Four-channel electronic load/battery capacity tester

Introduction: Multi-channel electronic load/battery capacity tester based on STM32G0 low-cost solution

1. Product introduction

A multi-functional four-channel electronic load/battery capacity tester. Full touch screen operation, multi-parameter display, each channel can be set and operated independently.


2. Application scenario

power supply performance test, aging test, battery, power bank and other capacity tests, and use the battery according to its capacity.



3. Product Overview

The main control is a low-cost four-channel electronic load implemented based on STM32G070 MCU. Use internal built-in ADC sampling. PWM filtering serves as analog reference.

The load in constant voltage and constant current modes is adjusted by hardware, and modes such as constant resistance and constant power are adjusted by software.

The four channels can be set independently. There can be a maximum voltage difference of 1V between each channel.


4. Product parameters

The main parameters and performance are as follows:

1. Integrated four-channel electronic load/capacity tester

2. The maximum current of each channel is 3A and the voltage is 6V. Single channel full power 18W (maximum 25W). (The BOM and firmware can be modified to modify the range)

3. There can be a voltage difference of 1V between each channel to solve the problem of multi-channel output ground current direction.

4. Supports constant voltage load, constant current load, constant resistance load, and constant power load.

5. Support capacity AH, energy WH, running time, voltage, current, power and other parameter display.

6. Support temperature control intelligent fan control.

7. Support constant voltage or constant current mode indicator light display.

8. 4.3-inch serial screen display and setting parameters, touch screen control.

8. The graph curve shows the discharge trajectory.

9. 1% accuracy without calibration, 0.2%-0.5% accuracy after manual calibration.

10. The firmware is still being upgraded, and other functions will be expanded~~~


System parameters:

external 12V power supply, maximum current 0.5A.

The PCB adopts a double-layer board structure. Components

with dimensions of 18cm*14cm

adopt a single-sided layout.





5. Instructions for use/tutorial

Full touch screen parameter setting

homepage: four-channel electronic load, the current and voltage can be set as a whole,

waveform: displays the discharge voltage waveform,

parameter setting: the parameters of each channel can be set independently.

Capacity test: An interface for battery capacity testing.

System parameters:

Screen calibration is not supported for the time being: Screen calibration is not supported for the time being


6. Remarks:

This module requires downloading the code driver (software plus hardware). There are two modules in total that need to download the code.

They are MCU and serial port screen modules respectively.

The source code (MCU source file) is provided in the attachment, which can be opened and compiled through KEIL and downloaded for joint debugging through STLINK.

At the same time, the serial port screen module source code (serial port screen source file) is also provided in the attachment. The serial port screen uses Tao Jingchi's serial port screen, which can be opened through the built-in HMI software and downloaded through the serial port module.

The total production cost is about 350.

Accessories such as serial screens, power supplies, fans, etc. have purchase links in the attachments.

The "Four-channel electronic load source BOM+ purchase link" in the attachment contains purchase links for some unmounted devices.


7. Test video

The video shows the general operation process and basic functions.