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.

Connect the BMS to your local network using a standard RJ45 Ethernet cable

The BMS will automatically obtain an IP address via DHCP (from your router)

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

Follow the guided setup instructions