DIY Battery BMS
Reads a Victron Smart Shunt — over VE.Direct, Bluetooth or MQTT — and speaks Pylontech CAN to your inverter, so a DIY LiFePO4 pack can be charged, monitored and protected like a supported battery. No per-cell BMS wiring: just the shunt you already have.
Set it up from a browser, watch live charge state on its own dashboard, and hook it into Home Assistant over MQTT for automations like off-peak force charging.
Flash a board over USB
Plug an ESP32 in and this reads back what it is — chip, flash size, PSRAM, partition layout — then writes the build that matches it and sets it up on your WiFi. No drivers, no esptool, no zip to unpack.
Nothing is written until you have picked a build and confirmed the details. Your settings are kept where the build allows it — it says which before it starts — and can be saved to your PC first.
Anonymous, aggregate counts — no personal data collected.
Needs Chrome, Edge or Opera on a desktop, Firefox can work with a Firefox add-on to enable Web Serial.
Talking to the board…
Syncing with the bootloader and reading the flash layout.
What is on the other end of the cable
Chip
Flash layout
Read from the board.
How is CAN wired?
Do you have an MCP2515 on SPI or a built-in (ESP)CAN controller — this cannot be automatically detected. Please make a selection to continue, note if you are unsure, try ESPCAN if the CAN wiring is integrated, otherwise select MCP2515.
Before it writes anything
What gets written
Your settings
Writing to the board
DO NOT REMOVE the cable until this finishes.
Flashed, and the board has restarted
Network
This firmware is free and stays that way. If it saved you a weekend, buy me a coffee.
Put it on your network
The board is still on the cable, so it can take these now. Your passphrase goes down the USB lead to the board and nowhere else — this page has no server to send it to.
Or type it in
That did not work
A board already open in a serial monitor cannot be opened here as well — close it and try again. Some boards also need the boot button held while connecting.