The battery

A wheel has a battery management board watching over its cells. When the wheel is willing to report what goes on in there, the app puts it on a screen of its own.

What you see#

• The voltage of every cell.
• The lowest and highest cell, the average, and the spread between them.
• Battery, board and power switch temperatures.
• Charge current and discharge current.
• Full and remaining capacity, and the charge level.
• The number of charge cycles.
• The state of the charge and discharge switches, whether it is charging, whether a fault is flagged, and whether balancing is running.

On wheels with two batteries each one is shown separately, including left and right currents.

Why the spread matters#

The spread is the difference between the fullest and emptiest cell. On a healthy pack it is small, hundredths of a volt, and grows towards the end of a discharge.

If it has grown noticeably and stays there, stop running the pack to empty and have the wheel looked at. The app can warn you about this on its own: cell spread is one of the readings available in the alerts.

Why the data is sometimes missing#

Some wheels only report cell voltages on request, a page at a time, so the screen fills in gradually. Until every page has arrived the app says plainly how many cells it has so far.

Some wheels never report individual cells. Then only the overall level is shown, with a note that the battery board did not send the details.

When the series-cell count is known, the app can still show an average cell voltage by dividing the pack voltage by that count. Choose the correct model in the dashboard menu if the app cannot recognise it; see wheel model selection. Individual cells cannot be recovered that way, so such a wheel has no minimum and no maximum, but the familiar "volts per cell" is there. That is the figure that carries from one wheel to the next: a hundred-odd volts across the pack tells you nothing, 3.7 per cell tells you everything.

Battery model and remaining range#

The BMS screen shows measurements reported by the wheel. Predicted charge and Predicted range are separate estimates that learn from your rides. Under Settings → Data → Battery model you can inspect the learned model and train it on past rides. Training shows which rides qualify and why others were excluded. See predicted charge and range for how the estimates work.

A manual model pick with a different series-cell count clears the old fitted battery model: a fit for a different pack cannot be reused. Select the actual wheel model before training.