EMERALD TECHNICAL PLANNING TOOL

UPS Backup Planning Tool

Estimate UPS capacity, battery quantity, runtime, current and preliminary equipment requirements for a backup power application.

Backup Power Planning

Preliminary UPS Backup Design Assistant

Battery Planning

Battery blocks per string: 40
Calculated DC bus voltage: 480V
Battery type: 12V 100Ah blocks
Parallel strings required: 2
Total batteries required: 80
Installed battery energy: 96,0kWh
Usable battery energy: 76,8kWh
Theoretical runtime before UPS battery correction: 72 minutes
Estimated UPS battery runtime achieved: 36 minutes

Technical Recommendations

60 kVA

Insufficient

80 kVA

Recommended

100 kVA

Consider where future load growth is expected

Battery Selection: The battery quantity is estimated from usable stored energy and required runtime. Final runtime must be confirmed against the UPS and battery manufacturer discharge data.

High-Rate Runtime Correction: UPS battery runtime is corrected for high-rate discharge. Actual runtime must be confirmed against the battery manufacturer discharge tables at the required end voltage and discharge current.

Runtime Scaling: Runtime is scaled by battery string count. This provides a planning estimate only. Final runtime must be confirmed against the UPS and battery manufacturer discharge tables.

Battery String Quantity: Battery block quantity depends on the UPS model and approved DC voltage range. Always confirm the allowable battery string quantity with the UPS manufacturer before final battery design.

Generator Support: Suggested generator starting point: 100 kVA. Generator support must consider UPS rectifier behaviour, battery recharge current, nonlinear loads, load step response, harmonics, altitude and ambient temperature.

Electrical Distribution: Indicative supply breaker: 125 A. Breaker and cable sizing must be coordinated with the final UPS model, cable installation method, voltage drop, fault level and discrimination requirements.

This planning tool provides a preliminary estimate only. UPS sizing, battery runtime and electrical distribution must be confirmed against manufacturer data sheets, battery discharge curves, SANS 10142 requirements and actual site conditions.

Battery runtime is affected by battery age, temperature, discharge rate, UPS efficiency and battery manufacturer performance data.

For VRLA UPS batteries, Ah capacity is normally rated over a long discharge period and cannot be used directly for short UPS runtimes without high-rate correction.

Where loads are mission-critical, consider redundancy, maintainability, bypass arrangements, generator compatibility and future expansion.

UPS Design Support

Need a detailed UPS design or quotation?

Send your UPS backup planning results to Emerald and our team can assist with UPS selection, battery sizing, generator compatibility, bypass arrangements and electrical distribution.

Request UPS Design Assessment