JK Preset Studio

JK-BMS live monitor over Bluetooth

Connect your JK BMS over Bluetooth and watch it work: pack and cell voltages, current, power, state of charge and temperatures, live in the browser. Readings are kept on this device only.

What you see

Live values

Voltage, current, power, state of charge with a time-to-full or time-to-empty estimate, temperatures and MOSFET state, about once a second.

Every cell

Each cell with its deviation from the average, the highest and lowest marked. Click a cell to plot it over time.

History chart

Cells, pack voltage, current, power, SOC and temperatures on one time axis, with the protection limits of your BMS drawn in.

Alarms and warnings

Alarms reported by the BMS, plus warnings when a cell or temperature gets close to a protection limit.

Event timeline

When charging or discharging switched, the balancer ran, alarms came and went, and the connection dropped.

Saved recordings

Each session is stored in the browser for a week, so you can open it again later without the BMS.

Questions

Which browsers work?

Chrome or Edge on Windows, macOS, ChromeOS and Android, which support Web Bluetooth. Firefox, Safari and iOS browsers cannot connect, but the demo runs everywhere.

Can I use the JK app at the same time?

No. The BMS accepts one Bluetooth connection at a time, so close the JK app before you connect here.

Does the monitor change any settings?

No. It only listens to the values the BMS sends. Settings change only when you press Write to BMS in the editor.

What happens when the connection drops?

The monitor tries to reconnect on its own several times, and the chart shows a gap for the time without data. If that fails, press Reconnect.

Where is the history stored?

In this browser only (IndexedDB), for seven days. Nothing is uploaded, and you can delete a recording at any time.