Difference Between 5kVA 48V and 24V Solar Inverters
The choice between a 5kVA 48V solar inverter and a 5kVA 24V solar inverter often hinges on the specific voltage requirements of your battery bank. Here's a detailed breakdown of the key differences:
Overview of the Differences
Both inverters share the same AC output power rating of 5kVA, but they require different input DC voltages from the battery bank. A 5kVA 24V inverter needs a 24V battery bank, while a 5kVA 48V inverter requires a 48V battery bank. Understanding these differences is crucial for selecting the right inverter for your solar power system.
Detailed Explanation of Both Setups
5kVA 24V Inverter
Battery Voltage: Assuming a lead-acid battery bank, the nominal voltage would be 24V, with a maximum recommended charging voltage of 28.8V and a low voltage cut-off of 22.8V.
Battery Construction: A 24V battery bank can be constructed by connecting two 12V lead-acid batteries in series, or by connecting 12 units of 2V lead-acid cells in series.
Voltage and Current: At a given power consumption, the current draw will be higher with a 24V inverter due to the lower voltage. For example, at 5kVA and a power factor of 0.8, the inverter can support loads up to 4000W. To meet this power requirement, the battery bank must supply 166.666A at 24V, necessitating thicker wires and busbars to handle the higher current.
Power Backup Duration: Due to the high current draw, lower capacity batteries, such as 150Ah, will discharge quickly. For instance, a 200Ah battery bank might last only 45 minutes under this load, requiring larger capacity batteries.
5kVA 48V Inverter
Battery Voltage: Again, assuming a lead-acid battery bank, the nominal voltage would be 48V, with a maximum recommended charging voltage of 57.6V and a low voltage cut-off of 45.6V.
Battery Construction: A 48V battery bank can be created by connecting four 12V lead-acid batteries in series, or by connecting 24 units of 2V lead-acid cells in series.
Voltage and Current: At 48V, the inverter requires half the current of a 24V inverter for the same power consumption, which is more efficient. For a 5kVA inverter at 0.8 power factor, the battery bank needs to supply 83.333A at 48V, leading to thinner but still robust wires and busbars.
Power Backup Duration: With a current draw of 83.333A, the battery bank will last longer. For example, a 150Ah battery bank can provide around 90 minutes of power, making it suitable for moderate to large battery banks.
Recommendations and Conclusion
Most manufacturers offer 5kVA inverters in 48V variants, although 72V, 96V, and 120V variants may be available. The 48V variant is the minimum voltage available and offers a balance between efficiency and cost. In contrast, the 24V variant is less efficient and more prone to maintenance issues due to higher current draws.
Based on these factors, it is highly recommended to use the 5kVA 48V inverter rather than the 24V inverter, as it provides a better balance of cost and performance.