Hey there! As a supplier of UPS Power Batteries, I often get asked about the terminal voltage of these batteries. So, I thought I'd take a moment to break it down for you in plain English.
First off, let's talk about what terminal voltage actually means. In simple terms, the terminal voltage of a battery is the voltage measured across its terminals when it's connected to a load. This is different from the battery's open - circuit voltage, which is the voltage when there's no load connected.
The terminal voltage of a UPS power battery can vary depending on a few key factors. One of the most important factors is the state of charge (SOC) of the battery. When a battery is fully charged, its terminal voltage is typically higher. As the battery discharges, the terminal voltage gradually drops.
For example, a common lead - acid UPS battery might have an open - circuit voltage of around 12.6 volts when fully charged. But when it's connected to a load and starts discharging, the terminal voltage will start to decrease. If the battery is deeply discharged, the terminal voltage can drop significantly.
Another factor that affects terminal voltage is the internal resistance of the battery. All batteries have some internal resistance. When current flows through the battery, a voltage drop occurs across this internal resistance. As a result, the terminal voltage is lower than the open - circuit voltage. The higher the internal resistance, the greater the voltage drop and the lower the terminal voltage under load.
Temperature also plays a role. Batteries generally have lower internal resistance at higher temperatures, which means the terminal voltage drop under load is less. Conversely, at low temperatures, the internal resistance increases, and the terminal voltage can drop more rapidly.
Let's take a look at different types of UPS power batteries and their typical terminal voltages.
Lead - Acid Batteries
Lead - acid batteries are widely used in UPS systems. A single lead - acid cell has a nominal voltage of 2 volts. Most UPS batteries are made up of multiple cells connected in series. For example, a 12 - volt lead - acid battery usually consists of six 2 - volt cells.
When a lead - acid battery is fully charged, the terminal voltage per cell can be around 2.1 to 2.2 volts. So, for a 12 - volt battery (six cells), the fully - charged terminal voltage can be around 12.6 to 13.2 volts. As the battery discharges, the terminal voltage per cell drops to around 1.75 to 1.8 volts. For a 12 - volt battery, this means the terminal voltage can drop to around 10.5 to 10.8 volts when it's almost fully discharged.
Lithium - Ion Batteries
Lithium - ion batteries are becoming more popular in UPS applications due to their high energy density and longer lifespan. A single lithium - ion cell has a nominal voltage of around 3.6 to 3.7 volts.
When fully charged, the terminal voltage per cell can be around 4.2 volts. For a UPS battery pack made up of multiple lithium - ion cells connected in series, the terminal voltage will be the sum of the voltages of individual cells. For example, a 24 - volt lithium - ion UPS battery pack might consist of six or seven cells.
As the lithium - ion battery discharges, the terminal voltage per cell drops. When it's almost fully discharged, the terminal voltage per cell can be around 2.5 to 3 volts.
Now, you might be wondering why knowing the terminal voltage is important. Well, it's crucial for several reasons.
For one, it helps in determining the state of charge of the battery. By measuring the terminal voltage, you can get an idea of how much charge is left in the battery. This is especially important in UPS systems, where you need to know if the battery can provide enough power during a power outage.
Secondly, monitoring the terminal voltage can help in detecting battery problems. If the terminal voltage is significantly lower or higher than expected, it could indicate issues such as a faulty cell, high internal resistance, or over - charging.
At our company, we offer a wide range of UPS power batteries. Whether you're looking for a Small UPS Battery for a home office setup or a Jump Starter Battery for emergency situations, we've got you covered. And of course, our UPS Power Battery selection is top - notch, designed to provide reliable power for your critical systems.
If you're in the market for UPS power batteries, we'd love to have a chat with you. We can help you choose the right battery based on your specific needs, whether it's for a small business or a large data center. Our team of experts can also provide you with detailed information about the terminal voltage and other technical aspects of our batteries.
So, don't hesitate to reach out to us if you have any questions or if you're ready to make a purchase. We're here to ensure you get the best UPS power battery solution for your requirements.
References
- Linden, D., & Reddy, T. B. (2002). Handbook of Batteries. McGraw - Hill.
- Bergveld, H. (2013). Battery Systems Engineering. Springer.
