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

• 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.