IoT Power Consumption Calculator
Estimate average current, battery life, and the power cost of each IoT device phase.
IoT Power Consumption Calculator
Build a duty-cycle budget from sleep, sensing, compute, and radio phases. The animation shows where the device spends time, while the calculator shows which phase actually spends the battery.
Goal
Estimate battery life from current, phase duration, reporting interval, battery capacity, and efficiency.
Try First
Start with the LoRa soil node. Increase report interval, then reduce radio time. Watch average current fall.
Watch
The moving marker shows the active phase. Bars show energy share, not just time share.
Why It Matters
A device can sleep almost all day and still fail if radio bursts, sensors, or leakage are too expensive.
Timeline View
The timeline shows the duty cycle. Wide sections are time; tall bars are current.
Average Current Rule
Multiply each phase current by its duration, add the charges, then divide by cycle time.
Duty cycle turns burst current into average current.Battery Rule
Battery life is usable mAh divided by average mA.
Derating prevents unrealistic best-case promises.Optimization Rule
Fix the dominant charge contributor first.
Changing a small contributor has little effect.Beginner Ramp
- Current: flow of electrical charge, shown here in mA or uA.
- Capacity: a battery rating in mAh, meaning how long it can supply a current under test conditions.
- Duty cycle: the repeating pattern of sleeping, sensing, computing, and transmitting.
- Average current: the current that would spend the same charge as the whole cycle.
Quick Reference
- Phase charge in mA-s = current in mA x duration in seconds.
- Average current in mA = total phase charge / cycle seconds.
- Life in hours = usable battery mAh / average current mA.
- Life in days = hours / 24.
Decision Pattern
- Find the dominant energy share.
- Reduce its current, duration, or frequency.
- Check sleep current if active time is already tiny.
- Derate battery capacity before promising field life.
Model Notes
- This calculator assumes one repeated report cycle and approximate constant current within each phase.
- Usable capacity combines regulator efficiency, cutoff voltage, battery aging, temperature, and reserve margin into one beginner-friendly factor.
- Real radio events may include receive windows, association, retries, acknowledgements, and network join overhead.
Common Mistakes
- Using active current only and ignoring sleep current.
- Using sleep current only and ignoring radio bursts.
- Forgetting sensor warm-up time.
- Reporting battery life without derating capacity.
Technical Accuracy Notes
- mAh arithmetic is a first-order estimate when battery voltage and system voltage are similar or folded into the usable-capacity factor.
- For precise energy work, convert each phase to watt-seconds using voltage and regulator behavior.
- Battery capacity varies with load, temperature, chemistry, age, and cutoff voltage.
Practice 1
Select LoRa soil node. Increase the report interval until battery life passes one year. Notice which metric changes most.
Practice 2
Select GPS tracker. Reduce radio time and sleep current separately. Decide which change is worth more.
Practice 3
Select Wi-Fi sensor. Shorten transmit time, then compare the battery view with the breakdown view.