BLUETOOTH CONNECTION

Download and install the JK BMS smartphone app, apple or android links below. This software will allow you to monitor and change settings and parameters on your BMS, this is the only app you will need in many cases

The first password is will ask you for is for bluetooth which is 1234.
The second password you might need is to change the settings in any way. It is 123456.

Inside this app you will find many settings. Which you will know if you are building your own pack.

Such as cell count = 16 (51.2v)
Capacity = 314 (ah)

We recommend these settings
Balance Start Voltage – – 3.4v-3.45v
This setting can be set anywhere from 3.37-3.5v,
The best setting is 3.45v for batteries that see high current charging, and 3.4v for low current charging in my experience.

I want to start balancing when the first cell is reaching the knee. allowing more time to move the current, not when its further up the knee, but when it first reaches the knee. This is unlikely to make any really different at high C rates. High C rates at high SOC, is very bad for the cells.
But that is another level of control that can be very difficult to implement. Though the new inverter BMS with current limiting and inverters that support control of that feature could and may control the current when the SOC is accurate.

Here are 2 screen shots of a 51.2v 16s with 314ah cells from 2024. You can use these settings if you would like. The default Lifepo4 profile button, when pressed will need a few settings changed. So please don’t push it unless you know all the other settings and you will need to put them in one by one.
(at this stage, this is the biggest problem with the BMS, as most others have been solved in the past few weeks).

Special Notes – If you find other users with different settings, it doesn’t mean anyone is wrong, there are no exact settings actually and they can be changed to suit your specific application, for example, the balance start voltage could be affected by high currents or high resistance and even low quality or low-grade cells. There are many reasons this could be adjusted. So please understand, there is no right or wrong, there is a spectrum of appropriate settings based on each user, and even then, it might need adjustment and may never work properly without increasingly complex programming and measurements that are basically impossible to make. Welcome to world of its not worth it the effort.

JK BMS MONITOR

PC Windows App – also for Firmware updates

Download the JK BMS MONITOR SOFTWARE > Link
This software is for both monitoring and changing settings on JK BMS, however it also allows you to flash a new firmware onto your JK BMS (a bit like the operating system). This process is technical and so we have a warning written for your own benefit.

To connect you must follow these instructions carefully.

FIRWARE UPDATE – DO NOT DO THIS UNLESS YOU HAVE TO DO THIS – TO FIX SOMETHING BROKEN

Connect to the BMS by Bluetooth
a) when connected to your battery and has power
b) go into the settings – enter password (123456)
c) look for the UART protocol selection
d) change it to the option 1 (JK BMS Modbus protocol)
e) remember this might need to be changed again if you are planning to communicate with an inverter in the future, the most reliable communication protocol has tradionally been the Pylontech protocol, try that if all else fails.

Your RS485 needs to be connected to the left RS485 port, the very first RJ45 socket, which is also for inverter communications

“Updating firmware can improve your device’s performance and or security, but it also carries risks. Ensure you are using the correct firmware version for your specific model, as installing incompatible firmware can permanently damage your device.
Its generally recommeneded to back up your previous firmware and take note of all your settings in the current BMS software
Before proceeding and follow the manufacturer’s instructions carefully. Avoid interrupting the update process, as power loss or disconnection during the update can render your device unusable. Only download firmware from trusted sources to prevent malware infection. Proceed with caution”

Firmware files

WARNING!! WARNING!! WARNING!! BE CAREFUL
JK FIRMWARE UPDATE PROCESS DOCUMENT link

Some videos from Andy from OffGrid Garage that may be helpful for anyone looking to update firmware or settings on the JK Inveter BMS

Update the Firmware Video

Generate New Password Video