Supplement: Power Valve-regulated lead-acid (VRLA)


 Description: Sealed lead–acid, maintenance-free.


 Pros:  Low upfront cost  Mature known technology


 Cons:  Heavy and bulky  Limited cycle life (300–500 cycles)  Requires limited depth-of-discharge (DoD) to extend life


 Moderate efficiency (~70–90 per cent round-trip)


 Costs:  Cheapest upfront, but frequent replacements increase total cost of ownership


Lithium-ion (Li-ion)


 Description: Chemistry optimised for energy, safety, lifetime.


 Pros:  High energy density (150–250 Wh/kg vs 30–50 for VRLA)


 Deep DoD (80 per cent+), long cycle life (1,000–5,000+ cycles)


 High round-trip efficiency (85–95 per cent)  Compact, low maintenance, fast recharge long calendar life (10 – 15 years)


 Cons:  Higher upfront cost (1.75–2.3× VRLA for small UPS)


 Safety depends on chemistry and battery management system


 Extreme-temp performance considerations


 Costs:  Li-ion total cost of ownership becomes superior in around five years


 40 per cent lower over 10 years for single- phase UPS


Nickel–zinc (NiZn)


 Description: Emerging chemistry for UPS, especially data centres.


 Pros:  Higher energy/power density than VRLA  Non-flammable; wide operating temperature; long life (3× VRLA)


 Reduced footprint and cooling needs


 Cons:  Less common, limited availability; technology is still very new


Cost considerations & total cost of ownership  Upfront cost:  VRLA lowest  Li-ion (small UPS) 1.75–2.3× basic VRLA


 NiZn is still emerging, and initial costs are higher


 Total cost of ownership (over typical UPS life):  Li-ion is often around 2.8× cheaper per usable kWh; creating up to 40–50 per cent savings over 10 years


 VRLA costs are driven up by replacements taking into consideration labour and disposal costs


 Application


Basic PC/office backup


Best Chemistry VRLA


Data centres / edge computing Li-ion High-temp / harsh environments Li-ion


Reason Low cost, sufficient


High life, small size, reliability Better thermal tolerance


https://www.lusoelectronics.com/ Unlocking excellence with Watlow sensors


Precision in diverse applications Watlow sensors are renowned for their precision and versatility, offering solutions tailored to a broad spectrum of industries. From semiconductor processing to highly regulated heat treatment and pharmaceutical manufacturing, these sensors ensure accurate temperature monitoring and control, which is critical for maintaining product quality and operational efficiency.


Built for harsh environments Reliability in harsh environments is a cornerstone of Watlow’s sensor technology. These sensors are specially designed to perform under extreme conditions, such


as high temperatures, high vibrations, and exposure to corrosive substances. The robust construction of Watlow’s thermocouples and Resistance Temperature Detectors (RTDs) ensures durable and reliable performance in challenging environments such as aircraft and nuclear facilities. Features like precision manufacturing and the use of high-grade materials contribute to their longevity and accuracy even under the most strenuous conditions.


Versatile sensor solutions Watlow’s portfolio includes a variety of sensor types suitable for multiple applications:


Thermocouples: These are ideal for extreme temperature environments, offering fast response times and durable construction. They effectively serve industries such as semiconductor manufacturing and energy and environmental technologies.


RTDs: Known for their high accuracy and stability, RTDs are perfect for applications


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requiring precise temperature control, such as food processing and pharmaceutical processes.


Fibre optic sensors: Watlow fibre optic temperature probes are designed for high radio frequency environments. They are immune to the electrical noise typically found in plasma chambers, while offering industry- leading accuracy, precision, and reliability.


Ensuring accuracy and performance Each sensor undergoes rigorous testing and quality assurance measures to ensure it meets stringent performance standards. For instance, the mineral insulated thermocouples are configured to provide fast, accurate temperature readings in extreme conditions, making them indispensable across various high- temperature applications.


Advanced support and customization


Watlow goes beyond providing high-quality sensors by offering extensive support and customization options. Their advanced digital guide helps customers select the right sensor for their specific application needs, ensuring optimal performance.


Watlow’s commitment to innovation and quality ensures their sensors not only meet but exceed the demands of sophisticated industrial applications. With their robust design, precision, and adaptability, Watlow says that its sensors deliver unparalleled reliability and performance, even in the harshest environment.


Choose the right sensor for your application:


www.watlow.com Components in Electronics July/August 2025 29 Application suitability


 For small/office UPS: VRLA remains cost effective for infrequent or light-duty backup.


 For data centres, edge computing and remote facilities: Li-ion is ideal, it’s energy dense, compact, and low maintenance, with better total cost of ownership.


 Mission-critical/infrastructure: Li-ion is the best choice, offering temperature stability and long life.


In conclusion, when choosing a UPS battery chemistry, please consider initial cost versus lifecycle cost, size/weight constraints, maintenance demands, the operating environment, and desired reliability. In short, VRLA remains viable for low-cost, low-duty needs. Lithium-ion currently leads for long-life, high-density, mission-critical roles.


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