Question 1

how to calculate battery bank size for 10kwh daily usage

Accepted Answer

To size a battery bank for 10kWh daily usage with 2 days of autonomy, multiply 10kWh by 2 to get 20kWh of usable capacity. If using Lithium Iron Phosphate (LiFePO4) batteries with a 90% Depth of Discharge (DoD), divide 20kWh by 0.90, resulting in a required total battery capacity of 22.2kWh. For lead-acid (50% DoD), you would need 40kWh.

Question 2

what size inverter do i need to run a 1500w air conditioner and fridge

Accepted Answer

To run a 1500W air conditioner and a 400W refrigerator simultaneously, your continuous running load is 1900W. However, the AC compressor requires a surge of 3x its running wattage (4500W) for 1-2 seconds. Therefore, you need a minimum 3000W continuous / 6000W surge pure sine wave inverter, preferably a 48V system to keep the current draw below 62.5 amps.

Question 3

how many 100ah 12v batteries do i need for 5kwh usable capacity

Accepted Answer

A 12V 100Ah battery holds 1200Wh (1.2kWh) of total energy. If using lithium batteries with an 80% Depth of Discharge (DoD), the usable capacity per battery is 960Wh (0.96kWh). To achieve 5kWh of usable capacity, divide 5000Wh by 960Wh, which equals 5.2. You will need a minimum of 6 batteries wired to reach a 48V 125Ah system (5.2kWh usable).

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