
power-budget-calculator
Calculates total power consumption and battery life for Arduino/ESP32/RP2040 projects. Use when user asks about battery life, power requirements, current draw, or needs to estimate runtime. Includes sleep mode analysis, power optimization tips, and battery sizing recommendations. Run scripts/calculatepower.py for accurate calculations.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/wedsamuel1230/embedded-engineering-skills --skill power-budget-calculator- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads power-budget-calculator automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Power Budget Calculator
Estimates power consumption and battery life for embedded projects.
Resources
- scripts/calculate_power.py - Python calculator with component database, duty cycle support, battery life estimation
- references/component-database.md - Comprehensive current draw reference from datasheets
- assets/example-project.json - Sample project configuration
Quick Start
Run the calculator interactively:
uv run --no-project scripts/calculate_power.py --interactive
Or calculate for a single component:
uv run --no-project scripts/calculate_power.py --component ESP32 --mode deep_sleep --duty 95
Load a project configuration:
uv run --no-project scripts/calculate_power.py --json assets/example-project.json --output report.md
List all components in database:
uv run --no-project scripts/calculate_power.py --list
When to Use
- "How long will my battery last?"
- "What size battery do I need?"
- "How much current does my project draw?"
- Planning battery-powered projects
- Optimizing for low power
Workflow
Step 1: Gather Component List
Ask user for:
- Microcontroller (model and operating mode)
- All sensors and modules
- Displays
- Actuators (motors, LEDs, relays)
- Communication (WiFi, Bluetooth, LoRa)
- Operating profile (always on vs. duty cycle)
Step 2: Calculate Power Budget
Run scripts/calculate_power.py --interactive for guided calculation, or use this template:
# Power Budget: [Project Name]
## Operating Conditions
- Supply Voltage: [V]
- Operating Modes: [Active/Sleep cycles]
- Duty Cycle: [X% active, Y% sleep]
## Component Current Draw
### Always-On Components
| Component | Voltage | Current | Power | Notes |
|-----------|---------|---------|-------|-------|
| [name] | [V] | [mA] | [mW] | [conditions] |
| ... | ... | ... | ... | ... |
| **Subtotal** | - | **[mA]** | **[mW]** | - |
### Active Mode Only
| Component | Voltage | Current | Power | Duty % |
|-----------|---------|---------|-------|--------|
| [name] | [V] | [mA] | [mW] | [%] |
| ... | ... | ... | ... | ... |
| **Subtotal** | - | **[mA]** | **[mW]** | - |
### Peak Current Events
| Event | Current | Duration | Frequency |
|-------|---------|----------|-----------|
| [WiFi TX] | [mA] | [ms] | [per hour] |
| ... | ... | ... | ... |
## Power Calculations
### Average Current
I_avg = (I_active × t_active + I_sleep × t_sleep) / t_total I_avg = ([X]mA × [Y]s + [Z]mA × [W]s) / [T]s I_avg = [result] mA
### Battery Life Estimate
Capacity: [X] mAh Efficiency factor: 0.8 (80% usable) Effective capacity: [X × 0.8] mAh
Runtime = Effective capacity / I_avg Runtime = [X] mAh / [Y] mA Runtime = [Z] hours ([days] days)
## Recommendations
- [Power optimization suggestions]
- [Battery type recommendation]
- [Sleep mode configuration]
Current Draw Database
Microcontrollers
Arduino (ATmega328P @ 5V)
| Mode | Current | Notes |
|---|---|---|
| Active (16MHz) | 15-20mA | No peripherals |
| Idle | 6mA | CPU stopped, peripherals on |
| Power-down | 0.1µA | Only WDT/external interrupt |
| With USB-Serial | +50mA | CH340/FTDI chip always on |
ESP32 (WROOM-32)
| Mode | Current | Notes |
|---|---|---|
| Active (WiFi TX) | 160-260mA | Peak during transmission |
| Active (WiFi RX) | 95-100mA | Listening |
| Active (no WiFi) | 20-68mA | CPU only |
| Modem-sleep | 20mA | WiFi off, CPU on |
| Light-sleep | 0.8mA | CPU paused |
| Deep-sleep | 10µA | RTC only |
| Hibernation | 5µA | RTC off |
ESP32-C3
| Mode | Current | Notes |
|---|---|---|
| Active (WiFi TX) | 320mA peak | Brief spikes |
| Active (BLE) | 50-100mA | During advertising |
| Active (no radio) | 25-35mA | CPU at 160MHz |
| Light-sleep | 130µA | Auto wake |
| Deep-sleep | 5µA | RTC on |
RP2040 (Pico)
| Mode | Current | Notes |
|---|---|---|
| Active (both cores) | 25-50mA | Depends on clock |
| Single core | 15-25mA | One core dormant |
| Dormant | 0.18mA | Wake on GPIO/RTC |
| Sleep | 1.3mA |
RP2040 (Pico W)
| Mode | Current | Notes |
|---|---|---|
| WiFi active | 50-150mA | During TX |
| WiFi idle | 30-40mA | Connected, listening |
| WiFi off | 25-50mA | Radio disabled |
Sensors
| Sensor | Active | Sleep | Notes |
|---|---|---|---|
| DHT22 | 1.5mA | 50µA | During read |
| BME280 | 0.35mA | 0.1µA | Forced mode |
| BMP280 | 0.27mA | 0.1µA | |
| MPU6050 | 3.8mA | 5µA | All axes |
| DS18B20 | 1.5mA | 1µA | During conversion |
| HC-SR04 | 15mA | 2mA | No true sleep |
| VL53L0X | 19mA | 5µA | During ranging |
| MAX30102 | 600µA | 0.7µA | Low power mode |
| BH1750 | 120µA | 1µA | Power down mode |
| GPS (NEO-6M) | 45mA | 11mA | Backup mode |
Displays
| Display | Active | Off/Sleep | Notes |
|---|---|---|---|
| 16x2 LCD (backlight) | 80-120mA | 1mA | Backlight dominates |
| 16x2 LCD (no backlight) | 1-2mA | 1mA | |
| SSD1306 OLED 128x64 | 8-20mA | 10µA | Depends on content |
| SSD1306 OLED 128x32 | 5-15mA | 10µA | |
| ST7735 TFT | 20-40mA | 20mA | Backlight always on |
| ILI9341 TFT | 50-80mA | 50mA | |
| E-Paper 2.9" | 8mA | 0µA | Only during refresh |
Communication Modules
| Module | TX Peak | RX/Idle | Sleep | Notes |
|---|---|---|---|---|
| ESP8266 (module) | 170mA | 70mA | 20µA | Deep sleep |
| NRF24L01 | 11.3mA | 13.5mA | 0.9µA | |
| HC-05 Bluetooth | 40mA | 8mA | 2mA | |
| RFM95 LoRa | 120mA | 10mA | 0.2µA | |
| SIM800L GSM | 2A peak | 15mA | 1mA | Needs big cap! |
Actuators
| Component | Current | Notes |
|---|---|---|
| LED (typical) | 10-20mA | Through resistor |
| RGB LED (each color) | 20mA | Per channel |
| WS2812B NeoPixel | 60mA max | Full white |
| SG90 Servo (idle) | 10mA | No load |
| SG90 Servo (moving) | 200-500mA | Under load |
| MG996R Servo | 500-900mA | Under load |
| Small DC motor | 100-500mA | Varies with load |
| 5V Relay module | 70-100mA | Coil energized |
| Buzzer (passive) | 30mA |
Sleep Mode Configurations
ESP32 Deep Sleep Template
#include <esp_sleep.h>
#define uS_TO_S_FACTOR 1000000ULL
#define TIME_TO_SLEEP 60 // seconds
void setup() {
// Do measurements here
// Configure wake-up source
esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);
// Enter deep sleep
esp_deep_sleep_start();
}
void loop() {
// Never reached
}
Arduino Power-Down Template
#include <avr/sleep.h>
#include <avr/wdt.h>
void enterSleep() {
set_sleep_mode(SLEEP_MODE_PWR_DOWN);
sleep_enable();
sleep_mode(); // Sleep here
sleep_disable();
}
// Wake on watchdog or external interrupt
ISR(WDT_vect) {
// Wake up
}
Power Optimization Checklist
Hardware
- Remove power LED (saves 5-10mA)
- Remove USB-Serial chip for battery operation
- Use LDO with low quiescent current (<10µA)
- Add MOSFET to power-gate high-current peripherals
- Use pull-downs on unused pins
- Disable ADC when not reading
Software
- Use sleep modes between readings
- Reduce clock speed if possible
- Batch data and transmit less frequently
- Turn off WiFi/BLE when not needed
- Disable brown-out detector in deep sleep
- Use interrupts instead of polling
Design Patterns
Power Gating:
VCC
│
[P-MOSFET] ← GPIO (LOW = ON)
│
[Sensor/Module]
│
GND
Duty Cycling Formula:
I_average = (I_active × T_active + I_sleep × T_sleep) / T_total
Example: Sensor reads every 5 minutes
- Active: 50mA for 2 seconds
- Sleep: 10µA for 298 seconds
I_avg = (50mA × 2s + 0.01mA × 298s) / 300s
I_avg = (100 + 2.98) / 300
I_avg = 0.34mA
With 2000mAh battery:
Runtime = 2000mAh × 0.8 / 0.34mA = 4706 hours = 196 days
Battery Reference
Common Battery Types
| Type | Voltage | Typical Capacity | Notes |
|---|---|---|---|
| CR2032 | 3V | 220mAh | Very low current only |
| 2x AA Alkaline | 3V | 2500mAh | Good for low power |
| 3x AA Alkaline | 4.5V | 2500mAh | Direct to 5V systems |
| 4x AA Alkaline | 6V | 2500mAh | With LDO to 5V |
| 18650 Li-ion | 3.7V | 2000-3500mAh | Rechargeable, popular |
| LiPo 1S | 3.7V | Various | Flat, light |
| 9V Alkaline | 9V | 500mAh | Poor energy density |
Voltage Over Discharge
18650/LiPo Discharge Curve:
Capacity% Voltage
─────────────────────
100% 4.2V
80% 3.9V
50% 3.7V
20% 3.5V
0% 3.0V (cut-off!)
Never discharge below 3.0V - damages cell!
Alkaline AA Discharge:
Capacity% Voltage (per cell)
─────────────────────────────
100% 1.5V
50% 1.2V
0% 0.9V
Many devices stop working below 1.1V/cell
Quick Calculator
Enter your values:
Always-on current: ______ mA
Active current: ______ mA
Active time: ______ seconds
Sleep current: ______ mA
Sleep time: ______ seconds
Battery capacity: ______ mAh
Average current = (Active_mA × Active_s + Sleep_mA × Sleep_s) / Total_s
= (_____ × _____ + _____ × _____) / _____
= _____ mA
Runtime = Capacity × 0.8 / Average_current
= _____ × 0.8 / _____
= _____ hours
= _____ days
Shared Output Contract
Use the shared Arduino skill contract: state assumptions, required tools and versions, implementation steps, tests/evidence by proof stage, known limitations, and recovery/security notes.
FAQ
What does the power-budget-calculator skill do?
Calculates total power consumption and battery life for Arduino/ESP32/RP2040 projects. Use when user asks about battery life, power requirements, current draw, or needs to estimate runtime. Includes sleep mode analysis, power optimization tips, and battery sizing recommendations. Run scripts/calculatepower.py for accurate calculations.
How do I install power-budget-calculator?
Run npx skills add https://github.com/wedsamuel1230/embedded-engineering-skills --skill power-budget-calculator in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/power-budget-calculator/ (personal) or .claude/skills/power-budget-calculator/ (project).
Which AI agents can use power-budget-calculator?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is power-budget-calculator safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains power-budget-calculator?
It is published by wedsamuel1230 in wedsamuel1230/embedded-engineering-skills. It has 161 recorded installs.
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