Anyone else had issues with Victron MPPT dropping connection overnight?

Had this exact problem on the narrowboat last winter — SmartSolar 100/30 kept dropping out of Bluetooth overnight, usually when temps dropped below about 4°C. Drove me absolutely mad trying to diagnose it.

Turned out to be a combination of two things for me:

1. Firmware — I was a couple of versions behind. Updated via VictronConnect and it made a noticeable difference straight away
2. Phone Bluetooth — my Android was aggressively killing background apps overnight, so sometimes it wasn't the MPPT dropping at all, just my phone losing the connection and not re-establishing it

The actual controller losing comms is a different beast though. If you're seeing it in VRM rather than just the app, that points more toward a dodgy VE.Direct cable or the Venus OS device (if you've got a Cerbo or similar) having a wobble.

Worth checking:

• Is it logging gaps in VRM or just the app?
• Any condensation near the unit? Had a mate with a cabin setup where moisture ingress was killing the connection intermittently
• What firmware version are you on?

My backup setup at home runs a 75/15 and that's been rock solid by comparison — smaller unit, simpler install, never missed a beat. Makes me think the 100/30 just has more going on to go wrong.

Would be curious whether others are seeing this seasonally or year-round — I genuinely wonder if it's more of a cold-weather thing with the Bluetooth module specifically.

What's your setup — direct Bluetooth or going through a GX device?

Reply by LauraGraham72

@BordersOffGrid Oh, this rings so many bells! We had almost identical behaviour with our 75/15 at the static caravan last winter. Turned out the issue was the Victron Connect app on my phone losing the "stay connected" preference after an update — worth checking your app version first as it's an easy fix if that's the culprit.

Also worth investigating whether your phone's battery optimisation settings are killing the Bluetooth connection overnight. Android is particularly aggressive about this. Go into your battery settings and whitelist the VictronConnect app specifically.

That said, if it's genuinely the controller dropping rather than your phone, check your firmware version. Victron pushed a patch around v3.14 that addressed some Bluetooth stability issues in cold conditions. The Victron community forum has a decent thread on it too.

Reply by DriftGal

@BordersOffGrid This actually took me down quite a rabbit hole when I first moved into my tiny house full-time. The Bluetooth dropout isn't the controller failing — it's the CC2564 Bluetooth module entering a deep sleep state that's technically working as designed, but the wake threshold gets miscalibrated in cold temps.

What sorted it for me: make sure your firmware is absolutely current via VictronConnect, because they quietly patched the sleep behaviour on the SmartSolar range a while back without much fanfare. Also worth checking whether your phone's Bluetooth is actually the culprit — iOS in particular aggressively kills background BLE connections.

The connection itself being severed overnight doesn't mean your charge data is corrupted, mind you. Your daily yield history should still be intact when you reconnect in the morning.

Reply by LH_Marine

@BordersOffGrid Almost certainly a firmware issue combined with the nRF52 Bluetooth module struggling at low temps — seen it repeatedly on both my narrowboat and the shepherd's hut setup.

Two things worth trying before anything else:

1. Update firmware via VictronConnect — several releases between v1.59 and v1.61 specifically addressed BT stability
2. Check your phone's Bluetooth power-saving settings — Android in particular will aggressively kill background connections overnight

If it persists post-update, the Victron GX portal (even a cheap Cerbo GX) bypasses Bluetooth entirely and gives you wired VE.Direct comms — rock solid at any temperature.

Worth also checking the unit isn't mounted somewhere with significant thermal cycling. Mine was near the engine bay initially; moving it sorted half the problem.

Don't bother with the PIN reset workaround floating around — that's treating the symptom, not the cause.

Reply by DerekMoore89

@LH_Marine interesting point about the nRF52 — hadn't considered the module itself being the culprit. I've noticed something similar on my motorhome setup with a 100/20, though mine tends to drop around 2-3°C rather than 4°C.

Quick question for the thread: does yours reconnect automatically come morning once temps rise, or do you have to manually cycle the Bluetooth? Mine usually comes back on its own but occasionally I have to toggle it in VictronConnect.

Also wondering whether this is specific to the SmartSolar range or whether anyone's seen it on the BlueSolar units too — I'm planning a second install on a shepherd's hut project and trying to decide whether to go SmartSolar or save a bit and go BlueSolar given it's a static setup where I won't need Bluetooth constantly anyway.