UPS Runtime Planning
A UPS battery runtime estimate helps you prepare for outages. It links the battery bank to the real equipment load. The result is not a fixed promise. It is a planning value based on entered conditions.
Battery capacity is usually printed in amp hours. Energy is found by multiplying voltage by amp hours. A UPS changes battery energy into AC output. That change loses some energy. The calculator therefore includes inverter efficiency.
Depth of discharge also matters. Many lead acid batteries last longer when they are not fully drained. Lithium packs may allow deeper discharge. Aging reduces available capacity each year. Heat, cold, and high current can reduce runtime further.
Advanced Inputs
This calculator supports series batteries and parallel strings. Series batteries raise voltage. Parallel strings raise amp hour capacity. The load can be entered in watts. Power factor converts watts into apparent load, which helps compare the result with UPS ratings.
The Peukert exponent adds a useful correction. Lead acid batteries deliver less capacity at high discharge current. A value near one gives a simple energy estimate. Higher values reduce runtime when the load is heavy.
Practical Use
Use this tool before buying batteries, adding servers, or testing emergency lighting. Enter the actual measured load when possible. Nameplate ratings can be higher than normal usage. Add a safety margin when the equipment is critical.
The output shows nominal energy, usable energy, DC current, AC load in VA, runtime hours, and runtime minutes. It also gives a backup time status. This makes it easy to compare several battery choices.
A runtime estimate should be checked with a real discharge test. Batteries can fail early. UPS alarms, charger faults, loose cables, and old cells can change results. Testing under safe supervision gives the best confidence.
Good planning keeps runtime realistic. It avoids guessing from battery size alone. It also shows when a larger UPS, extra battery string, or lower load is needed. For best results, review the calculation after each battery replacement or equipment change.
Keep a record of each estimate. Save CSV files for audits. Download PDF reports for job notes. Compare results over time, because capacity declines slowly before a failure becomes obvious during real outages.