Marstek Windows Overlay

A transparent, always-on-top Windows overlay that shows Marstek battery SOC via the local UDP JSON-RPC API.

Prerequisites

• Node.js 18+ (includes npm)
• Windows 10/11 on the same network as the Marstek device

Development

npm install
npm run dev

Build

npm run build
npm run package

Settings

Open the Settings panel in the overlay to change:

• Device IP (default 192.168.50.120)
• UDP port (default 30000, recommended range 49152–65535 per Marstek docs)
• Polling interval in ms (default 5000 for testing)

Marstek Local API

The app uses the local UDP JSON-RPC endpoint described in the Marstek Open API PDF and calls:

{"id":1,"method":"Bat.GetStatus","params":{"id":0}}

SOC is read from response.result.soc.

Troubleshooting

• UDP timeout: ensure the PC and Marstek device are on the same subnet.
• Windows firewall: allow UDP traffic for the app.
• Wrong IP/port: verify your Marstek device LAN IP and port in its local API settings.

Click-through

Use the Click-through button to toggle mouse pass-through. When ON, the overlay ignores mouse events so you can interact with windows underneath.