Victron Display

Introduction

This is an experimental repo. My goal is to parse the VE.Direct protocol from Victron with TinyGo on a Raspberry Pico.

See specifications of the protocol here

I want to have a display in my van to see :

• Battery voltage and current
• Solar panel Voltage and Current
• Current State of the MPTT Controller
• Maximum power
• Minimum and maximum voltage

Roadmap:

• Parsing VE.Direct protocol
• Connect to the MPTT
• Flashing the pico nano with firmware
• Refactoring to avoid heap allocations
• Add a display
• Add a button
• Testing
• Optimizing and reliability

Basic concepts

Hardware

flowchart LR
    MPTT(Victron MPTT) --> R[Rasp Pico];
    R --> LCD;

Loading

Software

flowchart LR
    R["serial data"] --> P[Parsing];
    P -- "map[string]string{}" --> Frame;
    Frame -- "struct{}" --> State;

Loading

Hardware

Socket

You will need a JST PH 4 female socket to connect your Victron device to the Raspberry

Microcontroller

In this POC I used a Rasbberry Pico, cheap and well supported by TinyGO: https://tinygo.org/docs/reference/microcontrollers/pico/

Flash the pico

tinygo flash -target=pico main.go

Testing the VE.Direct parsing lib

go test -v ./vedirect

It relies on a dump of my SmartSolar 100/20

Build and track heap allocation

More info available here.

As you may see, I had to modify a bit my usual gopher habits to reduce the number of heap allocations, in order to optimize the memory management of the microcontroller.

Here some adjumemts

• no pointer in "constructor like" method (aka New() (*myStruct, err))
• passing by value instead of reference in method :
  • ex func (m *myStruct) myMethod error --> func (m myStruct) myMethod (m myStruct, err error)

tinygo build -o firmware.uf2 -target=pico -print-allocs=. 2> >(grep victron)

Pico Pinout