To set the relay control mode, go to Battery → Relay Type in the sidebar.

This setting determines how the BMS handles relay logic based on your system voltage and wiring.

1. Onboard HV Isolation Test

Designed for high voltage systems

Activates the full 3-relay setup including precharge and isolation test

Matches the HV relay wiring described here

2. LV with Precharge

For low voltage systems (e.g. 12 V or 24 V setups)

Uses a simplified relay logic with optional precharge

⚠️ Make sure the selected mode matches your physical wiring, otherwise the system may not function correctly.

🔓 Each relay mode must be unlocked separately via grnbms.de.
Only the modes you've purchased will be available for selection.