JK BMS Monitor

Jiří Wendl

About this app

JK BMS Monitor connects to your JK (Jikong) battery management system over
Bluetooth LE and shows what your battery is doing — reliably.

It was built as a replacement for the vendor app, with a focus on the things
that matter when you actually depend on the data:

• Automatic reconnection. A dropped link is re-established on its own, and a
watchdog forces a reconnect if the BMS goes quiet. The last readings stay on
screen while it does, instead of the app going blank.
• Status: state of charge, pack voltage, current and power, charge/discharge
MOSFET state, balancer state and current, heating, temperatures (MOS and
sensors), state of health, cycle count, runtime — and a prominent alarm card
whenever the BMS reports a problem.
• Cells: every cell voltage on a stable scale (at least 100 mV around the pack
midpoint, so noise on a balanced pack doesn't make the bars jump), min / max
/ average, cell delta, wire resistances.
• Settings: read and change the BMS protection limits, balancer parameters,
capacity and the charge / discharge / balancer switches. Editing is locked
behind a risk notice; every change is confirmed and re-read from the BMS.
• Log: the event log the BMS keeps in its own memory, with the age of each
entry.
• Info: model, hardware and firmware version, serial number, manufacturing
date, uptime, power-on count.

Supported devices: JK BMS units with the Bluetooth (JK02) protocol, both the
24S layout of older hardware and the 32S layout of newer hardware and the PB
model family. The layout is detected automatically.

Privacy: the app has no network access. Nothing is collected, nothing leaves
your phone. It only remembers the last BMS you connected to.

Important: changing BMS settings can damage your battery or connected
equipment. Do so only if you understand the values; you use this feature at
your own risk.

Not affiliated with Jikong / JK BMS.

What’s new

First public release.
• Automatic reconnection with watchdog
• Status, Cells, Settings, Log and Info tabs
• JK02 24S and 32S layouts, auto-detected