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Solar Battery Capacity Formula:
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The solar battery capacity calculation determines the required battery size (in amp-hours) for a solar power system based on inverter size, desired backup hours, and battery voltage. Proper sizing ensures sufficient energy storage for your needs.
The calculator uses the formula:
Where:
Explanation: The formula converts inverter kVA to watts (×1000), multiplies by hours to get watt-hours, then divides by voltage to get amp-hours.
Details: Correctly sizing your solar battery bank ensures you have enough stored energy for your needs without overspending on unnecessary capacity. Undersized batteries may not provide enough backup, while oversized systems are unnecessarily expensive.
Tips: Enter solar inverter size in kVA, desired backup hours, and battery bank voltage (typically 12V, 24V, or 48V for solar systems). All values must be positive numbers.
Q1: What's the difference between kVA and kW?
A: kVA is apparent power (including reactive power), while kW is real power. For solar systems with power factor correction, they're often similar (kVA ≈ kW).
Q2: How many batteries do I need?
A: Divide the calculated Ah by your individual battery's Ah rating. For example, if you need 200Ah and use 100Ah batteries, you'll need 2 in parallel.
Q3: What's a typical backup time for solar systems?
A: Most residential systems aim for 5-10 hours of backup, while critical systems may need 24+ hours.
Q4: Should I add a safety margin?
A: Yes, it's recommended to add 20-30% to the calculated capacity to account for inefficiencies and battery aging.
Q5: What battery voltage should I choose?
A: 12V is common for small systems, 24V for medium, and 48V for larger installations as higher voltages reduce current and wire sizes.