Battery Replacement in UPS Systems – Everything You Wanted to Know
Everything You Wanted to Know About UPS Batteries
Which of us UPS users hasn’t encountered the need to replace batteries in an expensive UPS system, only to discover a few years later that additional, and often significant, expenses are required to bring the device back to life? So, how do we make the right choice? This applies to all types and sizes of UPS systems available today. Let’s dive into the topic and cover different aspects related to battery replacement.
Battery Types:
The batteries used in UPS systems are mostly sealed lead-acid batteries. These batteries are often installed in rooms where people are present, and they are designed with one-way valves to release gas. Normal gas emissions are under 3%, but the presence of hydrogen gas, if released in high concentrations, can be toxic or even explosive, which necessitates the use of sealed batteries. Most batteries used in UPS systems operate at 12 volts, with a capacity ranging from 5 to 100 ampere-hours. In cases where large-scale backup is required (for systems of several hundred kVA), high-capacity wet batteries with individual 2-volt cells, capable of hundreds of ampere-hours, are typically used. These must be stored in a separate, ventilated room due to the large amounts of hydrogen gas they emit.
Lifespan:
Battery lifespan is determined by the manufacturer based on production process and type and is typically divided into two categories: 5-7 years and 10-12 years. However, in both cases, the actual warranty provided is usually between one and two years, depending on the manufacturer, distributor, and installation conditions. Optimal battery performance is maintained at an ambient temperature of 20-24°C. Higher temperatures will significantly reduce battery life. Additionally, the quality of the UPS charger and the charging pattern are critical; the same battery model can last one to two years longer in a device with a superior charger.
Discharge Cycles:
UPS batteries are typically designed for around 200 discharge cycles. After reaching this limit, the battery will degrade and may not provide the same backup time as it did initially. Some manufacturers offer batteries specifically adapted for frequent discharges, often using gel instead of acid, which increases their price.
Battery Weight:
The weight of a battery is directly related to its quality. For example, a high-quality 12V/7AH battery generally weighs around 2.3 to 2.5 kg, while a lower-quality battery, or one meant for security systems, will weigh less than 2 kg, indicating a lower lead content.
Lead Quality:
The quality and purity of the lead significantly impact the battery's ability to operate under different temperatures. Batteries with pure lead are suitable for operation in extreme temperatures, from below 0°C to above 40°C, making them ideal for special use cases.
Conclusion:
While I won’t endorse specific suppliers or models available in the market, there are several providers offering high-quality batteries at reasonable prices that are suitable for UPS use. Unlike electrical equipment that requires certification from the Standards Institute for import approval, any supplier can import batteries, leading to a wide variety of options. However, not all batteries on the market are suitable for UPS use. A UPS battery must support rapid, high-current discharge over a short period, and batteries intended for security or other applications may not be suitable, potentially resulting in malfunctions just when the UPS is needed most.
Therefore, it is strongly recommended not to be tempted by a low price, but rather to consult with a professional in the field and make an informed choice.
Written by: Huli Shamir
Service Manager – Advis Electronics Ltd.