The GRNbms MK3 supports both High Voltage (HV) and Low Voltage (LV) operation.

• Connect 12 V to the „Jump Start“ connector
• This powers the BMS directly for low-voltage applications or setup/configuration

👉 Details about relay and output wiring can be found here

• For high-voltage setups, connect the BMS using the dedicated HV connectors

HV POS Connector:

• B+ → Connect directly to Battery Positive
• O+ → Output (post-relay) – not required for power supply

HV NEG Connector:

• B- → Connect directly to Battery Negative
• O- → Output (post-relay) – not required for power supply

✅ To power the BMS: only B+ and B- are needed

⚠️ Valid voltage range: 150 V – 1200 V DC Operating the BMS outside this range may cause malfunction or damage.

Additionally, for safety and EMI compliance:

• Connect the battery chassis to the E pin on the CHASSIS connector
• Use a dual connection if possible for redundancy

👉 Details about relay and output wiring can be found here

An internet connection is required for the initial setup and activation of your BMS.

📝 Note: A GRNbms.de account is required to complete the setup.
You can create one during the initial configuration or in advance here.

• Connect the BMS (ETHERNET 1 Connector) to your local network using a standard RJ45 Ethernet cable
• The BMS will automatically obtain an IP address via DHCP (from your router)

If no Ethernet is available, the BMS can create a WiFi access point:

• Plug in a compatible USB WiFi stickbefore power-on
• ✅ Must be a supported chip – see compatible WiFi sticks list

The BMS will create a hotspot:

• SSID:GRNbms_MK3_AP
• Password:0123456789
• IP Address:192.168.4.1

Connect to the hotspot and open http://192.168.4.1to start setup.

Once connected, try opening one of the following in your browser:

• http://grnbmsmk3/
• http://grnbmsmk3.local/

💡 These names work only if your router supports mDNS or local hostname resolution.

No problem – just visit GRNbms.de
There you can see all BMS devices in your local network.

When you access the BMS interface for the first time, a guided setup will begin automatically.

If no internet connection is available, the BMS will first ask you to connect it to the internet (via Ethernet or WLAN).

Once online, you will be prompted to log in with your GRNbms.de account.

🧑‍💼 The first user to log in will automatically become the owner of this BMS system.

If a firmware update is available, the BMS will guide you through the update process before proceeding.

After completing all steps, you will be redirected to the main overview page, where you can continue configuration.

🔐 To make further changes, you need to log in again via the login button in the top right corner of the web interface.