Detailed Analysis of Commercial Battery Storage Systems with Analysis Pro

Batteries are taking on an increasingly important role in decentralized energy systems and constitute the heart of off-grid systems. They can also be increasingly found in on-grid systems, where they can cut energy purchase costs by means of increased self-consumption or peak load shaving. Battery monitoring plays a key role here. After all, PV system operators want to know whether their systems are actually working as intended, because downtime costs money and causes hassle. That is why SMA is offering a comprehensive upgrade for battery analysis via ennexOS.

Battery monitoring across three levels

With ennexOS, the battery system can be monitored across three “levels.”

1. First, at the system level, you have the system energy balance. This provides users with an overview of all energy flows on the generation and consumption sides. The colored areas on the diagram are bordered by total generation and consumption in grey. The colors show where the energy has come from and where it has gone (Figure 1).

Figure 1: System energy balance

2. Under “Energy and power – battery”, the device level shows the key data for the battery system at a glance. The battery display familiar from the system dashboard can be found in the top left. This shows the state of charge and system power. One handy feature is the time stamp above the battery icon, which changes depending on the SOC. It shows how recent the displayed values are (Figure 2). Our measured values were transmitted four minutes ago. Everything’s fine.

PV system operators can also use the chart to view past battery usage and how the state of charge has changed over the previous hours, days, weeks or months.

Figure 2: “Energy and power – battery”

3. Many customers, particularly those operating on a commercial scale, use multiple battery inverters, e.g., in the Sunny Island Multicluster format (Figure 3). For these systems, just as for PV inverters, Sunny Portal powered by ennexOS offers a range of visualization options at the device and system levels. For the first time, the energy and power values can be displayed in Sunny Portal at the system level alongside the existing data at the inverter level. The state of charge thus constitutes a mean value for all batteries in the system – weighted by their true capacity, of course.

Figure 3: Sunny Island Multicluster

Tip: If, on a given day, you view the “Energy and power – battery” screen at the device level and then go through the monitoring menu (Figure 4) to switch to “Energy and power – battery” at the system level, the day that you had previously selected will be adopted.

Figure 4: Distinction between device and system level in Sunny Portal powered by ennexOS

Analyzing the details

Many customers will already know the Analysis Pro tool from the subscription-based Sunny Portal Professional Package. When purchasing an SMA Data Manager M (EDMM-10), the tool is currently available only as part of the “Monitoring and Control” bundle and includes a number of functions in the Data Manager software and in Sunny Portal. This means that the Analysis Pro tool is already included into Sunny Portal powered by ennexOS and now also includes a range of useful functions for analyzing battery systems. In addition to the familiar grid analysis features (active and reactive power, frequency and AC current and voltage), Analysis Pro now also offers various new analysis options for the battery itself. The following data can be displayed in five-minute intervals:

• State of charge (SOC) as %
• State of health (SOH) as %
• Battery charge and discharge power in W
• Battery temperature in °C
• Battery voltage and current in V/A
• Target charging voltage in V

This means that the SOC curve in the multicluster can be shown, for example (Figure 5), and that for the first time system errors can be detected at a glance in Sunny Portal. If a battery reaches a full state of charge very early or frequently becomes warmer than other batteries in the cluster, for example, this may indicate a battery defect, which means that the operator can take action to replace the battery before any unexpected system failure occurs. Measured values for all system devices can also of course be compared on a diagram (Figure 6), or the events that occurred during the period under analysis can be listed.

Tip: Operators can use the event monitor filter to gain a better overview of the events in a given period.

Figure 5: SOC of a multicluster visualized in Analysis Pro

Figure 6: Battery current and voltage compared on a diagram

Incidentally, in Sunny Portal powered by ennexOS, you can display deactivated or replaced devices via Analysis Pro with a single click. To do so, simply click the “Display shut-down devices” button and the entire system history will once again be shown.

The analysis tool helps you identify potential failures early on and saves both money and unnecessary work. Why not try it out for yourself?