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Warehouse Robot Battery Runtime Calculator

Estimate usable operating runtime for a warehouse robot robot from battery capacity and average electrical load. The calculator reduces nominal battery energy by a reserve threshold and discharge efficiency, then divides the usable energy by average power draw to estimate hours of operation before the reserve is reached.

This is helpful for shift planning, charging schedules, and early comparison of robot configurations. Average power should reflect the intended duty cycle rather than a single peak measurement because propulsion, compute, sensors, payload handling, and idle periods all affect consumption. Battery age, temperature, terrain, payload, acceleration, and charger strategy can change real-world runtime, so the estimate is best used as a planning baseline supported by field measurements.

Battery and load

kWh
kW
%
%
Result
—
Estimated operating runtime
Runtime—
Usable battery energy—
Energy used before reserve—
Equivalent full-battery fraction used—

1. Enter nominal battery capacity
Use the rated energy capacity of the installed battery in kilowatt-hours.

2. Enter average operating power
Use an average kW draw for the intended duty cycle, including motion, compute, and payload functions.

3. Set the reserve threshold
Enter the battery percentage you plan to leave unused before the robot stops or charges.

4. Apply discharge efficiency
Account for energy that is not converted into usable electrical work under operating conditions.

5. Use the runtime for scheduling
Compare the estimated hours with the shift length and charging opportunities.

Usable energy = Battery capacity × (1 − Reserve fraction) × Discharge efficiencyRuntime = Usable energy / Average power draw

Where:

  • Battery capacity = nominal stored energy in kWh
  • Reserve fraction = portion intentionally left unused at the end of operation
  • Average power draw = mean electrical demand in kW over the duty cycle
  • Runtime = estimated operating time in hours

Assumptions: Average power is constant over the modeled period and battery capacity is fully available apart from the entered reserve and efficiency adjustment. Degradation and temperature effects are not modeled separately.

What the result means

The runtime is the estimated time the robot can operate at the entered average power before reaching the chosen battery reserve.

Validate average power and usable capacity with telemetry from representative routes and payloads.

Given:

  • 12 kWh battery
  • 0.85 kW average power draw
  • 20% reserve
  • 91% discharge efficiency

Calculation:
Usable energy = 12 × (1 − 0.20) × 0.91 = 8.736 kWh. Runtime = 8.736 / 0.85 = 10.28 hours.

Result:
Estimated runtime ≈ 10.28 hours before the reserve threshold.

Interpretation:
The result provides a duty-cycle baseline; heavier payloads or more demanding routes can shorten actual runtime.

Why use average power instead of peak power?

Runtime depends on energy consumed over time. Peak draw matters for component sizing, but average draw across the duty cycle is more appropriate for an energy-runtime estimate.

Should I use the battery’s new or current capacity?

Use the best estimate of current usable nominal capacity. An aged battery may store less energy than its original rating.

What does the reserve percentage represent?

It is the state of charge you plan to leave when operation stops. A reserve can protect service continuity and avoid deep discharge.

How does payload affect this estimate?

Payload can raise propulsion or handling power. Reflect that effect in the average power input, ideally using measurements from comparable payloads and routes.

Does this calculate charging time too?

No. It estimates discharge runtime only. Charging time also depends on charger power, battery limits, tapering, and the target state of charge.