How to Connect JK BMS to a Victron Inverter
JK BMS is widely used in DIY LiFePO4 battery systems because it combines battery protection, active balancing and inverter communication in one system.
For Victron users, the JK BMS can communicate with a Victron system through CAN bus, allowing the inverter system to receive important battery information such as:
- Battery SOC
- Battery voltage
- Charge current limit
- Discharge current limit
- Charge voltage limit
- BMS alarms and protection status
When CAN communication is working correctly, the Victron system can adjust charging and discharging according to the limits sent by the BMS instead of relying only on manually configured voltage settings.
Important: The exact menu names, CAN protocol number and RJ45 pinout can vary between JK BMS firmware and hardware versions. Always check the settings and port definition of your specific BMS before connecting the communication cable.
What You Need
Before starting, prepare:
- A JK inverter-compatible BMS, such as a JK V19 / JK PB series BMS
- A compatible Victron inverter/charger
- A Victron GX device, such as Cerbo GX, or a Victron product with integrated GX functionality
- Correct CAN communication cable
- JK BMS mobile app or PC software
In a managed lithium battery system, the GX device acts as the communication bridge between the battery BMS and the Victron system. Victron normally uses its BMS-CAN interface at 500 kbit/s for compatible managed lithium batteries.
Step 1: Select the Victron Protocol in JK BMS
Open the JK BMS App or JK PC software and locate the inverter communication settings.
For JK BMS versions that provide the following option, select:
CAN Protocol: 004 – Victron_CANbus
The exact protocol number may differ depending on firmware, so the important point is to select the protocol specifically labeled Victron or Victron CAN.
The reference JK installation configuration commonly uses the Victron CANbus protocol for communication with the GX system.
After changing the protocol, we recommend restarting the BMS before testing communication.
Step 2: Connect the JK BMS CAN Port to the Victron GX
Connect:
JK BMS CAN Port → Victron BMS-CAN / configured VE.Can Port
Do not connect the communication cable to the JK RS485 port by mistake.
The CAN and RS485 ports may both use RJ45 connectors, but their electrical definitions and functions are different.
Victron CAN Speed
For the common JK Victron CAN configuration, set the GX CAN interface to:
BMS-Can — 500 kbit/s
On configurable Victron GX devices, the setting can normally be found under the CAN port configuration menu.
For example:
Settings → Connectivity / Services → VE.Can Port → CAN-bus Profile
Choose the appropriate BMS-Can 500 kbit/s profile.
On the original Cerbo GX, the dedicated BMS-Can port operates at 500 kbit/s. On newer GX devices such as the Cerbo GX MK2, the VE.Can ports can be configured for different CAN profiles.
Step 3: Choose the Correct Victron CAN Cable
This is one of the most important parts of the installation.
Victron provides two versions of the VE.Can to CAN-bus BMS cable:
Victron Type A
| Function | Victron Side | Battery Side |
|---|---|---|
| GND | Pin 3 | Pin 6 |
| CAN-L | Pin 8 | Pin 5 |
| CAN-H | Pin 7 | Pin 4 |
Victron Type B
| Function | Victron Side | Battery Side |
|---|---|---|
| GND | Pin 3 | Pin 2 |
| CAN-L | Pin 8 | Pin 5 |
| CAN-H | Pin 7 | Pin 4 |
These are the official Victron pin assignments.
Type A or Type B for JK BMS?
Do not assume that every JK BMS uses the same cable.
Different JK BMS hardware versions may have different RJ45 CAN port definitions. Some installations operate with Type A, while others use Type B.
Therefore, before ordering or making a cable:
Check the CAN pinout printed in your JK BMS manual or confirm it with the battery supplier.
This simple check can prevent most CAN communication problems.
Step 4: Check Whether Victron Detects the Battery
After connecting the CAN cable:
- Turn on the battery.
- Turn on the GX device and Victron system.
- Open the GX Device List.
- Check whether the battery appears.
When communication is successful, the Victron interface should normally show battery information such as:
SOC
Battery Voltage
Battery Current
Charge Current Limit
Discharge Current Limit
Charge Voltage Limit
Victron uses CAN communication from compatible managed batteries to receive charge/discharge limits, SOC and battery status.
If these values are changing correctly, communication has been established.
Connecting Multiple JK BMS Batteries in Parallel
A multi-battery system normally uses a Master + Slave communication structure.
The basic communication architecture is:
Slave Batteries → RS485 → Master Battery → CAN → Victron GX
Only the Master BMS communicates directly with Victron through CAN.
For JK systems using the address structure shown in the common V19 configuration, the addresses may look like:
| Battery | Address |
|---|---|
| Master | 0000 |
| Slave 1 | 1000 |
| Slave 2 | 0100 |
| Slave 3 | 1100 |
The exact DIP-switch sequence should always be checked against your JK BMS version.
The reference JK configuration uses address 0000 for the master, with additional batteries connected to the master through RS485.
Communication Structure
Battery 4 ─┐
Battery 3 ─┤
Battery 2 ─┤ RS485 → Master JK BMS → CAN → Victron GX
Battery 1 ─┘
Victron will usually display the parallel system as one combined battery bank, rather than showing every battery as a separate battery entry.
JK BMS Not Communicating With Victron?
If the battery does not appear in Victron, check these items first.
1. Wrong CAN Protocol
Open the JK App and make sure the selected inverter protocol is Victron CAN.
Do not use Pylontech, Deye, Growatt or another CAN protocol unless your particular system specifically requires it.
2. Wrong RJ45 Port
Make sure the cable is connected to the CAN port, not RS485.
Some JK documentation and hardware revisions can make the port arrangement confusing, so always check the marking on your specific BMS. Victron community users have reported cases where identifying the correct JK RJ45 CAN connector was essential to establishing communication.
3. Wrong CAN Baud Rate
For this configuration, the Victron CAN interface should normally use:
500 kbit/s
Using a VE.Can port still configured to its normal 250 kbit/s profile will prevent communication with a BMS expecting 500 kbit/s. Victron documents these as different CAN profiles.
4. Wrong Type A / Type B Cable
This is a very common problem.
An RJ45 connector physically fitting into the socket does not mean the pinout is correct.
Check:
CAN-H
CAN-L
GND
against the JK BMS pinout before replacing the BMS or GX device.
5. Master/Slave Address Is Incorrect
For parallel batteries:
- Only one battery should be configured as Master.
- Each Slave must have a unique address.
- RS485 communication between the batteries must be connected correctly.
- CAN to Victron should come from the Master battery.
6. Restart the System
After changing CAN protocol or address settings:
Power off the BMS → wait several seconds → restart the battery and GX system.
Some settings may not become active until the BMS has restarted.
CAN Communication vs. Voltage Control
A LiFePO4 battery can technically operate with an inverter using manually configured charge and discharge voltages without CAN communication.
However, CAN communication offers much better system integration.
Instead of the inverter making decisions based only on battery voltage, the JK BMS can dynamically communicate information such as:
“Reduce charging current.”
“Stop charging.”
“Reduce discharge current.”
“Stop discharging.”
This is especially useful for larger LiFePO4 storage systems and multiple batteries connected in parallel.
Final Checklist
Before powering up the complete system, confirm:
✓ JK BMS Victron CAN protocol selected
✓ Correct CAN port used
✓ Victron CAN profile set to 500 kbit/s
✓ Type A / Type B cable pinout verified
✓ Master battery address configured correctly
✓ Slave batteries have unique addresses
✓ RS485 connected between parallel batteries
✓ CAN connected only between Master BMS and Victron GX
✓ Battery data appears correctly in the GX Device List
Once these items are correct, the JK BMS and Victron system should be able to exchange battery information through CAN communication.
Need Help Connecting Your JK BMS to Victron?
Deligreen Power supplies JK BMS-based LiFePO4 battery systems and DIY battery kits for residential and off-grid energy storage.
If you are unsure which communication cable or protocol should be used, send us:
1. Your JK BMS model
2. A photo of the BMS communication ports
3. Your Victron inverter / GX model
Our technical team can help you confirm the correct communication configuration before installation.
