DIY 18650 Battery Capacity Tester PCB Build Battery Capacity Tester Project A DIY project to build a solid 18650 battery capacity tester with two discharge load settings. Introduction In this project, we will be building a battery capacity tester that can accurately measure the capacity of 18650 batteries. This type of tester is commonly used by hobbyists and professionals alike to determine the health and capacity of their batteries. The Problem with Cheap Battery Testers While cheap battery testers are readily available, they often come with limitations. They can be messy to work with and lack the precision needed for accurate measurements. The Solution: A Custom PCB Board To overcome these limitations, we will be designing a custom PCB board using EZEDA software. This board will feature two load resistance settings, each with a rating of 5W and 7.5 ohms. PCB Board Manufacture We used PCBGOGO service to manufacture our PCB board. Currently, they are offering a special promotion for 1-2 layer PCBs with dimensions of 100 x 100 mm for just $5. Components Used The following components were used in this project: Battery capacity tester board Two load resistance (5W and 7.5 ohms) 18650 battery holder Male header PCB standoffs Discharge Load Settings The tester features two discharge load settings. Without a jumper, the tester will discharge at 500 mAh. With a jumper, it will discharge at 1A. Conclusion This DIY project provides a cost-effective and accurate way to measure the capacity of 18650 batteries. By using a custom PCB board and carefully selecting components, we can create a reliable and efficient battery tester. Additional Resources A list of parts used in this project is available below. You can also find links to purchase these components online. Battery capacity tester board: [insert link] Load resistance (5W and 7.5 ohms): [insert link] 18650 battery holder: [insert link] Male header: [insert link] PCB standoffs: [insert link] Battery Tester Category: Electronics Testing Equipment Description: A battery tester is a device used to test the condition and performance of batteries, typically measuring voltage, current, and internal resistance. Background: Battery testers have been in use for decades, with early models using analog meters and later evolving to digital displays. The development of microprocessors enabled more sophisticated testing methods, including load testing and impedance measurement. Modern battery testers often feature advanced diagnostic capabilities, such as state-of-charge analysis and battery type identification. DIY 18650 Battery Capacity Tester PCB Build Introduction: If you're an enthusiast of DIY projects and want to test the capacity of your 18650 batteries, this article is for you. In this guide, we'll walk you through the process of building a PCB (Printed Circuit Board) based battery capacity tester using easily available components. Components Required: PCB board ATmega328P microcontroller LCD display (16x2 or 20x4) Battery holder for 18650 batteries Current sensing resistor (0.01 ohm) Voltage regulator (5V or 3.3V) Capacitors (10uF, 100nF, and 1uF) Resistors (1k, 4.7k, and 10k ohm) Circuit Diagram: The circuit diagram for the battery capacity tester is relatively simple. It consists of an ATmega328P microcontroller, which reads the voltage and current from the battery using a voltage divider network and a current sensing resistor respectively. The values are then displayed on the LCD display. PCB Layout: The PCB layout for this project is relatively simple and can be designed using any PCB design software such as Eagle, KiCad, or Fritzing. Make sure to follow the standard safety precautions while designing and etching the PCB. Assembly and Testing: Once the PCB is designed and fabricated, it's time to assemble the components. Start by soldering the microcontroller, voltage regulator, capacitors, and resistors to the board. Next, connect the LCD display, battery holder, and current sensing resistor. After assembling all the components, plug in a fully charged 18650 battery into the battery holder and turn on the device. The LCD display should show the initial battery voltage and capacity. Calibration: To ensure accurate readings, you'll need to calibrate the tester using a known fully charged battery. Connect the battery to the tester and note down the displayed voltage and capacity values. Next, discharge the battery completely (e.g., by connecting it to a load) and then recharge it again. Repeat this process several times until the displayed values stabilize. Usage: Using the battery capacity tester is straightforward: Insert a fully charged or partially discharged 18650 battery into the holder. The LCD display will show the current voltage and estimated remaining capacity of the battery. You can use this information to determine if the battery needs recharging or replacement. Conclusion: Building a DIY 18650 battery capacity tester using an ATmega328P microcontroller and a PCB is a fun and rewarding project that can help you monitor the health of your batteries. With this guide, you should be able to design and build your own battery tester and start monitoring your batteries in no time! Q1: What is a DIY 18650 Battery Capacity Tester PCB Build? A DIY 18650 Battery Capacity Tester PCB Build is a project that allows you to build your own Printed Circuit Board (PCB) to test the capacity of 18650 lithium-ion batteries. Q2: What components do I need for this project? You will need a PCB, an Arduino board, a LCD display, a battery holder, a current sensor, and some wires to connect everything together. Q3: What is the purpose of the current sensor in this project? The current sensor measures the discharge current of the battery, allowing you to calculate its capacity. Q4: How does the Arduino board fit into this project? The Arduino board acts as the brain of the project, reading data from the current sensor and LCD display, and calculating the battery's capacity. Q5: What kind of batteries can I test with this DIY tester? This DIY tester is specifically designed to test 18650 lithium-ion batteries, but you can modify it to test other types of batteries as well. Q6: How accurate is the capacity measurement with this DIY tester? The accuracy of the measurement depends on several factors, including the quality of the components and the calibration of the current sensor. However, with proper setup and calibration, you can achieve an accuracy of around 1-2%. Q7: Can I use this DIY tester to test battery health? No, this DIY tester is designed specifically for measuring battery capacity. If you want to test battery health, you will need a different setup and additional components. Q8: How long does it take to assemble the PCB? The assembly time depends on your level of experience with electronics and soldering. However, with proper preparation and attention to detail, you can assemble the PCB in about 1-2 hours. Q9: Do I need any special tools or skills for this project? You will need basic electronics knowledge, soldering skills, and some patience. Additionally, you may need a multimeter to measure the resistance of the current sensor. Q10: Can I modify or upgrade this DIY tester for other purposes? Yes, with the Arduino board as the core component, you can easily modify or upgrade the DIY tester to add new features or test different types of batteries. Rank Pioneers/Companies Description 1 Adafruit Industries A leading manufacturer of DIY electronics kits, including the popular "18650 Battery Shield" for Arduino. 2 SparkFun Electronics A well-known provider of DIY electronics components and kits, including a range of battery management solutions. 3 OSH Park A community-driven PCB manufacturing service that has enabled many DIY projects, including custom 18650 battery testers. 4 Instructables - LiPo Battery Tester A popular DIY tutorial platform that features a range of user-submitted projects, including custom 18650 battery testers. 5 EEVBlog - Dave Jones A renowned electronics enthusiast and blogger who has created several DIY projects, including a popular 18650 battery tester. 6 Tindie - Re-inventing the way we make things A community-driven marketplace for makers and DIY enthusiasts, featuring a range of custom PCBs and kits, including 18650 battery testers. 7 Seeed Studio A leading provider of DIY electronics components and kits, including a range of battery management solutions. 8 Open Energy Monitor An open-source project that provides a range of DIY energy monitoring solutions, including custom PCBs for battery management. 9 Gikfun (eBay seller) A popular eBay seller that specializes in DIY electronics components and kits, including custom PCBs for battery management. 10 BangGood A leading online retailer of DIY electronics components and kits, including a range of battery management solutions. Component Description Value/Part Number U1 Microcontroller ATmega328P-PU (or equivalent) R1-R4 Resistors for voltage divider 1kΩ (1% tolerance) R5, R6 Pull-up resistors for buttons 10kΩ (5% tolerance) C1-C3 Filter capacitors 100nF (ceramic, X7R or equivalent) C4, C5 Buffering capacitors for LCD display 10uF (electrolytic, low ESR) D1-D3 Schottky diodes for battery protection 1N5819 (or equivalent) J1, J2 Battery connectors 2-pin JST-XH (or equivalent) LCD1 LCD display module 16x2 characters, HD44780U-compatible SW1, SW2 Tactile buttons for user input 6mm x 6mm, normally open (NO) Schematic Diagram Notes: The circuit uses a simple voltage divider to measure the battery voltage. R1-R4 are used as a voltage divider to scale down the battery voltage to a level that can be measured by the microcontroller's ADC. C1-C3 filter out noise from the voltage measurements, while C4 and C5 provide buffering for the LCD display module. D1-D3 are Schottky diodes that protect the circuit from reverse polarity battery connections. Microcontroller Configuration: The ATmega328P microcontroller is configured to use an internal oscillator at 8 MHz. The FUSE bits are set to select the internal oscillator and enable the ADC. Software Requirements: The microcontroller runs a custom firmware written in C, using the AVR-GCC compiler. The code measures the battery voltage and calculates the capacity based on user input (e.g., battery type, discharge rate). PCB Layout Considerations: The PCB layout should ensure that the voltage measurement circuitry is isolated from other components to minimize noise and interference. Decoupling capacitors (C1-C3) are placed close to the microcontroller.