150V 45A MPPT - roll your own


Author Message
nickskethisniks
Guru

Joined: 17/10/2017
Location: Belgium
Posts: 458
Posted: 10:51am 18 Nov 2023      

Depending on the amount or type of solar panels attached there runs a small reverse current during the night.
This could also contribute to the offset deviation.
I saw the LCD displays a current if you load the input (solar panels side) with a resistor.

An extra series diode or mosfet could fix that if you don't mind the extra loss.

I'm currently thinking about a new controller board, An extra opamp circuit with an adjustable offset (+-2.5V) could double the resolution and possible lower the offset fault.

Switching to an pin compatible lgt8f328 could also increase the 10 bit resolution to 12 bit. Without changing the code much. I have those running the lcd's with great result, I also have 1 for reading a pressure sensor in my rainwater buffer.

Another problem I have is when the controller is connected to a computer or something else the Vref is on a slightly different level. I had to add An external reference to the boards to do correct calibration.