Where the Power Goes
Measure current and find the big drains.
Where the Power Goes is a free Arduino & IoT Academy lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Arduino & IoT Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
The Battery Budget
A battery holds a fixed amount of energy. To run for months, you must understand exactly where every drop of power goes. 🔋
Measured in Milliamps
Power draw is measured as current in milliamps (mA). A board pulling 80mA from a 2000mAh battery drains it in just about a day.
Capacity vs Draw
Battery life is simply capacity divided by current. Cut the current ten times and your device runs ten times longer.
The Usual Power Hogs
The biggest drains are usually the WiFi radio, bright LEDs, and the regulator. Knowing the worst offenders tells you where to save.
WiFi Is Hungry
An active WiFi radio can spike to over 150mA. It is by far the heaviest cost in most battery IoT projects, so use it sparingly.
Measure, Do Not Guess
You cannot save power you cannot see. A multimeter in series with the supply shows the real current your device is pulling.
Reading Average Current
Current jumps around as the chip works. What matters for battery life is the average current over a full cycle, not the peak.
Onboard LEDs Add Up
That little power LED glowing on your board can sip several milliamps nonstop. On a tiny budget, even small constant draws matter.
The Regulator Tax
The voltage regulator wastes a steady current just being on. Cheap dev boards often leak more here than the chip itself uses.
Sleep Is the Big Win
An idle chip still burns real current. Putting it into sleep between tasks is the single most powerful way to extend battery life.
Estimate Before You Build
Add up each part's current, then divide your battery's capacity by that total. This quick estimate reveals if your goal is realistic.
long hours = 2000 / 80; // mAh / mA = approx runtimeQuick Check
Time to test what drives battery life.
Recap: Find the Drains
Battery life is capacity divided by current. Measure the real draw, hunt down WiFi, LEDs, and regulator waste, then lean on sleep. ⚡
Frequently asked questions
Is the “Where the Power Goes” lesson free?
Yes — the full text of “Where the Power Goes” is free to read here on the web, and the Arduino & IoT Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Arduino & IoT Academy course, upgrade to CoddyKit PRO.
What will I learn in “Where the Power Goes”?
Measure current and find the big drains. You practise Arduino & IoT Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Arduino & IoT Academy?
No prior experience is required. Arduino & IoT Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Where the Power Goes” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Arduino & IoT Academy lesson?
Yes. Every Arduino & IoT Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Where the Power Goes
- Enter ESP Deep Sleep
- Wake on Timer or Pin
- Design a Battery Sensor Node