Inverter Battery Capacity Calculator

Inverter Battery Capacity Formula:

\[ Capacity (Ah) = \frac{Inverter Power (W) \times Backup Hours (h)}{Voltage (V) \times Depth of Discharge (DoD)} \]

Inverter Power:

Backup Hours Needed:

Battery Voltage:

Depth of Discharge (DoD):

decimal (0-1)

Required Battery Capacity:

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1. What is Inverter Battery Capacity?

The inverter battery capacity calculation determines the required battery size (in Amp-hours) to power your devices for a specific duration, considering the inverter's power output, battery voltage, and depth of discharge.

2. How Does the Calculator Work?

The calculator uses the following equation:

\[ Capacity (Ah) = \frac{Inverter Power (W) \times Backup Hours (h)}{Voltage (V) \times Depth of Discharge (DoD)} \]

Where:

\( Inverter Power \) — The continuous power output of your inverter in Watts
\( Backup Hours \) — Desired runtime in hours
\( Voltage \) — Battery bank voltage (typically 12V, 24V, or 48V)
\( Depth of Discharge \) — Fraction of battery capacity that can be used (typically 0.5 for lead-acid)

Explanation: The equation calculates the total energy needed (Watt-hours) and converts it to battery capacity (Amp-hours) considering the battery voltage and how much of the battery's capacity can actually be used.

3. Importance of Proper Battery Sizing

Details: Correct battery sizing ensures your inverter system can power your loads for the required duration without damaging the batteries or experiencing unexpected shutdowns.

4. Using the Calculator

Tips: Enter inverter power in Watts, desired backup time in hours, battery bank voltage, and depth of discharge (typically 0.5 for lead-acid batteries, 0.8-0.9 for lithium). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is Depth of Discharge (DoD)?
A: DoD indicates how much of the battery's capacity can be used. For example, 0.5 means only 50% of the battery's capacity should be used to prolong its life.

Q2: What's the typical DoD for different battery types?
A: Lead-acid: 50%, AGM: 70-80%, Lithium-ion: 80-90%.

Q3: Should I add a safety margin?
A: Yes, it's recommended to add 10-20% to the calculated capacity to account for inefficiencies and battery aging.

Q4: How does battery voltage affect capacity?
A: Higher voltage systems require lower Ah capacity for the same power output. For example, a 24V system needs half the Ah of a 12V system for the same Watt-hours.

Q5: Can I connect multiple batteries?
A: Yes, batteries can be connected in series to increase voltage or in parallel to increase capacity, following proper wiring guidelines.