The ESP32-CAM is a powerful microcontroller with built-in Wi-Fi, Bluetooth, and a camera interface, but it can be power-hungry—especially when using Wi-Fi and the onboard camera. If you're looking to make your ESP32-CAM project portable, one of the best power solutions is to use a pair of 18650 Li-ion batteries, along with a USB charging circuit and a boost converter to provide a regulated 5V.
This guide will show you how to do that safely and efficiently.
⚙️ Why 18650 Batteries?
18650 lithium-ion cells are widely available, rechargeable, and offer a high energy density—making them perfect for mobile IoT and embedded systems. Each cell provides a nominal 3.7V, but the ESP32-CAM requires 5V at its input pin. To meet this requirement, we’ll boost the battery voltage to 5V using a step-up (boost) converter.
🧰 Components You’ll Need
| Component | Description |
|---|---|
| 2× 18650 Li-ion Batteries | Preferably with the same brand and capacity |
| 1× TP4056 Charging Module | With battery protection (important for safety) |
| 1× MT3608 Boost Converter | Adjustable output voltage, input 2–24V |
| Wires, Soldering Tools, Capacitor (optional) | For assembly and stability |
🔋 Why Use Batteries in Parallel?
There are two ways to use two 18650 cells:
- Series (7.4V): You’ll get double the voltage, but charging requires a special balanced charger, and it’s risky if not done properly.
- Parallel (3.7V): You get double the capacity at the same voltage and can safely use a simple TP4056 charger.
✅ For safety, simplicity, and USB charging support, we’ll connect the batteries in parallel.
🔌 Circuit Connection Overview
Here’s how to connect everything:
-
Connect the batteries in parallel:
- Positive terminals of both batteries → B+ of TP4056
- Negative terminals of both batteries → B- of TP4056
-
Connect the TP4056 output to the boost converter:
- OUT+ of TP4056 → IN+ of MT3608
- OUT- of TP4056 → IN- of MT3608
-
Set the boost converter to 5V:
- Use a multimeter to adjust the potentiometer on the MT3608
- Once you get exactly 5.0V, connect it to ESP32-CAM:
- OUT+ of MT3608 → ESP32-CAM 5V pin
- OUT- of MT3608 → ESP32-CAM GND pin
-
(Optional) Add a 470µF or 1000µF capacitor between 5V and GND near the ESP32-CAM to handle current spikes during Wi-Fi transmission.
📝 Circuit Diagram (Text Format)
⚡ Performance Benefits
| Feature | Description |
|---|---|
| Rechargeable | Charged via USB Micro on TP4056 |
| Portable | Battery-powered operation |
| Reliable Power | Boosted 5V for ESP32-CAM operation |
| Safe Charging | TP4056 includes overcharge/discharge protection |
| Extended Runtime | 2× battery capacity in parallel configuration |
⚠️ Important Safety Notes
- Use protected 18650 cells or ensure the TP4056 module includes battery protection circuitry.
- Never mix batteries with different capacities or brands.
- Always check the output voltage from the boost converter before connecting to the ESP32-CAM.
- If the MT3608 gets hot, consider adding a small heatsink.
- Avoid powering the ESP32-CAM from the 3.3V pin unless you use a clean and stable external 3.3V regulator.
✅ Conclusion
Using a pair of 18650 Li-ion batteries with a TP4056 USB charging module and an MT3608 boost converter is a powerful and safe way to run the ESP32-CAM off-grid. It’s an excellent solution for portable camera projects, surveillance systems, or mobile IoT setups.
Would you like a visual schematic or printable wiring diagram to add to your blog post? Let me know and I can generate one for you.
