5V Rechargeable Li-Po Battery Power Supply
Created by: Nicholas Gallagher
Date: 12/7/2024
Objective
Design a reliable 5V power Supply using two 3.7V 5000mAh LiPo batteries in parallel, an HW-373 v1.2.0 boost converter, and safety features such as a 5A fuse and a thermal switch.
Overview
- Batteries: 2 × 3.7V, 5000mAh (10,000mAh total)
- Boost Converter: HW-373 v1.2.0 (3.3–5V input, 5V output, ~90% efficiency)
- Fuse: 5A inline fuse to prevent overcurrent damage
- Thermal Switch: KSD9700 (Normally Closed), opens at 100°C
Battery Configuration: Series vs. Parallel
| Feature | Series | Parallel |
|---|---|---|
| Voltage | Adds up | Remains the same |
| Capacity | Same as one battery | Adds up |
| Current Output | Limited | Increases |
Runtime Calculation
Formula: Runtime = BatteryCapacity(mAh) × BatteryVoltage(V) / (DeviceCurrent(mA) × Efficiency)
| Device | Current (mA) | Runtime (hours) |
|---|---|---|
| Raspberry Pi 4B (Idle) | 600 | 13.7 |
| ESP32-EVB (Wi-Fi) | 500 | 16.4 |
| LED Strip (60 LEDs) | 1,200 | 6.8 |
Assembly Steps
- Wire batteries in parallel.
- Insert the 5A inline fuse.
- Install the KSD9700 thermal switch.
- Connect to the HW-373 boost converter.
- Test output voltage.
Bill of Materials (BoM)
| Component | Description | Quantity | Estimated Cost |
|---|---|---|---|
| LiPo Battery | 3.7V 5000mAh LiPo | 2 | $25.99 |
| Boost Converter | HW-373 | 1 | $9.99 |
| Thermal Switch | KSD9700 (100°C) | 1 | $8.99 |
| Fuse | 5A inline mini blade fuse | 1 | $4.99 |
pictures
