A device shows no readings ("--")

Dashes mean the device is installed but the panel has never received a valid value from it. That's different from a device that stopped updating (see A device stopped updating).

Just added it?

Adding a device needs a restart to take effect — check the Devices page for the amber Restart to apply badge.

Victron device? It's the key.

A wrong or missing bindkey shows no error — the card just stays at "--" forever. Re-copy the 32-character encryption key from the VictronConnect app and make sure "Instant readout via Bluetooth" is enabled. Full steps: Victron devices.

Wrong device type?

A device added as the wrong type may even connect but never produce readings. If it was added from Discovered nearby with a "best guess" marker, open it on the Devices page and confirm the type matches the actual product; re-add with the right type if not.

Known blanks

A few readings are legitimately empty: the Renogy card's alternator input figures aren't reported yet, a Victron shunt only reports starter-battery voltage if its aux input is configured for it, and OBD-II values need the ignition on.

A Monoty A6 tank input with no probe wired to it also stays at "--": the panel would rather show nothing than show an unconnected input as an empty tank. See Monoty A6.