Had this exact issue on my narrowboat last winter with a SmartSolar 100/30. Drove me absolutely mental for weeks.
Turned out to be two separate things ganging up at once:
-
Bluetooth timeout — the VictronConnect app was dropping the display connection, not the controller itself. Easy to confuse the two if you're monitoring remotely. Check whether your actual charge data is still logging correctly in the history tab.
-
Actual controller restart — this was the sneaky one. My battery voltage was dipping low enough overnight that the MPPT was briefly resetting. Once I sorted my battery bank (moved to a 200Ah Fogstar Drift LiFePO4), it stopped entirely.
Worth checking a few things:
- What does the history tab show? Any zero-output gaps that shouldn't be there?
- Are you on the latest firmware? There was a dodgy firmware version a while back that caused instability with certain battery profiles
- Is the unit getting cold? I had condensation issues in the engine bay that caused intermittent grief
If you're on a boat or cabin with significant temperature swings overnight, that's worth factoring in. Victron gear is generally solid but it's not magic — the installation environment matters a lot.
What controller model are you running and how's it wired? That'll help narrow it down. Others here will have more specific experience depending on your setup.