===== GRNbms MK3 Mini – Wiring & Pinout =====

This page provides an overview of the wiring and pinout for the **GRNbms MK3 Mini**. Please refer to the respective Wiki pages for detailed information about [[:mk3:canbus|CAN]], [[:mk3:modbus|RS485, and Modbus]] communication.

⚠️ ''Power over Ethernet (PoE) is not supported for GRN products and must not be used under any circumstances. The use of PoE with GRN products is strictly prohibited. Any non-compliance with this requirement may result in damage to the equipment. The company assumes no liability for any damages, malfunctions, or consequential losses arising from such misuse.''
==== Power Supply ====

  * **Recommended input voltage:**  11 – 14 V DC
  * Power should be supplied via the designated power input pins (see pinout table below).

==== GRNcmu Connection ====

  * The **RJ45 port**  is directly compatible with a standard Ethernet cable.
  * Designed for seamless plug-and-play connection with the **GRNcmu Multi Mini**  module.

==== Fan Connector ====

  * Compatible with standard **4-pin 12 V PC cooling fans**.
  * The GRNbms provides PWM control and tachometer feedback support.

==== RS232 Port ====

The RS232 port on the GRNbms MK3 Mini is **directly compatible with Victron’s VE.Direct protocol**, specifically for **reading current sensors (shunts)**.

  * Enables direct connection to Victron-compatible shunts without the need for converters.
  * Ideal for monitoring real-time current flow in systems using Victron infrastructure.

==== Display Connector ====

  * Ready to use with **[[:mk3:nextion|Nextion]] displays**.
  * Direct plug-in, no additional adapters required.

==== Connectors ====

1x 2.54-8P LCSC Part: C2927489 \\ 2x 2,54-2P LCSC Part: C2927483 \\ 3x 2,54-4P LCSC Part: C2927485 \\ 1x 2,54-3P LCSC Part: C2927484

==== Pinout Overview ====

**Supply & Relays**

|1|Supply GND|
|2|Supply 12V|
|3|COM connection of the emergency stop switch|
|4|NC connection of the emergency stop switch|
|5|Main Relay -|
|6|Main Relay +|
|7|Precharge Relay -|
|8|Precharge Relay +|

**5V Aux**

|1|GND|
|2|5V Output|

**RS232**

|1|RS485 A+|
|2|RS485 B-|

**Sensors**

|1|3.3V Output|
|2|Data|
|3|GND|

**GRNcmu RJ45**

|1|CAN2 High|
|2|CAN2 Low|
|3|12V CMU|
|4|GND|
|5|GND|
|6|12V CMU|
|7|12V CMU|
|8|GND|

**Inverter RJ45**

|1|GND|
|2|12V|
|3|-|
|4|12V|
|5|GND|
|6|-|
|7|CAN1 High|
|8|CAN1 Low|

**Inverter, CMU, Shunt - CAN**

|1|GND|
|2|Inverter / CMU / Shunt - 12V|
|3|Inverter / CMU / Shunt - CAN Low|
|4|Inverter / CMU / Shunt - CAN High|

**Display**

|1|5V|
|2|Display1 RX|
|3|Display1 TX|
|4|GND|

**FAN**

|1|GND|
|2|12V|
|3|Tacho|
|4|PWM|

**RS232**

|1|GND|
|2|RS232 1 TX|
|3|RS232 1 RX|
|4|12V|

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{{:mk3:mk3minipinout.png?nolink&800}}