After weeks of research and experimentation, I’m thrilled to share my success in integrating the KL8300-HV83G controller with the KL8-3H-FACE3 panel into Home Assistant using ESPHome and an ESP32. This achievement not only allows me to monitor my spa’s water temperature but also opens the door to a host of other automation possibilities. Here’s how I did it and what I learned along the way.
The Challenge
Initially, I faced significant hurdles due to the lack of public technical documentation for the KL8300 controller. Forums, GitHub repositories, and even Chinese sites provided little clarity. My journey began with voltage measurements and UART sniffing, which led me to suspect that the 8-pin connector on the KL8300 was a UART TTL 5V interface. However, early attempts to capture data were met with silence—no UART data was received, and my ESP32’s LED remained unblinking.
The Breakthrough
Persistence paid off. I realized that the controller might require a specific polling sequence or master-slave communication protocol. Drawing inspiration from the Balboa protocol, I experimented with framing data using 0x7E and adjusting baud rates. Finally, I struck gold—data began flowing into my ESPHome setup!
The Setup
Here’s a brief overview of my setup:
- ESP32 DevKit V1 with voltage divider to protect the RX input (5V → 3.3V)
- ESPHome 2025.4.1 configured to log raw UART frames in hexadecimal
- Custom scripts to parse and display the water temperature in Home Assistant
Lessons Learned
- Documentation Gaps Are Opportunities for Innovation: When official resources are scarce, the community becomes your greatest ally. Engaging with forums and open-source projects can lead to breakthroughs.
- Hardware Testing Is Essential: Without physically measuring voltages and testing pins, I wouldn’t have identified the UART interface.
- Protocol Reverse Engineering Requires Patience: Understanding proprietary protocols can be time-consuming, but tools like ESPHome and a willingness to experiment make it manageable.
- Community Collaboration Is Key: I’m grateful to the open-source community for their contributions and willingness to share knowledge. If you’re working on similar projects, consider collaborating to accelerate progress.
Looking Ahead
This success has inspired me to explore further automation possibilities, such as integrating pool heating and water treatment systems. I’m also considering sharing my findings in a GitHub repository to help others who might be tackling similar challenges.
A huge thank you to everyone who contributed insights and resources along the way. Your support made this achievement possible!
If you’re working on a similar project or have questions about my setup, feel free to reach out. Let’s continue to push the boundaries of smart home automation together!