Posted by Kim Otte on Tue, Aug 03, 2010 @ 11:28 AM
The battery is the most vulnerable part of any uninterruptible power supply (UPS) system. The battery is ultimately at the heart of the UPS in terms of reliability. Understanding causes of UPS battery degradation, ways to prevent degradation and maintenance options are fundamental to ensure maximum system availability.
There are a few ways to extend the life of your data center UPS batteries and I'll talk about them here:
- Purchase the correct battery for your data center – There are many things that factor into the purchase of UPS batteries such as life expectancy, front or top access, voltage, capacity as well as other considerations. Be aware of these, for instance a VLRA (Valve Regulated Lead Acid) battery, while relatively low in cost, has low reliability. While a Flooded or Wet cell battery is much more expensive, it will give you the best reliability and a long service life.
- Is the battery manufacturer qualified by the major UPS manufacturers - Companies like Eaton/Powerware and Liebert/Emerson have qualified battery manufacturers they use for their UPS systems. These battery manufacturers include: C&D, Power Battery, GNB and Enersys.
- Is the battery fresh or surplus stock that has been sitting on a shelf - Batteries should not stay longer than six (6) months without recharging. Many times when you see a cheaper price it’s due to the need to move these off the shelf. It is difficult and labor intensive to charge pallets of them and if the batteries stay on the shelf too long they will need to be scrapped. Bottom line; make sure the da
te codes on the batteries are within six months from the date you received them. Otherwise you may be getting a five year product that is a year or more old.
- Install, manage and maintain batteries properly – Proper installation of the batteries is important and if not done correctly can lead to shortened battery life. These batteries are sensitive to room temperature, so a good maintenance practice is to keep them as close as possible to 77 degrees Fahrenheit. You need to make sure they are all kept as close to this temperature as possible so that some batteries don’t age faster than others, this can make the batteries die quicker.
- Make sure you have regular inspections of your batteries - the visual portion can unveil problems such as damaged or leaking post seals that can lead to corrosion or fires. Taking readings will tell you if one or more is not operating correctly due to a variety of reasons. A short within a cell will cause a lower float voltage on a battery. A battery with an open cell or low capacity may have a higher float voltage on it. The main problem is if one battery in a string that is wired in series (typical UPS application) starts to fail or fails it will affect the remaining batteries.
- Keep an eye on the battery's discharge status - if a battery isn’t recharged within 48 hours it can lead to damage.
Submitted by Paul Iodice, Power Electronics Supervisor - Electronic Environments Corporation
piodice@eecnet.com
Posted by Kim Otte on Mon, Mar 01, 2010 @ 01:50 PM
One of the topics we're frequently asked is "what are zinc whiskers?" This perplexing issue is extremely common and is found in data centers and computer rooms of all sizes.
The below post comes from Rich DeBlasi of SPEC-CLEAN (http://www.specclean.com/).
What are zinc whiskers?
Zinc whiskers are near-microscopic shavings that affect galvanized metal surfaces, usually the pedestals, stringers and th
e plenum side of floor panels. Though they can be caused by many factors, it's usually daily wear-and-tear (walking, moving equipment, removing tiles) that generates zinc whiskers. They are also quite small; all but the finest of HEPA filters aren't 100% successful in catching them.
What are the problems that zinc whiskers pose in my data center?
Although benign when undisturbed, zinc whiskers become a problem once they become airborne. They pose a threat to computers and other electrical systems in data centers. Zinc whiskers can be responsible for electrical shorts, impacting circuit impedance and can even cause disk failures, along with other catastrophes
What should I do if I suspect I have a zinc whisker problem?
Unlike some other situations, the longer the problem goes unchecked, the more extensive (and expensive) the solution is. Getting 
a lab analysis is a good start; however, hiring a data center cleaning specialist to assess the situation and make a recommendation that outlines the best method for remediating the problem is a mandatory step for any data center that is dealing with possible zinc whisker contamination.
Data center cleaning is something all facility managers need to think about. This type of service should only be performed by companies that are knowledgeable about data center environments. You don't want a traditional cleaning crew to bring in mops and soap that may cause damage to some of the infrastructure. It is recommended that a complete cleaning should happen at least once a year as part of your data center's preventive maintenance best practices.
Posted by Kim Otte on Mon, Oct 19, 2009 @ 02:44 PM
A power outage, however brief, can cause most data centers and businesses to grind to a halt. As a result, information, productivity and profit can be lost. Using an Uninterruptible Power Supply (UPS) is the easiest way to provide secure power to protect your mission critical systems. 
The UPS system protects against all types of power supply failures and disturbances. How does this work? By positioning the UPS system between incoming power supply and the load, when then the main power fails, the UPS system switches to the backup UPS batteries, ensuring an unbroken power supply is available to keep the critical load fully operational.
The need to properly size a UPS system is critical to its reliability and the systems need to be able to grow along with your data center. Data center managers need to make sure that in today's ever changing per-rack power demands - this is done correctly.
Recently Electronic Environments Corporation (EEC) Design/Build Manager, Jim Stark, offered his knowledge on the subject. I encourage you to check out the editorial at processor.com. You will find answers to questions such as:
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What are the main factors to consider when choosing the size of a UPS for a data center?
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What is important for readers to understand about VA ratings of UPSs?
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Are there different considerations for blade servers vs standard servers?
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And more...
Does anyone have additional recommendations for sizing a UPS system?