mk3:hvrelaywirring []

Dies ist eine alte Version des Dokuments!

High Voltage Relay Wiring – with Precharge

⚠️ **Disclaimer – Safety First!**
The wiring diagrams and connection examples provided here are **suggestions only**  and may not
cover all edge cases or safety requirements.
All high-voltage components must be installed and verified by a **qualified electrician**  or professional installer.
Incorrect wiring or misuse can lead to **severe damage, fire, or personal injury**.
The manufacturer assumes **no liability**  for damages resulting from improper installation or handling.

Below is the recommended HV wiring setup for systems using 3 relays and precharge functionality:

🧩 Components:

HV Battery: Provides the main power
HV Fuse: Protects the system from overcurrent
HV Relays (3 total):
- Precharge Relay: Connects via precharge resistor to slowly charge input capacitors
- Positive Relay: Main high-side connection to the load
- Negative Relay: Switches the low side (Battery -)
Precharge Resistor: Limits inrush current when first connecting to the inverter
Current Shunt: Measures total current flow
Inverter / Load: Final consumer of the HV power
Chassis connection (E pin): Must be connected to battery chassis – ideally with 2 separate wires

🔌 BMS HV Connector Pins:

B+ / B-: Connect directly to the battery
O+ / O-: Connected after the relays, represents the output side
E: Earth/Chassis connection

⚠️ Important: The precharge path must always lead through the shunt to ensure current measurement during precharge. The positive and negative relays must remain open during precharge phase and close only after precharge completes.

👉 This wiring ensures proper current monitoring and safe soft-start of the system.

Relay Control

The GRNbms MK3 directly controls all three HV relays using integrated 12 V outputs.
Each relay is connected via its dedicated connector:

HV Relay Positive
HV Relay Negative
HV Relay Precharge

Requirements:

Relays must have a 12 V coil
No external power supply is needed – the BMS provides the 12 V directly
Each output is internally protected and current-limited

✅ Just plug in your relays – the BMS handles power and timing automatically