This is a hobby project and I add features as and when I have time, it means sometimes it's not updated for a while and then sometimes I add a number of features!
You can now sponsor and donate to me, the link is on here to buy me a coffee ;)
The new UI means no coding knowledge is required, just flash and set up.
DiyBatteryBMS takes data from a Victron Smart Shunt and sends it to a inverter over CAN using Pylontech protocol allowing for "DIY LifePO4" Batteries to be integrated.
The Victron Smart Shunt provides the actual monitoring data, this software translates it to Pylontech protocol that most Inverters understand, the part that you need to configure is the charging voltage, current that is also sent to the Inverter.
As long as the Inverter accepts Pylontech protocol over CAN Bus this software should work with it, it's tested with Solis Inverters but forum users have reported it working with others.
The data is also sent over MQTT and allows commands to be sent back to control Charge/Discharge/Force Charge.
This software supports:
- ESP32 developer boards with MCP2515 CAN Bus adapter
- ESP32 with built-in CAN controller
- NEW: ESP32-S3 with built-in CAN controller (using TWAI driver)
If you don't use the Lilygo CAN485 board, you will need to add a CAN transceiver to your ESP32 or ESP32-S3 board.
See the WIKI for more detailed documentation.
With the help of the MQTT server you can integrate the monitoring data to virtually any Home Automation System. I use Home Assistant to automate off peak battery charging (using Force Charge) and can also enable and disable the charging and discharging.
The device itself no longer requires internet as the NTP Servers are now configurable, the web browser accessing this device does need internet access as the framework for the web page is loaded from a Content Delivery Network.
- Setup from a browser, flash to your ESP32 device then go to http://192.168.4.1 and connect it to your wifi, once connected go to http://diy-batterybms.local or it's IP address to configure all settings.
- NEW: Improved WiFi Setup Experience:
- WebSocket-based WiFi network scanning with automatic background refresh
- Networks sorted by signal strength for easier selection
- Duplicate networks filtered (strongest signal retained)
- Preserved saved SSID selection across scans
- WiFi configuration requires explicit save (manual save button for SSID, password, and mDNS hostname)
- Listen to VE.Direct messages and publish some of the information to a MQTT broker
The MQTT Topic is fully configurable. - Home Assistant MQTT Discovery - Automatically creates all sensors and switches in Home Assistant with no manual configuration required
- Supports MQTT Commands to enable and disable charge/discharging of an inverter, force charge the batteries to be able to charge over night at off peak rates. See the home assistant file for the commands and config (optional - discovery creates these automatically).
- Supports single MQTT server
- OTA (Over The Air Update)
use your browser and go to http://IPADDRESS/update and upload the lastest binary - please note the donation button does not donate to me. - LCD Screen Support (LCD 20x4 via I2C)
- Configurable NTP Server - This is for a future feature.
- Voltage Limited Charging, automatically reducing charge current to keep the voltage stable
The device now supports MQTT Discovery which automatically creates all entities when connected:
- Sensors: Battery SOC (%), Voltage (V), Current (A), Charge/Discharge Current Limits, Free Heap
- Binary Sensors: Charge/Discharge/Force Charge status indicators
- Switches: Charge Enable, Discharge Enable, Force Charge, SOC Trick Enable, Request Flags Enable
- Number Controls: Charge Voltage, Charge Current (with 0.1 precision)
- All entities are grouped under one "DIY Battery BMS" device
- No manual YAML configuration required (HomeAssistant.yaml is now optional for reference only)
- Discovery messages published automatically on MQTT connect
Protocol Control Features:
- SOC Trick Enable: Sends 1/10 of the actual SOC to trick the inverter into force charging
- Request Flags Enable: Controls charge/discharge request flags sent to inverter (allows different ways to control inverter response)
- MQTT to CAN BUS support, use esphome BMS intgrations to feed the data in and send to the inverter.
- Multi Inverter support
- OneWire temperature sensors for charge control
- Temperature monitoring of batteries and inverter to run heaters and fans.
- DiyBatteryBMS is only listening to messages of the VE.Direct device
It understands only the "ASCII" part of the protocol that is only good to receive a set of values. You can't request any special data or change any parameters of the VE.Direct device.
See the Wiki page
esp32dev, esp32plus, lilygo CAN485, ESP32-S3 with built-in CAN (TWAI).
Please use the recommended hardware, as a personal project it's difficult to support other configurations.
NEW: ESP32-S3 support with built-in CAN controller (TWAI) is now available.
- CAN_BUS_CS_PIN: 2
- CAN0_INT: 22
- VEDIRECT_RX: 33
- VEDIRECT_TX: 32
- CAN_BUS_CS_PIN: 5
- CAN0_INT: 13
- VEDIRECT_RX: 33
- VEDIRECT_TX: 32
- CAN_TX_PIN: 27
- CAN_RX_PIN: 26
- CAN_EN_PIN: 23
- VEDIRECT_RX: 33
- VEDIRECT_TX: 32
- CAN_TX_PIN: 27
- CAN_RX_PIN: 26
- CAN_EN_PIN: 23
- VEDIRECT_RX: 33
- VEDIRECT_TX: 32
- CAN_TX_PIN: 6
- CAN_RX_PIN: 7
- CAN_EN_PIN: 5
- VEDIRECT_RX: 21
- VEDIRECT_TX: 20
Note: These PINs can be configured through the web interface after flashing. The forbidden GPIO lists for each environment prevent selection of pins that should not be used.
Links:
esp32dev https://www.amazon.co.uk/gp/product/B0C9THDPXP/
esp32plus https://www.amazon.co.uk/dp/B0BHZ8H6LM
Lilygo CAN485 https://www.aliexpress.com/item/1005003624034092.html
LCD https://www.amazon.co.uk/dp/B07V5K3ZVB
Isolated CAN Bus Adapter https://www.amazon.co.uk/Coolwell-Isolated-Expansion-Raspberry-SN65HVD230/dp/B0C7VX6G6P
Non-Isolated Adapter - Does work and cheaper but can be blown if not careful. https://www.amazon.co.uk/AZDelivery-MCP2515-Receiver-Development-Compatible/dp/B086TXSFD8/
Victron Smart Shunt https://www.amazon.co.uk/Victron-Energy-SmartShunt-Battery-Bluetooth/dp/B0856PHNLX
I WILL NOT BE HELD LIABLE FOR ANY DAMAGE THAT YOU DO TO YOU, ONE OF YOUR DEVICES, BURN YOUR HOUSE DOWN, ETC. A CERTAIN LEVEL OF KNOWLEDGE IS EXPECTED, LIKE HOW TO WIRE THINGS AND PROGRAM THE SOFTWARE TO YOUR DEVICE.
