Page 39 - EngineerIT March 2022

ELECTRONICS

UPS batteries are not simply batteries!

here is much more to batteries powering UPSs than what is generally understood. installations. At the present stage,
The batteries in a UPS ultimately determine its performance and longevity. To the current available range of lithium
Texplore some of the important factors when deciding on what type of battery to use batteries is not particularly suited
in a UPS, EngineerIT discussed this with managing director of PowerMan, Jonathan Palmer. for UPS applications due to price
The company has been involved in manufacturing, supplying and maintaining their and performance considerations.
own brand of UPS’s in South Africa for nearly 40 years. During the past eight and a half “There is however ongoing research
years the company has experienced exponential growth in turnover and has tripled its and development, and no doubt a
number of employees to over 30. This has necessitated the move a larger building. Palmer, suitable a lithium iron battery and UPS
who has been with the company from the outset in 1984, said that the move will give the combination will become available in
company much needed space for final assembly and testing. the near future. The main advantages of
The new facility allows PowerMan to set-up multiple battery packs ranging from a lithium iron battery would be its lower
2 (24VDC) to 40 (+240VDC/-240VDC) batteries in a set. The batteries are balanced into mass-to-power ratio and the number
an effective set before being installed into a UPS. PowerMan holds a stock of batteries of cycles that it can perform when
ranging from 12V7Ah through to 12V100Ah. From 40Ah up, the batteries are gel filled – compared to the AGM or GEL batteries.
this allows for a consistent performance in both higher and lower temperatures. “I believe that the key to our success
“One of the key components of any UPS are the batteries. Over the years we have and growth lies in our detailed approach
found that OEM manufacturers often have varying supplies of batteries, and while the to the manufacturing and testing
batteries all meet the same specification, the performance is not always the same. processes. The extra space will allow
Some time ago, our technical team decided that the best way to ensure consistency of us to have a much larger stock holding
the product was to ensure that the same batteries were used throughout the range. of UPS units, spares and batteries. Our
An extensive search was started for the right battery to meet the exacting standards of new premises will allow us to process
the PowerMan range. The search was narrowed down to four companies and sample approximately three times the number
batteries were imported and tested at our facility and in the field with selected clients. As of machines through our production
a result of these tests, PowerMan signed a distribution agreement with Sunstone Power, department on a monthly basis. Our
one of the leading battery manufacturers in China”, Palmer said. number of technicians on the road has
“The important thing about batteries is not just selecting the correct one but making more than doubled in the past two
sure that they will work as a set. As with any production item, the battery pack will only years, and we are set to continue that
be as good as its weakest link. While we already start the process with the best quality growth as we expand our client base”,
battery, our testing procedure will further eliminate any weak links before the completed Palmer said.
UPS leaves the factory.” The PowerMan UPS range
When building a bank of batteries, they are charged in parallel to ensure that all encompasses units from 650VA desktop
batteries in the set are at exactly the same starting voltage, and they are measured units through to 500KVA modular UPS’s. n
individually to conform. If a battery in the batch does not meet the voltage required, it is
cycled and recharged individually until it meets that requirement. If the required voltage is
not met, the battery is de-selected from the bank.
“One of the reasons for selecting Sunstone was to ensure consistent quality. Sunstone
only uses first generation lead in their batteries, not recycled lead. Although recycled lead
will work, it is not ideal for use in batteries designed for stand-by operations and in our
opinion, it is better suited to an automotive type of application”, Palmer said. We are so
confident in the quality of the batteries that we have increased the warranty on all our
UPS units to two years, including the batteries, and introduced a limited warranty on the
batteries for five years, where the users only pay for the time used. This means that if you
only get four years out of your batteries, on replacement of the batteries at PowerMan
you will be discounted for the year that you did not get.
The question is often asked why UPSs do not use lithium type batteries. Lithium
iron phosphate or LiFePo4 batteries are probably best when used in applications that
require multiple cycles and when charged and discharged on a daily basis; they are well
suited to an off-grid type of solution. However, the LiFePo4 batteries are considerably
more expensive than the traditional sealed lead acid AGM or GEL batteries which Commissioning two PowerMan 100KVA
UPS in parallel at Chris Hani Baragwanath
are designed for stand-by and back-up solutions and therefore better suited to UPS Academic Hospital

EngineerIT | March 2022 | 37