How to calculate battery capacity for **off-grid solar systems**

- Determine the total power of the load. Note that it is the load power, not the rated power of the power supply.
- Determine the emergency time.
- 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 )*time*battery 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)*2*1=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;

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