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Importance of Battery Monitoring in Standby Power InstallationsCost of Ownership Considerations
Technological advancements and business expectations have seen a tremendous requirement for providing
secure power sources especially over the last 10-15 years. It is no longer acceptable (not that it ever was
before) for any business or service to experience power outages due to inadequate maintenance and service
provisions. The consequences of power failures are simply too immense and can have a high impact on the
safe and profitable operation of any business.
Business sectors and industries effected by this requirement span across far too many areas to mention. It is
somehow accepted that, one would associate secure power requirements with Data Centres, ISP’s and
Financial Institutions, etc. There are of course many many other mission and business critical applications,
for example Power generation and switching, Continuous manufacturing processes, emergency services
and of course last but not least Telecommunication/Data Comm industry and the many forms it comes
under.
Business managers are required to ensure that equipment such as UPS’s are indeed maintained in a proper
manner in order to avoid costly down times. There are various surveys and other documents available,
which identify the cost associated with “down times” and the revenue loss to some businesses can be
measured in millions of pounds. There seems to be a greater awareness on the importance of implementing
a reliable battery monitoring & surveillance system which ultimately can bring massive savings to any
business.
In all such applications, the secure power is provided by means of an Uninterrptable Power Supply (UPS),
which will sustain supply of power to the critical load, in the event of a mains supply failure.
There are indeed many different considerations that need to be taken into account during the selection
process of the UPS unit. The purpose of this article is not to review the various products available and the
methodologies used within the product design to provide the output power. As a short note on this point
though, it is worth mentioning that there are indeed a number of different approaches available which
provide certain advantages and disadvantages dependent upon the application for which they are being
considered. The terminology “courses for courses” comes to mind whereby for many applications, a dual
conversion UPS may be the best solution available. The author will gladly provide further information on
this to any interested party upon request.
At the heart of every UPS system is a standby battery, which in many cases unless appropriate service and
maintenance regimes are taken into account, are the main cause of loss of supply to the load which the UPS
is meant to protect. In some cases, it only becomes evident that the battery is unable to sustain the supply to
the load, when there has been a failure in the incoming supply, by which time it is generally too late to
carry out any remedial work.
The message is, that looking after the battery is as important if not more important than the electronics
within the UPS itself. The ultimate requirement is to ensure that the battery will provide power to the load
in case of failure of the incoming mains. To this end, just accepting the fact that there is a standby battery
system installed is not sufficient and the integrity and the capability of the battery to support the load must
be examined and analysed on an on-going basis.
There are of course different ways of verifying the integrity of any battery system. These include carrying
out inspection and test programs at regular intervals. Dependent upon the frequency of these tests, one can
draw some conclusions on how good or bad the battery is. It is also very important to consider what type of
tests are carried out during each maintenance visit.
The main problem remains and that is, that the performance and characteristics of the battery, changes
continuously and simply expecting to find out about any degradation at the next visit may be too late. There
are many parameters including, temperature, float voltage, charging regime etc. that can effect the
performance of any battery. There are various types of batteries commonly used, and the focus of this
article is not to examine these in any detail. Over the last decade or so, there has been a tremendous
increase in the take up rate in the use of Valve Regulated Lead Acid (VRLA) batteries, which are
sometimes also referred to as “Sealed” and/or “Maintenance Free” which of course they are not. This
misunderstanding has lead to many system failures and accidents.
There is absolutely nothing wrong with regular manual inspection and tests carried out on any UPS and
battery systems. One will need to consider the frequency of tests, parameters measured and scope of work
carried out and finally the cost associated with these. To complement any maintenance regime, what is
needed is the means to monitor the performance of the battery on a 24/7 basis and report any adverse
conditions as they arise. This is the only way that true preventative maintenance can be achieved. This will
enable the maintenance managers to review the frequency of service visits in light of the additional
information presented by the battery monitoring system.
Battery Monitoring
The concept of battery monitoring is by no means new and for years, various manufacturers have marketed
products aimed at providing actual or predictive battery performance indicators. The technology and the
complexity of these vary between different equipment manufacturers but on the whole provided one is
aware of any limitations that may exist with any particular system, battery monitoring data can be
extremely important.
In recent years, with the technological advancements made in the electronics industry and the fact that cost
of electronic equipment have reduced drastically, it has been possible to provide battery monitoring
products at prices way below those initially offered only a few years ago.
Dependent upon the criticality of the application and the importance that is put upon the battery monitoring
requirement, various solutions can be considered. Traditionally, battery monitoring was nearly always
considered to be an expensive proposal when viewed in relation to mid range power UPS units of up to 120
KVA( dependent on the application of course). In realisation of this and the fact that “one solution will not
fit all” MGE UPS Systems are able to offer a number of products to cover the whole spectrum of
requirements across many industries. These products while maintaining the need for measurement and
monitoring of critical parameters of the battery and providing superb communication interfaces, are
designed to meet the imposing and tight Capital Expenditure budget constraints that all businesses work
within.
Causes of premature battery failure:
There are a number of reasons which can lead to a battery failure. These in turn are caused by a number of
other factors which will need to be addressed as part of the system design. Premature battery failure may
result from:
 Thermal runaway
 Positive plate growth
 Excessive water loss during recombination process
 Active material degradation
 Premature capacity loss
 Short circuit
 Corrosion
 Electrolyte loss
 Etc.
Important factors that can effect battery life:
Again there are a number of parameters that need to be controlled in order to make sure that the battery life
can be optimised. All batteries are designed to provide a specific “design life expectancy” in accordance to
conditions set out in National and International standards. Experience has shown that in many cases if
certain important factors are not taken into consideration, the performance and life expectancy of the
battery is greatly reduced. Some of these factors are:
 Float voltage
 Temperature
 Ripple current
 Application environment
 Charge current
 And so on
The graphs below illustrate the effect on life of a typical VRLA battery as a result of temperature and
charging voltage:
What parameters to measure
There are a number of battery monitoring systems providers available and each has preferred battery
parameters that it can monitor. On the whole the same basic parameters are measured in almost all cases. It
appears that dependent upon the parameters that any specific battery monitoring system can measure, then
that system is acknowledged as the “best “ in the market according to the relevant sales person. At MGE,
we fully understand that different applications may require varying levels of sophistication dependent upon
the criticality of the equipment and the environment in which they are used. To this end we are able to offer
alternative solutions which will meet the requirements of any application. The list below identifies some of
the features that were taken into account in devising the battery monitoring product offering by MGE UPS
Systems.
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Ability to measure individual cell/ block voltages, during charge and discharge cycle
Battery string voltage measurement
Current measurement during charge and discharge cycle
Pilot Cell temperature measurement
Ambient temperature measurement
Internal resistance testing of the battery
Individual string current measurement in multi-string systems
Readily identify defective batteries during normal operation and discharge tests
Modular and scalable in design to meet system expansion needs
Versatile and easy to install
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Discharge autonomy
Recharge time
User friendly – Provide customer definable parameters for alarms etc
Be able to interface with other equipment as part of the Building Management System (BMS)
Provide excellent local and remote communications interfaces on 24/7, 365 days per year basis
Provide comprehensive diagnostic reports to aid maintenance management
Meet the requirements of CE compliance
Provide a solution to the customer that will optimise their cost of ownership of the asset
The Solution
Having considered all the above points, and with some forty years experience in design and manufacture of
UPS and related equipment, MGE are proud to offer two unique product solutions which we believe meet
the requirements of any application. These products have been designed in close liasion with leading
hardware manufacturers in the industry to ensure that all aspects in terms of product specification ,
performance and physical orientation are taken into account. Both products provide monitoring and
analysis of all the critical parameters of the battery system and present the data in a number of easy to use
formats to meet the customer expectations.
The data can be presented in a number of ways including graphical and/or tabulated formats.
The main difference between the two products, is that the MGE Cellwatch product also provides
measurements of the internal resistance of the battery, while the MGE B1000 system does not. To this
end we are able to cover a wide spectrum of requirements in a variety of applications and within varying
budgets.
Communications Options
MGE battery monitoring systems can easily provide communication to a number of local or remote
locations via a number of industry standard protocols as illustrated below.
On Site
Modem (Dial Out Available)
Ethernet
System
Building Management
User Friendly
One of the most important features of any system is what is known as being “user friendly”. Both the
products have been designed with ultimate ease of use in mind. User definable parameters allow the system
to be configured to suit any specific requirements with minimal training. A comprehensive and concise
event log memory provides the means for the user to build a history of the performance of the battery
(various other system parameters are logged), and take preventative measures well in advance. The
concept of exceptional reporting has been employed which ensures that alarms are only raised if the system
parameters go outside the set limits. A number of alarm relay outputs are available and these can be
programmed in accordance to the specific site or application requirements. Alarms can also be prioritised,
which means the user can define the response level required in dealing with any situation.
Data Presentation
The information can be presented in a number of ways such as tabular or graphical formats. Each and every
battery cell / block within the system has a unique address which will make the process of identifying any
faulty block extremely easy.
Conclusion
Many businesses have at some stage suffered losses attributed to, by the failure of the UPS backup system
which should provide power to the critical load in case of a failure in the utility mains supply.
The consequences of such blunders in today’s business environment, simply can not be tolerated and have
given rise to an awareness to all business/maintenance managers to review their service and maintenance
policies/working practices.
At the heart of every UPS system, the standby function is provided by a battery. Regular preventative
maintenance visits are generally the way to conduct service and maintenance duties. As the performance
and integrity of any battery are indeed treated as dynamic characteristics and can change between yearly or
bi-annual maintenance visits, then the best method of providing full proof maintenance is to also install a
24/7, 365 days battery monitoring and surveillance system.
Having considered all the factors relating to, customer requirements in terms of performance and product
specifications, communications and protocols, cost of ownership etc. we believe that MGE UPS SYSTEMS
have the product and service solution that will meet all requirements. MGE CELLWATCH and the MGE
B1000 battery monitoring systems provide a number of unique features that will enable solutions to be
devised for any and all applications.
With some 40 years experience in design and manufacture of Uninterruptable Power Supplies and related
equipment, we pride ourselves in being able to provide engineering solutions second to none and would
welcome an opportunity to discuss your requirements with you.
About the Author
Mostafa Bandar has been in the power supply and UPS industry for some twenty years. Graduated with an
honours degree in Electrical and Electronics Engineering, spent many years of his career designing power
supply modules and systems. Over the last ten years with a focus on products and service sales, has
developed a great understanding aimed at providing solutions. Mostafa has worked for a number of power
companies in National and International markets. He is employed by MGE in capacity as UK Service Sales
Manager. He can be contacted by email on [email protected]
For more Information Contact
MGE UPS SYSTEMS LTD
www.mgeups.co.uk
www.mgeups.com
Tel : +44 (0) 208 930 3203