1. Calculate the Ampere-Hours (Ah) requirement:
- Determine the total power consumption of the devices that will be connected to the UPS.
- Multiply the total power consumption in watts by the desired backup time in hours. This gives the total energy requirement in Watt-hours (Wh).
- Divide the total energy requirement (Wh) by the voltage of each battery (12V) to obtain the Ampere-hours (Ah) required from the batteries.
2. Determine the Battery Capacity:
- Choose 12V batteries with a suitable capacity to meet the calculated Ah requirement.
- Divide the total Ah requirement by the Ah capacity of each battery to determine the number of batteries needed.
For example, if the total power consumption is 400kW and you want a 30-minute backup time, the calculation would be as follows:
1. Total energy requirement (Wh) = 400,000W x 0.5h = 200,000Wh
2. Ah requirement = 200,000Wh / 12V = 16,667Ah
3. Assuming you use 12V batteries with 100Ah capacity, the number of batteries needed would be:
- Number of batteries = 16,667Ah / 100Ah ≈ 167 batteries
It's important to note that this calculation provides an approximate number of batteries required and does not account for inefficiencies and other factors that may affect the actual runtime. For a precise system design, it's best to consult with a qualified power systems engineer who can consider specific load requirements, UPS specifications, and environmental conditions.
