Why do we need to monitor on every battery cell/block?
Modern UPS systems have built-in monitoring capabilities designed to track overall battery performance. However, monitoring at the system level alone isn’t enough to ensure reliability or safety. Each individual battery cell plays a crucial role in the system’s performance — and a single weak cell can compromise the entire backup power supply.
The same concept applies to the built in monitoring in a UPS. If one would rely on a UPS system, that only measures the voltage between the positive and negative terminal of the whole battery(e.g., 300 individual cells), each cell should have an average voltage of 2.3 volts, with a permissible variation of +/- 0.1 volts, meaning the voltage can range from 2.2 to 2.4 volts. The total voltage of the entire battery setup is allowed to fluctuate by +/- 30 volts, so the small impact of the reading of a faulty cell will not be noticable. This variation in individual cell voltages is not detectable in the overall reading. Therefore, small voltage discrepancies in individual cells may not significantly affect the total voltage reading because the total voltage can still differ by that amount, masking the individual variations.
Batscan measures 6 cells at a time
Because of the way batteries are built, we cannot measure each battery cell individually. We can only measure across six cells at a time—just as a traditional UPS typically measures the total voltage across all 300 cells at a time. When monitoring battery cells, we measure the total voltage across a group of cells. If each cell is allowed to vary slightly, small deviations in individual cells may not be noticeable when looking at the total voltage. A small change in one cell’s voltage might not trigger an alarm if the variation is within a normal range for the entire group. To ensure that Batscan can detect real issues, we increase the threshold for detection. Instead of triggering an alarm for a small voltage change like 0.1 V, we require a larger deviation—0.6 V—across the group of cells. This ensures that only significant issues, affecting multiple cells, will trigger an alarm, helping to avoid false alarms and ensure the system’s reliability. The remaining question is whether it's possible to detect a fault in a single cell when we're only measuring six cells at once.
The Role of Batscan Battery Monitoring System
The key to avoiding costly replacements and ensuring maximum reliability and safety is having a monitoring system that has no means off affecting the batteries in any way. Batscan is a solution that enable real-time monitoring at the cell/block level, tracking key parameters such as voltage, current, and temperature for each battery in the system. This level of precision allows you to identify any early signs of failure before they affect the entire UPS. By detecting weak cells early, maintenance can be performed proactively, preventing costly disruptions and extending the life of the whole system.
Not all batteries in a UPS (Uninterruptible Power Supply) system fail simultaneously. Typically, it’s one battery that starts to degrade first, while the remaining batteries continue to perform normally. However, when one battery fails, it impacts the entire string of batteries. Since the batteries in a string work together to maintain the correct voltage and capacity, the failure of just one can cause an imbalance, which may result in the entire UPS system failing.
Why Replacing the Entire Battery System Isn’t the Answer
It’s a common misconception that when a battery in a UPS fails, the entire battery system needs to be replaced. In reality, if the batteries are relatively new and the failure is isolated to one or a few cells, there’s no need to replace the entire UPS or battery pack. With effective monitoring and regular maintenance, it’s more cost-effective and efficient to replace only the faulty battery or cells, rather than undertaking a full system replacement.
Why Overdimensioning Isn’t the Answer
Some might suggest overdimensioning the UPS system with extra battery strings to create redundancy in case one string fails. While this may seem like a reliable solution, it comes at a high cost — both financially and environmentally — without guaranteeing true reliability.
Adding extra strings without a proper monitoring system misses the point. Without visibility into where faults occur — and where new ones might appear over time — you’re left with higher upfront costs, increased maintenance, and no real improvement in system reliability. More importantly, it’s not a sustainable long-term solution.
Focus on Sustainability and Cost-Efficiency
The most efficient and sustainable approach is to focus on regular monitoring and maintenance rather than overdimensioning. With accurate battery health tracking, you can address the issue at its source — replacing only the defective batteries. This not only reduces the risk of complete system failure but also prevents unnecessary costs associated with replacing entire UPS systems or adding redundant components.
By utilizing advanced battery monitoring solutions like Batscan, you can enhance the reliability of your UPS system, minimize costly disruptions, and safeguard critical operations. Advanced battery monitoring ensures the optimal performance and longevity of your UPS, eliminating the need for costly and unnecessary overdimensioning.
Learn more about why replacing all the batteries is neither efficient nor effective on the Battery Reliability page.
