How to Calculate Battery Capacity in Off-Grid Solar Systems

How to calculate battery capacity for off-grid solar systems

1. Determine the total power of the load. Note that it is the load power, not the rated power of the power supply.
2. Determine the emergency time.
3. Determine the DC voltage level of the power supply.

10kw photovoltaic system
Solar photovoltaic system battery capacity method: 1: Determine the total power of the load, pay attention to the load power, not the rated power of the power supply; 2: Determine the emergency time; 3: Determine the DC voltage level of the power supply; The formula is: (Load power/DC voltage )timebattery coefficient=single-cell battery voltage number of cells=DC voltage/single-cell battery voltage battery coefficient: 1.6 within half an hour; 1.4 from half an hour to 1 hour; 1 for more than 1 hour;.

For example: The customer wants a 5KVA UPS, the load is a 3KW light bulb, and it needs a 2-hour emergency, you need to provide a battery; the load power is 3000W; the emergency time is 2 hours; the DC voltage level of the UPS is 192V; (3000 /192)21=31.5, find the surrounding capacity battery, you can use 30AH/12V battery or 33AH/12V battery; the number of battery cells = 192/12V = 16 cells; so this solution can use 30AH/12V battery 16 cells or 16 cells of 33AH/12V batteries; For DC screens and communication power supplies, customers will generally directly tell how many A the system is, or how many AH the system is; 100AH means that 100A can be discharged in 1 hour, but the battery discharge coefficient must be considered ; The time is too short to actually discharge 100A; but the battery with a 10-hour discharge rate discharges 10A per hour and can be discharged for 10 hours;