JK‐PB Inverter BMS

Connecting JK-PB* Inverter BMS

These models must be configured to use Protocol 000 - 4G-GPS Remote module Common protocol V4.2 as UART1 Protocol using the Bluetooth App or Windows Software.

RJ45 Connector

Use the leftmost RJ45 connector, which is pinned as follows:

Pins	Function
1, 8	RS485-B
2, 7	RS485-A
3, 6	GND

Wiring

Two wiring methods are supported. The battery.rx and battery.tx pins must be defined in the pin mapping for both methods. When using the RS-485 Transceiver on MCU interface type, battery.rxen and battery.txen pins must also be defined. See the device profile documentation for more details.

RS485 with external Transceiver and UART-TTL

The wiring can be completed using an external RS485 to UART-TTL converter board. Search for DEBO TTL-RS485 on reichelt.de for an example. For the UART receive pin on the ESP32 an input-only pin may be used.

           RS485           RS485-TTL
┌────────┐       ┌────────┐         ┌───────┐
│        │<A---A>│        │<TX---RX>│       │
│ JK-BMS │<B---B>│ RS485  │<RX---TX>│ ESP32 │
│        │<-GND->│ to 3V3 │<--GND-->│       │
│        │       │        │<--3V3-->│       │
└────────┘       └────────┘         └───────┘

Use the TTL-UART on MCU interface type in the OpenDTU-OnBattery settings for this setup. The ESP32 will talk UART to the converter board. The RS485 transceiver is transparent to the ESP32. That also means it has no explicit control over the transmitter or receiver. That in turn might cause the ESP32 to read its own data (only for bad converter boards).

RS485 with Transceiver

The wiring can be completed using only an RS485 transceiver chip that is connected to the ESP32 directly. This is the case for the OpenDTU-FUSION board, where an ISL3178E transceiver is in use. There are also breakout-boards available that only have a RS485 transceiver (search for MAX485 Module).

This setup requires four pins on the ESP32: Two for data (one input, one output), one that controls the receiver, and another that controls the transmitter. The latter two are outputs.

            RS485
              ┌──────────────────────────────┐
┌────────┐    │    ┌───────────┐   ┌───────┐ │
│        │<A--+--A>│A      RXEN│<->│15     │ │
│ JK-BMS │<B--+--B>│B        RX│<->│16 ESP │ │
│        │    │    │       TXEN│<->│46  32 │ │
│        │<-->│GND │ISL3178E EN│<->│45     │ │
└────────┘    │    └───────────┘   └───────┘ │
              │       OpenDTU Fusion v2      │
              └──────────────────────────────┘

Use the RS485-Transceiver on MCU interface type in the OpenDTU-OnBattery settings for this setup.