Before determining the storage battery capacity for a solar energy system, it is first necessary to understand the electricity demand of the customer. It is a decisive factor to choose the right inverter capacity and capacity of the battery/storage battery.
After calculating the daily energy usage, it is necessary to determine the energy demand for backup storage by performing the following calculations:
Table of contents
1. Inverter storage (offgrid or hybrid type)
Wattage inverter Okay decided by the maximum load of a household. We can calculated by adding all the power of different devices running at the same time. Need Make sure that the inverter power is greater than the total power of all devices.
For example: One household uses 1 air conditional running for 4 hours/day with a capacity of 1000W and 3 50W lights on for 5 hours, the total daily energy use will be 1,000 + 50 x 3 = 1,150W. So the inverter power needs at least 1,150W.
2. Daily electricity demand
Learn about customers' electricity needs to calculate inverter and battery capacity for solar energy storage systems.
To sum up the daily electricity demand, it is necessary to calculate how long each electrical appliance runs in a day and power multiples over time. Considering the performance loss, the real value would be result calculate multiply by 1.5.
Taking the same example above, the ideal daily energy usage is 1000 x 4 + 50 x 3 x 5 = 4,750WH and the actual daily energy usage is 4,750 x 1.5 = 7,125WH
3. Backup Energy Demand
Consider the capacity of the devices household appliances and backup energy needs to use for several hours or days. Let's say the goal is two days, and the devices are an air conditioner and three lights.
4. Backup battery/battery capacity for solar energy storage system
To calculate power the battery/storage battery energy (type lithium or GEL), need to calculate battery capacity suitable for inverter, especially when the voltage is determined by the output power of the solar panels in a household solar system.
Continuing the example above, with daily energy usage and a two-day power target, and determine how much to discharge 80% of the storage battery for the solar system, in order to maintain usage time of the battery for a longer usage cycle. The battery power should be 7,125kWh / 0.8 = 8,906.25 kWh, and further divided by the voltage of the solar system to convert to AH. If 48V is selected, the minimum AH capacity is 8,906.25/48 = 185Ah.
So we should choose 10kwh storage battery, and The inverter is recommended to use with a capacity of 5KW.
