DiY MPPT

This is an open source solar charge controller. Using Seeed Studio's PCB manufacture and PCB assembly this project was born!!

Seeed Studio XIAO ESP32C3: https://www.seeedstudio.com/Seeed-XIAO-ESP32C3-p-5431.html

Seeed Fusion PCB Assembly: https://www.seeedstudio.com/pcb-assembly.html

Seeed Studio Fusion : https://www.seeedstudio.com/fusion.html

The reason? to replace PWM charge controllers whilst it not being MPPT. MPPToneV14A40 uses 2 channels of synchronous buck converters, this allows for an efficiency of 96.2% @20V in 13.8V output and 45W (3.2amps) output !! By the way MPPT in MPPTone, is short for Maximum Power Point Topology. Not Maximum power point tracking. This simplifies the design many times, while keeping a high output power with little loss. On battery power this board uses less than 5Watts. (1.2w idle with wireless enabled)

A high solar panel voltage of 90V can be used. That is 3 average solar panels with a VOC of less than 30V each, which by design is also some of the cheaper products off the shelf. That makes it more budget friendly. ( Have only tested to 30v)

Here are two pictures representing some of my work on this project:

Want wireless?? No problem!!

This design uses a Seeed Xiao ESp32-C3 module for sampling, calculating, and displaying the measurements on a 128x64 Oled display. Optionally, you can add an expansion module to the board to manage and control other devices, such as lights, and DC to AC inverters. Sadly the code for the expansion module is not ready yet. But should be shortly.

As per test done in the past, I have been able to reach a maximum power output of 120W directly from the boards output. As it is not designed to be a Buck converter board but rather a charger, It cannot sustain high loads without having a battery connected...

I am not finished testing it yet. I have to test it thoroughly So that I can guarantee a reliable working project. But im working on a newer revision for those that are interested. Which will be smaller and lithium ion compatible..

My biggest issue right now is that I cannot get the current sensor to work properly, It is giving ghosted readings. I cannot seem to fix it..

Test Log:

1: sadly the current output is not even reaching 15A @ 13V

2: successfully got an input voltage of 68V and got 10.8A output.

3: Removed the current sensor and replaced it with an inductor. For an attempt in current filtering.

4: (2023/08/01) I got a 15A output @14.8V which is 230Watts!!

5:(2023/08/10) I successfully achieved MAX power with it 595Watts, which in fact can power the entire workspace i use. But im working on a Hardware revision 0.2 for even greater power and more efficiency.