How to Choose the Right UPS Battery for Your Data Centers?
UPS batteries in data centers play a crucial role in providing backup power in the event of a mains failure, ensuring the reliable and efficient operation of data centers. In the following, we will explore the various factors to consider when selecting the right UPS battery type for data centers.
First, let’s understand the working principle of an online UPS. When the mains power is normal, the voltage from the grid passes through a filter to remove high-frequency interference before entering the rectifier. The rectifier converts AC power into DC power, with a portion charging the UPS battery via the charger, and the rest feeding into the inverter. The inverter then converts DC power back into AC power for the load (such as servers, storage, and network peripherals). In the event of a mains power outage, the rectifier input is disconnected，the the UPS battery begins to discharge. The current passes through the inverter, converting it back into AC power for the load. Throughout this process, the load continues to operate normally without interruption due to the mains power failure.
The role of UPS batteries is to provide power to the load during power outages or faults and to provide sufficient time for the generator to start or the main power supply to recover. Although internal system capacitors can provide millisecond-level delay, it is obviously insufficient for power recovery or generator startup. However, when used in conjunction with UPS batteries, seamless power supply switching can be achieved.
Currently, the main types of UPS batteries on the market are lead-acid batteries and lithium batteries (lifepo4 batteries). Lead-acid batteries have been the mainstream battery in the UPS industry for decades, but with the rapid development of new energy in recent years, lithium battery technology has been rapidly improving and widely used in various fields, gradually replacing lead-acid batteries. Next, we will compare these two types of batteries from multiple aspects to better understand the differences between them.
Battery procurement cost: The main function of UPS batteries is to provide power during power outages or faults, and to provide time for the main power supply to recover. This is why large data centers typically install batteries that can run for 10-30 minutes, with generators being used subsequently to extend the runtime. Therefore, the procurement quantity is not necessarily large. Under the premise of meeting the requirements, the cost of lithium batteries is roughly twice that of similar lead-acid batteries. This is mainly because lithium battery technology is more complex and can meet more functional requirements.
Battery charging speed: Due to the more active chemical properties and higher energy density of lithium batteries, they have a faster charging speed compared to lead-acid batteries, approximately 8 times faster. Especially with lithium batteries using float charging technology, they can maintain the battery in a fully charged state, which is more suitable for fields with frequent power outages.
Battery size and weight: With the same capacity, the volume of lithium batteries is only 2/3 of that of lead-acid batteries, and the weight is only 1/3 of that of lead-acid batteries. Therefore, lithium batteries are smaller and lighter than lead-acid batteries, which may also result in lower subsequent transportation and installation costs.
Battery state monitoring: Regular testing of UPS batteries is essential to understand their status. For lead-acid batteries, regular inspection can observe whether the battery casing is swollen and whether there is white residue around the terminals to judge the battery’s condition. Lithium batteries are usually equipped with Battery Management Systems (BMS), which can monitor key parameters such as battery voltage, current, temperature, remaining capacity, and health status at any time, making the battery status clear at a glance.
Battery Lifespan: The cycle lifespan of lead-acid batteries ranges from 300 to 400 cycles. Lead-acid batteries are sensitive to temperature; as the temperature increases beyond a certain threshold, the internal resistance of lead-acid batteries also increases, thereby affecting their lifespan. On the other hand, lithium-ion batteries have a cycle lifespan of over 2000 cycles and a calendar lifespan of over 10 years, which is 4-5 times longer than that of lead-acid batteries. They operate within a temperature range of -20°C to 60°C and exhibit greater tolerance.
In summary, when choosing UPS battery types for data centers, it is necessary to consider factors such as procurement cost, charging speed, size and weight, battery state monitoring, and lifespan, and make choices based on actual needs and budget. Lead-acid batteries and lithium batteries each have their own advantages and suitable scenarios. If the budget is relatively limited and there are no high requirements for charging speed, lifespan, battery state monitoring, size, and weight, then lead-acid batteries may be a more economical choice. However, if the budget allows and faster charging speed, smaller size and weight, longer lifespan, as well as higher reliability and monitoring functions are required, then lithium batteries may be the better option.
Regardless, it is recommended to consult and evaluate further with our professional engineers before making a decision, to ensure the selection of the UPS battery type that suits your data center requirements.