Electrolyte Monitoring Sensor

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1 Inspirations FEBRUARY 2014 The Latest in Asset Protection and Condition Monitoring Electrolyte Monitoring Sensor The Inspired Systems Electrolyte Monitoring System is a breakthrough product that nonintrusively detects and reports changes in flooded cell electrolyte levels. The system consists of one to six electrolyte monitoring sensors which are affixed to the exterior wall of each monitored cell. Each sensor has two optical level detection transducers that can transmit an infrared light beam into the cell wall and measure the intensity of the reflected light. This intensity will change depending on the presence of electrolyte fluid on the other side of the cell wall. In This Issue Electrolyte Monitoring Sensor Non-Intrusive Battery Monitoring Float Current Monitoring System BM Mini Controller Future Development: Inspired Systems Testing Facility Two level transducers allow the sensor to detect three discrete fluid levels; Normal, Warning or Low. The electrolyte sensors are mounted to the cell wall with double-sided industrial foam tape (supplied pre-installed in the sensor). Installation is a simple matter of peeling off the tape, backing and affixing the sensor to the cell wall so that the top of the sensor is positioned at the normal fluid level. This mounting system is very strong, yet sensors can be removed if necessary. The adhesives used do not react with the battery housing or with the clear plastic shrink-wrap that covers the housing on some types. If more than one level sensor is to be used with a monoblock, the sensors are connected together in a daisy chain with the supplied interconnection cables. The first sensor in the daisy chain is then connected to the Inspired Systems battery monitoring sensor that monitors the monoblock. The electrolyte sensors are powered by the battery sensor over the interconnection daisy chain. Each electrolyte sensor has a bi-colour LED on its top surface. This LED serves multiple purposes during setup and operation. During normal operation, the electrolyte sensor is in a low-power sleep mode and the LED will be off. Every few seconds, the electrolyte sensors are awakened by the battery sensor in order to collect status information. While the electrolyte sensors are awake, the LED provides a local status indication; Green = Normal Red = Low Red/Green flickering indicates Warning. Features Electrolyte level monitoring for flooded cells Non-intrusive mounts on outside surface of cell Senses 3 discrete levels Works in conjunction with battery health sensor Alarm reporting via Battery Sensor and Site Control Unit Local LED indication Up to 6 electrolyte sensors per monitored monoblock Simple plug & play installation Small package (approx. 1.1 x2.1 ) Minimal space required; approx. 0.5 Lowest cost solution

2 Non-Intrusive Battery Monitoring Features Monitors float charge current for each of up to six strings Monitors up to 48 temperature points Generates alarms on any current measurement and any temperature measurement Uses intelligent algorithms to detect critical temperature problems, thermal runaway and battery aging Is non-intrusive No electrical connections to the battery plant Uses SNMP management interface Has programmable alarm contact outputs Accessed through a comprehensive web interface no software required Offers alarm signalling, internal data logging, Telnet remote configuration and much, much more Patent applied for technology 2 Inspired Systems is proud to announce a battery monitoring system that is a breakthrough in management of remote battery-based power systems. Based on 10 years of field experience, with over 300,000 batteries on over 75,000 sites, this system offers the combined advantages of performance prediction, easy installation and low cost. VRLA batteries are prone to a phenomenon called Thermal Runaway. If the battery is subjected to stresses that cause it to become abnormally warm, the charge current can rise dramatically. This triggers a regenerative electrochemical process that causes the battery to heat up even more. If left unattended, this process can ruin the battery, or worse, cause an acid leak or battery explosion. In addition, VRLA batteries draw more float charge current as they age naturally. This increase in float current can also trigger a thermal runaway. Inspired Systems technology continuously monitors the float charging current, ambient and battery temperatures. If any battery temperature rises above the ambient temperature and exceeds the user-defined thresholds, an alarm condition is generated, SNMP traps are sent and a contact closure on the control unit is activated. If any string s float charge current exceeds user-defined thresholds, an alarm is also signalled in a similar manner. The real power of the technology is in its intelligent correlation algorithms. There are three special alarms that are generated algorithmically. If, at any time any battery s ambient-referenced temperature exceeds a user-defined value AND the string s float current exceeds a user-defined value, a critical event alarm is generated. If the time since a recent discharge or recharge event is more than a user-defined interval AND any battery s ambientreferenced temperature exceeds a user-defined limit AND the float current has risen a user-defined amount from the user-defined baseline, a thermal runaway alarm is generated. If the time since a recent discharge or recharge event exceeds a user-defined interval AND the float current exceeds a user-defined value, BUT the temperature is below a user-defined value, a battery aging warning alarm is generated.

3 Float Current Monitoring System DESCRIPTION USAGE The Inspired System Float Current Monitoring System (FCS) is an accessory to the Battery Monitoring System. It consists of a current monitoring interface unit and a float current monitoring. The system accurately monitors changes in the DC charging current which are precursors of impending cell failure, as well as AC ripple currents which are indicators of charging system problems. The system also detects reversal of current direction indicative of a discharge condition, and provides an alarm indication if a discharge event occurs. The FCS current measurement probe is installed on a monitored current-carrying conductor. The conductor, which is typically either an interconnection cable or a bus-bar, is passed through the aperture of the current measurement probe. The probe is plugged into our CMI module. Multiple Inspired Systems current monitoring systems can be connected to the Site Control Unit s P-BUS via a daisychain using common CAT-5 jumpers. Power is supplied to the CMI module over the P-BUS. The CMI module has a usersettable address switch. This switch allows the user to assign one of 6 P-BUS addresses to the CMI. The CMI interface has LED s that indicate the status of the current sensor as well as communications with the Site Control Unit. Actual readings of the monitored currents, as well as user-definable alarm thresholds for minimum and maximum allowable current levels, can be viewed and modified via the Site Control Unit web interface. 3

4 Features Built-in SNMP proxy agent implements industry-standard MIB No special software licenses or expensive controllers required Built-in web server allows convenient read-only monitoring from any computer on the network Built-in SMTP mail client sends alarm messages to another computer addresses or to a mobile phone. Option for ultra-low cost solution by eliminating the sensors (monitoring battery voltages only) Fully downloadable operating firmware Provides power to external device (i.e. cable modem), eliminating extra power module BM Mini Controller The Inspired Systems BM Mini Controller is the first in a series of controller options designed to dramatically lower costs and provide battery health and cabinet/ hut facility monitoring capabilities. The BM Mini Controller can be equipped with either an eight battery wiring harness or a battery sensor option. The eight battery harness allows for the lowest cost solution monitoring, battery string and individual battery voltages. Using the battery sensor option provides additional battery measurements including ohmic measurements and individual battery temperatures. Both solutions offer facilities and cabinet monitoring capabilities. The control unit connects to a network switch, router or Cable/ DSL/Cellular modem via an Ethernet connection. Among the facilities parameters monitored are AC line voltage, equipment AC load current (option), moisture (option), controller internal temperature, two monitorable digital inputs and one controllable digital output. The Inspired Systems controller typically obtains its operating power from the battery string being monitored and supplies a 12VDC output to power a companion Cable/DSL/Cellular modem, thus eliminating the need for a separate modem power unit. 4 Inspired Systems has a built-in SNMP proxy, a built-in web server, and a built-in SMTP mail client. The SNMP proxy supports IEEE/ SCTE HMS MIBs making the unit compatible with virtually any management system. HMS traps are generated based on alarm conditions defined using the HMS property MIB. The built-in web server allows the status of the monitored batteries to be analysed from anywhere in the network using a common web browser. This eliminates the need for expensive client application software licenses. Near real time monitoring and alarm provisioning are available via standard web browser or software. The built-in SMTP mail client can be set up to send alarm messages to another computer (via addresses) or to a mobile phone when an alarm occurs.

5 Specifications Analogue Readings: AC input voltage; 0 to 140 VAC; true RMS Battery String Voltage; 0 to 60 VDC Individual battery voltage; up to 8 batteries Individual Battery Admittance (with sensor option) Individual Battery Temperature (with sensor option) Mini Controller internal temperature (tracks ambient) Control: User configurable intelligent battery balancing Digital Status: Two general purpose digital inputs Power: DC Input Power: VDC; 7 watts max (including modem) Modem Output Power 12 VDC nominal; 0.5A typ. Environmental: Temperature: -40 C to +80 C Humidity: 0% to 95%; non-condensing Optical Equipment: Eight battery harness AC current sensor Moisture sensor Programming adaptor 5

6 Future Development: Background The Inspired Systems Battery Management System (BMS) represents a breakthrough in battery monitoring technology. This multi-patented system uses advanced digital signal processing techniques to accurately and reproducibly measure the internal ohmic properties of stationary batteries. The system consists of a network of battery monitoring sensors (one for each battery in a power plant) and a solid-state site control unit (SCU) which communicates with the sensors and makes their measurements available to other management systems via industry-standard and open interfaces such as TCP/IP and SNMP. Each sensor is an intelligent unit that measures its battery s voltage, post temperature, and internal admittance (the inverse of impedance). Admittance measurements are made by injecting a digitally synthesized sinewave AC current into the battery and measuring the very small AC voltage which the test current produces due to the battery s internal resistance. Each sensor s activities are specified by the SCU, which polls the sensors frequently, telling them when to measure and collecting measurement results so that they can be compared to the SCU s user-defined alarm thresholds. A built-in web server displays the readings of all the sensors and allows complete provisioning without need for any proprietary software, and the SCU s SNMP monitoring interface allows any SNMP compliant software system to manage all the power plants within an enterprise. Battery Balancing: The Benefits Each of the batteries within a string of batteries is slightly different, even when they are brand new. These minor differences cause each of the batteries within a string to charge up to a different voltage than its peers. The charger unit, which is connected across the whole string, has no knowledge of what the state-of-charge of individual batteries is. Consequently, it has no way to affect their individual state-of charge. The more batteries that are charged in series, the harder it becomes to match them and maintain uniform charge levels. Therefore, there is a high probability that one or more batteries will remain undercharged or overcharged despite the fact that the string voltage is correct. It is widely accepted that batteries, when left in an overcharged or undercharged state for long periods of time, begin to sulphate, which leads to premature loss of capacity and early failure. Battery balancing systems are well known for their ability to extend the life of batteries in a short string. Traditional balancing units are devices which connect to a few batteries within a string, managing their state-ofcharge by removing charge from overcharged batteries and putting it into the undercharged batteries. These devices are usually only effective on short strings of 4 batteries or less, have little or no intelligence, and provide no remote monitoring information about how hard they re working to keep the string balanced. Intelligent Battery Balancing Intelligent battery balancing is a patent-applied-for by-product for intelligent digital sensor technology. The process takes advantage of each sensor s ability to produce a digitally programmable current in a battery while simultaneously monitoring the battery s voltage. Here s how it works: The site control unit (SCU) is the brains of the charge-balancing process. The SCU, by virtue of its knowledge of the terminal 6

7 voltage of each battery in the string, makes a determination that a battery-to-battery voltage difference exists which exceeds a user-defined threshold. If the battery balancing process is enabled (user controlled), then the SCU determines the highest battery voltage in the string, the lowest battery voltage in the string, and from this it computes the mean of the battery voltages within the string. Once the mean is determined, the SCU preloads all of the sensors within the string with information that the sensors will use to autonomously control a balancing process, until the SCU communicates with them again. Typically, the SCU speaks to each sensor every 2-20 seconds, depending on how many batteries the SCU is monitoring. Once the sensors are loaded with balancing information by the SCU, each sensor begins a process of measuring its battery s voltage, and if the voltage exceeds a target voltage specified by the SCU, it produces a small (typically a few tenths of an amp or less) digitally programmable balancing current in the battery. This small current causes the battery s terminal voltage to slowly decrease. All the while, the charger is putting its usual amount of charge current into the string, which causes the batteries that aren t being balanced to accept more of the available charge current. The next time all the sensors are polled, a new mean voltage is calculated, sensors on batteries that are below the mean are told to stop balancing, and sensors on batteries that are above the mean are told to remove charge from their associated battery. The net effect is that all the batteries within the string are quickly brought into a state of charge equilibrium according to the voltage that the charger is outputting. Once balancing has been achieved to within a user-defined range, conforming batteries are no longer balanced unless they go out of conformance. Numerous safeguards are built in to prevent undesirable loss of control: Each sensor is told when the balancing process is enabled and when it is disabled Each sensor makes a local decision when to stop balancing based on a voltage specification sent to it by the SCU. Each sensor contains a hardprogrammed deadman specification for the minimum battery voltage where balancing is allowed, no matter what the SCU says. Each sensor makes a local decision about the maximum time it can spend balancing its battery, based on a timer specification sent to it by the SCU. Each sensor has a hardprogrammed deadman timer which prevents it from balancing for too long, no matter what the SCU says. Each sensor generates a remotely programmable balancing current based on a specification sent to it by the SCU. Each sensor has a deadman current limit which prevents it from generating excessive balancing current, no matter what the SCU says. The SCU monitors and manages the balancing process, and so it knows how hard each sensor is working to keep its associated battery balanced. There are user defined alarm thresholds which can be specified so that the SCU will automatically send an SNMP alarm trap if any battery s charge is getting out of control. Intelligent Charging: Summary Intelligent battery balancing and charging is a revolutionary new concept in battery management, and it s built into the IS Battery Monitoring System. No other battery monitoring system has all the advanced features of IS, and no other system can extend battery life and monitor batteries. Call us today to learn more and to schedule a demonstration. 7

8 Inspired Systems Testing Facility The Inspired Systems test facility has been designed to test monitoring equipment for rail, mechanical and building equipment. It is currently being used to test Asset Protection, Non-Asset Protection and Communications to monitor and test equipment being used for various projects. The facility allows staff to carry out factory testing of various site equipment including PLC s, DED s, SFD s, and SCU s as well as other equipment. Not only does this speed up the amount of factory testing being done (of up to 10 sites) but it also allows Inspired Systems to carry out efficient fault finding. The test facility can test various alarms and alerts in conjunction with four charging sources and two power monitoring sources. When combined with Argus, real time indications are given for alerts and alarms. Testing that has been completed for current clients include air conditioner monitoring, mains power failure, door open, fire alarms, battery voltage, solar charging, stream Inspirations Newsletter We appreciate any feedback that you may have regarding our Inspirations newsletter. Our aim is to provide value to our readers and keep them up to date with the latest in Asset Management & Condition Monitoring. If you do not wish to receive this newsletter in the future, want to update your mailing details, or if you have any feedback for us please newsletters@inspiredsystems.com.au or call flow and stream depth monitoring. As it is a powerful facility, testing is not limited to these sources; testing is always completed as required by the client. Ph: Fax: Mordaunt Circuit, Canning Vale WA 6155 PO Box 1758, Canning Vale DC WA 6970 newsletters@inspiredsystems.com.au Copyright Inspired Systems. No portion of this newsletter may be reproduced without the written permission of the publisher. This newsletter is distributed with the understanding that the publisher is not engaged in rendering any legal or professional advice of any kind. The publisher disclaims any personal liability for the information, advice, recommendations and/or strategies presented within. It is up to the reader to comply with any local, state or federal laws. 8