Solar Energy Manager for ESP32 (SEM.32)

SEM.32 (Solar Energy Manager 32) based on ESP32 controller, Soyosource Inverter, Huawei r4850g2 power supply, JK-BMS and 48V battery. It helps You to maximize the usage of self generated solar power.

Main features:

• control of inverter to minimize power usage out of the grid (over RS485)
• control of charger to maximize own usage of solar power (over CAN-bus)
• adjustable power thresholds
• optional manual control of charging power
• optional dynamic load calculation to reduce wear of battery due to low chage status
• charge current limitation
• access to JK-BMS data (over RS485)
• new web GUI
• wifi configuration portal
• MQTT client
• scalable code for new features
• CAN dbc file for the charger
• runs ESP32 boards with RS485+CAN shield
• runs on ESP32 and on the BSC-Hardware

Web GUI

Hardware components:

• Inverter:

  • Type: GNT 1200LIM 48
  • MAX: Const. Power: 800W (1200W solar operation)

• Charger:

  • Type: Huawei R4850G2

• BMS:

  • Type: JK-BD6A20S8P
  • Software V.: V10.XY

• Battery cells:

  • Type: EVE LF90 (3,2V 90AH, Nominal)
  • Datasheet No.: LF90-73103
  • Cut off Voltage: 3.65V/2.5V
  • Std. charge/Discharge: 1.0C

• Power Meter:

  • Type: Tasmota based smart meter from Hitchi

• Controller:

  • ESPRESSIF ESP32-WROOM-32U DEVKITC(with ext. Antenna)

• CAN interface:

  • Driver IC: SN65HVD230

• RS485 Serial interface:

  • Driver IC: Max485 CSA (2 pcs. for BMS and Inverter)

• 0.96 inch OLED IIC 128x64 Display:

  • Driver: SSD1306
  • I2C Addr.: 0x3C

• Temperature Sensors:

  • 1-Wire
  • Type: DS18B20 waterproof

External connectors:

USB upper:

Pin 2 (RXD/D-) Output A Max 485 USB Driver for inverter, Inverter Input A+

Pin 3 (TXD/D+) Output B Max 485 USB Driver for inverter, Inverter Input B-

USB Lower:

Pin 2 (RXD/D-) CAN L

Pin 3 (TXD/D+) CAN H

RJ45:

Pin 1 (Pair 3) Output A Max 485 USB Driver for BMS, BMS Input A+

Pin 2 (Pair 3) Output B Max 485 USB Driver for BMS, BMS Input B-

6 pin connector:

Pin1 GPIO26 Temp Sensor

Pin2 Ground

Pin3 +3V3

Pin4 NC

Pin5 NC

Pin6 NC

Pinning Controller

GPIO	Function	Application	Driver
GPIO00	Boot	Push Burron 1
GPIO01
GPIO02
GPIO03
GPIO04	CAN RX	Charger	SN65HVD230
GPIO05	CAN TX	Charger	SN65HVD230
GPIO06
GPIO07
GPIO08
GPIO09
GPIO10
GPIO11
GPIO12	LED	Blue, Charging
GPIO13	LED	Green, Discharging
GPIO14	LED	Yellow, Standby
GPIO15	LED	Red, ERROR
GPIO16	U2RXD	Inverter	Max485 CSA
GPIO17	U2TxD	Inverter	Max485 CSA
GPIO18	RS485_EN	Chip enable, Inverter	Max485 CSA
GPIO19
GPIO21	I2C SDA1	Display SSD1306	Address: 0x3C
GPIO22	I2C SLC1	Display SSD1306	Address: 0x3C
GPIO23
GPIO25
GPIO26	DAT	Temp. Sensors	DS18B20; inc. 4K7 pull up
GPIO27
GPIO32	RS485 RxD	BMS	Max485 CSA
GPIO33	RS485 TxD	BMS	Max485 CSA
GPIO34	RS485_EN	BMS	Max485 CSA
GPIO35	Dig_input	Push Button 3
GPIO36	Dig_input	Push Button 2
GPIO39	LED	auxiliary

Information:

Power Equation for the whole house: $\ ActGridPower + ActBatPower + SolProd = Used Power$

JSON help: https://arduinojson.org/v6/assistant/#/step1

ESP32 infos: https://www.upesy.com/blogs/tutorials/how-to-connect-wifi-acces-point-with-esp32

BSC (Battery Safety Controller) homepage: https://github.com/shining-man/bsc_fw

JK-BMS Protocol: jblance/mpp-solar#112 (comment)

JK-BMS collection of NEEY: https://github.com/NEEY-electronic/JK/tree/JK-BMS

Known issues:

Solution for Littlefs error: pio pkg update -g -p espressif32