How Many KVA of Inverter Can Be Connected to 20 Batteries?

When considering the connection of an inverter to a battery bank, it's essential to understand that the capacity is not only about the number of batteries but also their voltage and ampere-hour (Ah) capacity. In this article, we explore how to determine the appropriate KVA of inverter that can be connected to a set of 20 batteries, along with key considerations and practical examples.

Understanding Battery Specifications

In this scenario, we assume 20 batteries, each with a 12-volt rating, which is a common setup for inverters in the region of Asia and Africa. To determine how much KVA of inverter can be connected, we need to understand important battery specifications such as voltage and ampere-hour capacity.

Calculating KVA Capacity from Battery Voltage and Ah

First, let's break down the process of calculating the KVA capacity from the battery specifications. The formula for this calculation is as follows:

Input Voltage (DC) x Ah Capacity Capacity in Watts

For instance, if you have 12-volt batteries and a total ampere-hour capacity of 65 Ah, the calculation would be:

12 volts DC x 65 ampere-hours 780 watts

However, it's important to note that this capacity is generally stated at a specific rate of discharge. A typical battery capacity is rated at a 20-hour rate, meaning the battery can supply a certain amount of current over a 20-hour period.

Example Calculation

Consider the following example:

Voltage of the batteries: 12 volts DC Ampere-hour capacity: 500 Ah

The resulting capacity would be:

12 volts DC x 500 Ah 6,000 watts 6 KVA

Thus, a system with a total of 20 12-volt batteries can potentially support a 6 KVA inverter when properly configured.

Practical Considerations for Inverter Selection

There are several factors to consider when selecting an inverter for a battery bank:

Input Voltage and Phase

Modern inverters typically use a 240-volt DC input to ensure a sufficient backup for the load. This is especially important when the inverter is rated for a maximum load of 16 kW with a power factor of 0.8. Smaller inverters, such as those rated 10 KVA or 15 KVA, might also use this 20-battery setup if the required input voltage is 240 volts DC.

Battery Configuration

The configuration of the batteries (series, parallel, or a combination) also affects the total voltage and capacity. For a 20-battery setup, the total nominal voltage would be:

Total Voltage 12 volts DC x 20 units 240 volts DC

The capacity would be:

Total Capacity 65 Ah x 20 units 1,300 Ah (or 1.3 kAh)

This configuration can store a total energy of:

Energy 240 volts DC x 1,300 Ah 312,000 watt-hours 312 kWh

Sizing the Inverter

Given the total energy storage (312 kWh), if the inverter is required to supply 16 kW at 80% efficiency, the KVA rating would need to be calculated based on the inverter's specific efficiency and load requirements.

Conclusion

The capacity of an inverter that can be connected to 20 batteries is determined by the voltage and ampere-hour capacity of the batteries. By understanding and calculating these parameters, you can choose the appropriate inverter for your system. Remember that the configuration of the batteries, their voltage, and Ah capacity all play crucial roles in the selection process.

For more detailed information on inverter sizing and battery configuration, please refer to our other articles on similar topics.

Keywords: KVA, Inverter, Battery Power