P150C Pro-D CNC Electronic Load Battery Capacity Tester

 
[This open source project specifically refers to the latest P150C Pro-D series DC constant current CNC electronic load]
The P100C/P150C/P150C Pro/P150C Pro-D series CNC electronic load is a DIY product, so its performance parameters cannot be compared with commercial products. However, due to its innovative and highly integrated circuit design, DIY production is very convenient, and the hardware data is open source, coupled with rich software functions, it has been highly praised by many players.
The following is the function interface:
 
 
 
Although this product is a constant current electronic load, a simple constant voltage mode is implemented through software, which is only used to measure power supplies with little voltage change, such as batteries.
 
In order to meet everyone's needs, various parameter adjustment settings are specially opened to make you more handy during DIY transformation.
The following is the setting interface:
 
 
 
 
 
 
 
 
The most important thing is to ensure the accuracy of each product, which is perfectly solved by the parameter calibration on the software.
The following is the parameter calibration interface:
 
The main features of the P150C Pro-D series CNC electronic load:
It uses the common DC5.5*2.1 port for power supply, and the original design inputs DC12V 1A. Using a 2.0-inch color LCD display, full Chinese prompts, and all parameters are displayed at a glance. It has overcurrent, overpower, overtemperature, overvoltage and other protections. It supports settings such as current, cut-off voltage, countdown, parameter calibration, etc. It supports normal constant current mode, automatic test, dynamic test and other functions. It supports one multi-function I/O, which can be set to multiple functions according to actual use. The cooling fan supports temperature control and speed regulation, and the mounting hole supports Intel 775 and 115x platform CPU coolers. Using a 24-bit high-precision energy metering chip, the theoretical measurement error is ≤±0.5% (0.5 level accuracy). Using a 4-wire differential input measurement, and using a 0.001Ω sampling resistor can minimize external losses.
 
From the P100C series at the beginning of the design to the latest P150C Pro-D series, it has gone through nearly 20 versions of design and took as long as 3 years. During this period, I received answers and guidance from many big guys such as Lao Feng, X II V, Lin ℃, Xiong Xian, etc., which allowed me to complete this product on the shoulders of giants. Although I dare not forget the advice from the big guys, I can only express my gratitude by thanking them at the end of the article. For me, every product I design must be mass-produced, otherwise it is meaningless. Therefore, the components selected are basically low-cost and easy to obtain. For players with higher requirements, they can go further on this basis by improving the stability of power supply, reference voltage, adjusting feedback loop, adjusting PCB wiring, etc., and enjoy the fun of tossing. We open a large number of parameters in the software for free adjustment, try not to limit your play, and we provide all the spare parts of the products that have been sold for a long time, which is convenient for maintenance and normal loss. You can contact me through platforms such as Xiaohuangyu and Xiaopenguin to buy.
 
In order to save editing time, most of the content is copied from the product user manual (yes, a very professional user manual is provided, and there are a few errors in the document that can be updated later). You can visit the website to get the user manual for detailed introduction: https://s.cnwans.com/P150CPro.
 
The schematic diagram, PCB source file and BOM table of the project can be downloaded in the attachment (the full set of materials is also packaged and published on the website for direct download), or edited online directly. After all, the schematic diagram is for your own use, so it doesn't matter if it's a little messy. At the same time, a simple operation demonstration video is provided in the attachment. The latest version of the firmware can be obtained in real time by visiting the website: https://s.cnwans.com/P150CProSoft. For some reasons, the program will not be open source, but the developer will update the firmware based on user feedback for a long time. The firmware needs to be registered before use in order to limit disorderly commercial use. The registration service is provided by the website (free registration, at least it can ensure that it is still valid when you see this project).
 
If you want to buy finished products or a full set of parts, you can search for P150C Pro electronic load on Xiaohuangyu (it is time-sensitive and will not be available for a long time). Special attention is: only the LCD screen is a rare item in this project. You can also contact me on Xiaohuangyu to buy the original one, or you can install the LCD screen of the same controller (ILI9225). There are a large number of various types on Taobao. When using it, you only need to modify the FPC pad. The information of the LCD screen: https://down.cnwans.com/archives/486. The rest of the components are from Taobao or LiChuang Mall. Why not use a common display screen? It can only be said that the developer developed the entire product to use this screen, rather than choosing this screen for the development of the product.
 
If you can't solve the problem of the LCD screen, there is a more compact and cute P100C series CNC electronic load for you to DIY. It uses the classic and easy-to-obtain 12864 black and white dot matrix screen (the screen contrast adjustment function provided in the firmware is compatible with all ST7567 controller LCD screens. You can choose to use Taobao's new, Lao Wang's inventory, POS machine disassembly, etc., as small as 1 inch and as large as 3 inches. Most of the components of the P100C series are consistent with the P150C Pro series, and its related information can also be obtained on the website.
 
Appreciate the original design of the P100C series CNC electronic load, which is only 5*10cm in size and can dissipate 100W of power:
 
The same integrated and perfect protection function:
 
 
The P100C series has been open sourced in 2020 (Digital Home Forum), so some players have improved the PCB. If you are interested, you can refer to some improved versions on the Internet.
By the way, the old P150C series was also open sourced in 2021 (Digital Home Forum). Both are powered by USB 5.0V. The disadvantage is that after the cooling fan is started, the insufficient USB current will cause certain interference to the system. Therefore, the P150C Pro series was changed to 12V input in the future design, and the latest P150C Pro-D series 9V~24V input.
 
Finally, you can play with this project freely, but you may not commercialize this project (small-scale production and sales are harmless). This project is reserved by cnwans.com.