Supplement: Power


Choosing the right battery chemistry for UPS systems


By Warren Venn, power specialist at Luso Electronic Products


A


n essential element of any uninterruptible power supply (UPS) system is the battery, however, the different chemistries available can


cloud end user choice.


As the UPS is designed to be always on to provide the reliable power source for critical systems, it’s therefore essential that the battery can provide a reliable power source and be easy to discharge and recharge effectively.


Major points to consider regarding the battery are safety, reliability and cost of ownership. The factors affecting all these are the different battery chemistries that are available, some of which are more suitable for different applications.


28 July/August 2025 Key technical comparison Metric


Energy density (Wh/kg) Cycle life (80% DoD) Round-trip efficiency


Depth of discharge (DoD) Maintenance Safety


Temperature tolerance Components in Electronics VRLA


~30-50 300-500 70-90% ~50%


Regular inspection H2


gas venting Moderate Li-ion 150-250


1,000-5,000+ 85-95% 80%+


Minimal, BMS managed


NiZn >50


~1,000-1,500 Likely >90% ~70% Low


BMS; risk varies by chemistry Non-flammable High for LFP; variable


Wide www.cieonline.co.uk


In this article we will discuss these different chemistries, their pros and cons and look at a newer technology that might be coming soon.


Standard UPS systems were originally built using valve-regulated lead-acid (VRLA). More recently Lithium-ion (Li-ion) has become prevalent especially for


systems where cost is not a driving factor or where the environment is harsh. We will discuss each of these and their pros and cons.


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