Marstek Venus E - ESPHome Configuration

High-performance ESPHome configuration for Marstek Venus E battery integration via Modbus RS485

Monitor and control your Marstek Venus E plug-in battery (5.12 kWh) using ESPHome and the LilyGO T-CAN485 board. This configuration provides real-time battery metrics, runtime estimates, energy efficiency tracking, and full control over charging/discharging modes.

✨ Features

Monitoring & Control

Real-time Battery Metrics: SOC, voltage, current, power, temperature with cell-level monitoring
Runtime Estimation: Dynamic time-to-full/empty calculation based on power flow
Energy Tracking: Daily, monthly, and lifetime charge/discharge statistics
Work Mode Control: Manual, Anti-feed, AI modes with forcible charge/discharge
Power Management: Adjustable limits (0-2500W), SOC targets (12-100%), backup function
24 Warning Sensors: Real-time alerts for grid, battery, temperature, and communication issues

ESPHome Integration

Built-in Web Server: Access battery data directly via browser (no Home Assistant required)
OTA Updates: Wireless firmware updates via ESPHome dashboard or web interface
Status LED Feedback: Visual system state via onboard WS2812 LED
System Diagnostics: WiFi/BT/Cloud status, software versions, connection monitoring

Home Assistant Ready

Automatic Discovery: Zero-config integration via ESPHome API
Complete Dashboard: Ready-to-use Lovelace YAML with battery metrics and controls
Efficiency Templates: Custom sensors for monthly/total efficiency and round-trip loss tracking
Energy Dashboard Compatible: Integrates with HA energy management

Optimized Performance

Event-driven Architecture: 3-second response times for critical sensors
Modbus Optimization: 57% less bus traffic through register batching
Network Efficiency: 56% fewer API calls, 35-40% reduced traffic
Memory Optimized: 22-25 KB less RAM usage, 20 KB smaller firmware

⚡ Performance

Original vs. Optimized Configuration

Performance Metric	Original Config	This Config	Improvement
API Updates	~250/min	~110/min	-56% ⚡
Battery Power Response	15 seconds	1 second	93% faster ⚡
Modbus Bus Requests	~35 per cycle	~15 per cycle	-57% ⚡
Battery Capacity Update	120s polling	3s event-driven	40x faster ⚡
RAM Usage	Baseline	-22 to -25 KB	Optimized 💾
Network Traffic	100%	60-65%	-35 to -40% 📡
Firmware Size	Baseline	-20 KB	Smaller 💿
WiFi Throughput	Standard	+20-30% faster	Enhanced 📶
Boot Time	2-3 seconds	1.5-2 seconds	Faster 🚀
Network Latency	Baseline	-15 to -25ms	Lower ⚡

Key Optimizations

🔧 Modbus Efficiency

Register batching reduces 7 blocks from 24 requests to 7 requests
Smart polling with skip_updates for slow-changing values
Event-driven updates instead of fixed intervals

💾 Memory & Performance

22-25 KB less RAM usage through optimizations
20 KB smaller firmware size
Faster boot times and reduced CPU load

📡 Network Optimization

56% fewer API calls through intelligent batching
35-40% less network traffic via throttling
20-30% WiFi throughput increase with AMPDU

⚡ Response Times

Battery Power: 15s → 1s (instant response)
Battery Capacity: 120s → 3s (event-based)
Sensor updates: Real-time with throttling

Result: A highly optimized configuration that's faster, more efficient, and more reliable than the original while maintaining full functionality.

📸 Screenshots

ESPHome Web Interface

Cell information, AC/DC metrics, and energy statistics

Network status and control settings

System diagnostics and warning sensors

Home Assistant Dashboard

lovelace-solar_marstekbattery screenshot

Complete Lovelace dashboard with battery metrics, controls, and energy flow

🛠️ Hardware Requirements

Required Hardware

Component	Model	Where to Buy
ESP32 Board	LilyGO T-CAN485	LilyGO Official Store
Battery	Marstek Venus E (5.12 kWh)	Marstek
Cable	RS485 cable (2-wire)	Included with Marstek (Weipu SP17 connector) or use standard Modbus cable

About the Cable

The Marstek Venus E battery includes a Weipu SP17 5-pin connector with RS485 terminals. You can:

Use the included cable directly
Create a custom cable with Weipu SP17 male connector
Use any standard RS485 cable with A+/B- terminals

🚀 Quick Start

1. Flash ESPHome to LilyGO

See INSTALL ESPhome on LilyGo.md for detailed flashing instructions.

2. Download Configuration

Download the latest configuration from the releases page:

Download Latest Config →

Click on Marstek-Lilygo-ESPHome-Config.yaml under Assets to download.

3. Generate API Encryption Key

Generate a secure encryption key using OpenSSL:

openssl rand -base64 32

Or use the ESPHome dashboard to generate one automatically:

Visit ESPHome API Documentation
Scroll down to "Encryption Key" section
Click the generate button

4. Customize Secrets

Create a secrets.yaml file:

# WiFi Credentials
wifi_ssid: "YourSSID"
wifi_password: "YourPassword"

# API Encryption Key (generated above)
api_encryption_key: "your-32-char-base64-key-here"

# OTA Password (choose your own)
ota_password: "your-secure-ota-password"

5. Validate & Flash Configuration

First, compile and validate the configuration:

esphome compile Marstek-Lilygo-ESPHome-Config.yaml

If compilation succeeds, flash the device:

esphome run Marstek-Lilygo-ESPHome-Config.yaml

📦 Installation

ESPHome Installation via PowerShell/Terminal

Install with pip (Recommended)

pip3 install esphome --upgrade

Verify Installation

esphome version

Detailed Installation Methods

For step-by-step flashing instructions including USB drivers, bootloader mode, and troubleshooting, see:

INSTALL ESPhome on LilyGo.md

This guide includes:

Driver installation for Windows/Mac/Linux
Entering bootloader mode on LilyGO T-CAN485
First-time USB flashing
Common flashing errors and solutions

Using the Configuration

Download Configuration

Visit Releases and download Marstek-Lilygo-ESPHome-Config.yaml
Generate API Key
```
openssl rand -base64 32
```
Create Secrets File

Create secrets.yaml in the same folder with your WiFi credentials and generated API key.

Compile Configuration

esphome compile Marstek-Lilygo-ESPHome-Config.yaml

Initial Flash (USB)

esphome run Marstek-Lilygo-ESPHome-Config.yaml

🏠 Home Assistant Integration

Automatic Discovery

ESPHome devices are automatically discovered in Home Assistant via the ESPHome integration.

Steps:

Home Assistant will show a notification: "New device discovered"
Click "Configure"
Enter your api_encryption_key from secrets.yaml
Device is ready to use!

Manual Addition

If auto-discovery doesn't work:

Navigate to Settings → Devices & Services
Click + Add Integration
Search for ESPHome
Enter:
- Host: 192.168.178.160 (or your configured IP)
- Encryption Key: Your api_encryption_key from secrets.yaml

Dashboard Import

Import the included dashboard for a complete UI:

File: Home Assistant Marstek Dashboard.yaml

Copy the YAML content
In Home Assistant: Settings → Dashboards → Edit Dashboard
Click ⋮ (three dots) → Raw configuration editor
Paste the YAML content
Save

Dashboard Features:

Real-time battery metrics and status
Runtime estimation display
Charge/discharge controls
Warning indicators with color coding
Energy statistics (daily, monthly, total)
Work mode selection
Power limit adjusters

Efficiency Templates

The included Home Assistant Template adds advanced efficiency tracking:

File: Home Assistant Template.yaml

Add to your configuration.yaml:

template: !include_dir_merge_list templates/

Create templates/marstek_efficiency.yaml and paste the template content.

New Sensors:

Monthly Efficiency (%): (Monthly Discharge / Monthly Charge) × 100
Total Efficiency (%): (Total Discharge / Total Charge) × 100
Shows energy lost during charge/discharge cycles
Useful for battery health monitoring

📊 Sensors & Entities

Battery Monitoring (8 sensors)

Voltage, Current, Power, State of Charge (%)
Remaining Capacity (kWh), Total Energy (kWh)
Max/Min Cell Voltage, Cell Voltage Difference

Runtime & Status (2 sensors)

Runtime Estimate - "Full in: 2h 30min" / "Empty in: 1h 45min" / "Standby"
Inverter State - Sleep/Standby/Charge/Discharge/Fault/Idle

AC Grid (3 sensors)

AC Voltage, Current, Power

Energy Statistics (6 sensors)

Total Charging/Discharging Energy (kWh)
Daily Charging/Discharging (kWh)
Monthly Charging/Discharging (kWh)

Temperature (5 sensors)

Internal Temperature, MOS1/MOS2 Temperature
Max/Min Cell Temperature

System Info (7 sensors)

Software/Firmware/BMS Version
ESPHome Version, IP Address, SSID
WiFi Signal Strength

Controls (11 entities)

RS485 Control Mode, Work Mode Selection
Forcible Charge/Discharge with Power Limits
Backup Function, SOC Charge Target
Max Charge/Discharge Power Settings
Charging/Discharging Cutoff Capacity

Warning Sensors (24 binary sensors)

Comprehensive monitoring for grid issues, battery protection, temperature alerts, and communication status.

🔗 Credits & Resources

Special Thanks

💡 @Superduper1969 - Original MarstekVenus-LilygoRS485 implementation
https://github.com/Superduper1969/MarstekVenus-LilygoRS485/tree/main

🧰 @scruysberghs - ha-marstek-venus integration
https://github.com/scruysberghs/ha-marstek-venus

Documentation

📘 Modbus Register Documentation - Marstek Venus C/E Protocol
https://duravolt.nl/wp-content/uploads/Duravolt-Plug-in-Battery-Modbus.pdf

📘 LilyGo T-CAN485 Documentation - Hardware specs and pinout
https://github.com/Xinyuan-LilyGO/T-CAN485

📑 Modbus Register Spreadsheet - Complete register overview
Google Spreadsheet - Modbus Registers

Community

💬 Tweakers Forum - Dutch community discussions

Official Links

📝 Latest Release

See the complete changelog and download the latest version:

Latest Release →

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

Name		Name	Last commit message	Last commit date
Latest commit History 61 Commits
Home Assistant Marstek Dashboard.yaml		Home Assistant Marstek Dashboard.yaml
Home Assistant Template.yaml		Home Assistant Template.yaml
INSTALL ESPhome on LilyGo.md		INSTALL ESPhome on LilyGo.md
Marstek Lilygo ESPHome Config.yaml		Marstek Lilygo ESPHome Config.yaml
README.md		README.md
www.js		www.js

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