Energy Harvesting Calculator Tool
Configure an IoT node, choose an energy source, size reserve storage, and decide whether the design can run without regular battery replacement.
Energy Harvesting Calculator Tool
Build a first-pass energy budget for a self-powered IoT node. The model compares harvested energy, load energy, and reserve storage so the learner can see why average power and outage reserve must both work.
Goal
Find whether a harvesting source and reserve store can support the selected IoT workload.
Try First
Compare the room sensor preset with RF harvesting, then watch daily balance and reserve change.
Watch
The energy trace, storage tank, sizing equations, and design flags update together.
Why It Matters
A design can have enough average energy but still fail when the source is unavailable.
Day View
The 24-hour trace shows when harvested energy enters storage and when the load consumes energy.
Harvest Equation
Ppeak = source x size x efficiency.
Pavg = 7.68 mW x 10/24 = 3.20 mWLoad Equation
Average current combines active and sleep current.
Iavg = 260 uA, Pload = 0.86 mWStorage Sizing
Supercapacitor reserve uses the usable voltage window.
Cmin = 24.5 F for 24 h reserveBeginner Ramp
Energy harvesting has two separate questions:
- Daily balance: harvested energy over a day should exceed load energy.
- Reserve: stored energy should run the node when the source is absent.
- Duty cycle: short active bursts can still dominate average load.
Core Formulas
Average harvest: Pavg = Ppeak x useful hours / 24.
Average load: Iavg = Iactive x duty + Isleep x (1 - duty).
Supercap: E = 0.5 C (Vhigh^2 - Vlow^2).
Battery: Eusable = mAh x V x usable fraction.
Quick Reference
- Use margin because source power varies with weather, placement, vibration, or RF exposure.
- Reserve storage covers night, shutdowns, or quiet periods.
- RF harvesting is usually only for very low-duty tags or sensors.
Source Notes
Solar depends on area and light. Vibration depends on coupling to the moving structure. Thermal depends strongly on sustained delta-T. RF depends on available field strength and rectifier losses.
Storage Notes
A supercapacitor can deliver many cycles but has limited energy. A rechargeable cell stores more energy but adds charge-management, cycle-life, and safety constraints.
Accuracy Notes
This is a teaching calculator, not a final hardware design. Real systems require measured source profiles, converter startup checks, leakage current, temperature derating, and worst-case load testing.
Practice 1
Select RF for the asset tag. Reduce active time until daily balance becomes positive.
Practice 2
Select bridge monitor and lower useful hours. Decide whether storage or source power fails first.
Practice 3
Switch to recharge cell storage and compare reserve hours with the supercapacitor result.