which tend to cover replacement battery costs.
Lead acid UPS batteries can be tested using a hand-held battery tester as part of a UPS preventative maintenance visit. Sites either specify once or twice a year for a PM visit and in between this period (6-12 months). Whilst this is better than no individual battery block testing, it can miss fast deterioration in a battery block or set of cells which could lead to a DC voltage string collapse when placed under load. Collected data can also indicate issues with electrical equipment chargers that may not be alarmed and picked up by monitoring systems including BMS panels.
Most battery testing systems will monitor and measure a range of factors relating to the battery including DC voltage and temperature for each individual battery cells. Additional cell measurements include cell internal resistance (impedance) and ohmic measurement. Environmental monitoring may also be available including local room ambient temperature and humidity using additional sensors. The data collected allows for comparison between historical measurements and other installations for trend analysis.
In a UPS system the battery set is there to provide critical power coverage when a mains power supply failure occurs to automatically start-up a standby power generator or provide sufficient runtime for the IT servers to be safely shutdown. A UPS battery can fail instantly as can the automotive lead acid battery in the starter circuit of a standby generator. In emergency lighting and energy storage systems, using lead acid batteries, the same type of failure can occur. The only way to ensure the continuous healthy state of a battery set or individual battery is 24/7 monitor with data logging using a battery monitor.
24/7 battery monitors use battery data sensors connected to individual battery blocks. They collect battery and log battery data on a continuous basis for collection via hubs and collectors and analysis in product specific software packages and Apps. These are either available locally over an IP network, web-based portal or mobile network.
For more information on the right battery monitoring system for your installation and the battery installation & testing services available from Server Room Environments, please contact our Projects Team.