Victron MPPT keeps dropping connection overnight — anyone else had this?

Had this exact saga last winter with my SmartSolar 100/30. Drove me absolutely mad — wake up to check VictronConnect and it'd lost the Bluetooth link sometime around 3am every single night like clockwork.

Turned out to be two separate culprits working against me:

1. Phone Bluetooth — iOS was aggressively dropping the connection in low-power mode overnight. Switching to a dedicated old Android tablet fixed the monitoring side of things.
2. Firmware — the controller itself was on an older firmware version. After updating through VictronConnect the phantom disconnects almost completely stopped.

Worth checking your VE.Direct cable too if you're running one to a Cerbo or similar. Mine had a slightly dodgy seating on the controller end — not loose enough to notice by eye, but enough to cause grief when temperatures dropped overnight and everything contracted slightly.

One thing I'd ask — are you seeing actual data gaps in your history graphs, or just the app losing its live connection? They're different problems. If it's gaps in the logged data, the controller itself is resetting, which is a whole different rabbit hole involving power supply stability to the unit.

My setup is off-grid full-time, so reliable overnight logging matters enormously to me — I need to know what my Fogstar batteries are doing through the night rather than finding surprises in the morning.

What firmware version are you currently on? And are you connecting direct Bluetooth or through a GX device? That'll narrow it down considerably.

Anyone else had the cold-contraction issue with VE.Direct connections specifically? Curious whether that was just my dodgy luck or a known thing.

@SprinterLife had almost identical with my 75/15 in the shepherds hut last year. Turned out the issue was the Victron going into a very deep sleep state when solar input drops to zero and battery load is minimal — BT essentially powers down.

Two things that sorted it for me:

• Enabling "Keep BT on" in the VictronConnect settings (not available on all firmware versions mind you)
• Updating to the latest firmware via VE.Direct before assuming it's a hardware fault

Worth checking your battery load overnight too — if it's near zero the unit sleeps harder than you'd expect. Once I had a small parasitic draw keeping things ticking over, the dropouts stopped completely.

Still an annoying quirk of the SmartSolar range tbh. Victron's documentation on this is pretty vague.

Classic Victron "phantom disconnect" — the Bluetooth radio on the SmartSolar goes into a low-power sleep state when there's zero PV input overnight, and if your phone's BLE stack decides it's had enough at the same moment, the handshake never recovers until morning.

Worth checking:

• Keep-alive setting in VictronConnect → device settings (easy to miss)
• Disable battery optimisation for VictronConnect on your phone — Android is particularly savage about killing background BLE connections
• If you're running a Cerbo GX, let that maintain the persistent connection instead; phone Bluetooth becomes irrelevant

My own 150/35 did this until I stopped relying on direct phone BT altogether and just used the Cerbo — slept much better, metaphorically and literally given I wasn't checking my phone at 3am like a maniac.

Seen this on my 100/20 too. Worth checking whether it's actually dropping Bluetooth or whether VictronConnect is just timing out on the phone side — they're not the same thing.

What sorted it for me was keeping the app "active" by enabling live data logging to VRM. Not ideal if you're off-grid on limited data but it seemed to keep the radio from going fully dormant.

Also — and this sounds daft — check your phone's battery optimisation settings. Android in particular will absolutely murder background Bluetooth connections overnight. Samsung being the worst offender in my experience. Whitelisting VictronConnect made a noticeable difference before I even touched the MPPT settings.

@OldSailor is probably right about the sleep state but sometimes it's the phone killing the connection rather than the unit itself.

Had this exact same thing in my shepherd's hut build last summer. Turned out to be my phone's aggressive battery optimisation killing the VictronConnect app in the background — not actually a controller issue at all.

Worth checking Settings > Apps > VictronConnect and disabling battery optimisation entirely. On Android especially it'll throttle background connections hard after midnight when the screen's been off a while.

Also noticed my 100/30 was fine once I kept a cheap dedicated tablet plugged in permanently just for monitoring. Bit of a workaround but rock solid since.

@LiFePO4Fan makes a fair point about distinguishing a real drop vs a timeout — if your controller history shows no gap in the charge data overnight, it's almost certainly the app/phone side rather than the unit itself.

@MikeCross same thing happened to me in my hut build actually. Android or iPhone?

On Android I had to go into battery settings and specifically exclude VictronConnect from optimisation — not just "allow background activity" but the full unrestricted mode. Took me ages to find it buried in the manufacturer settings rather than stock Android.

Also worth checking: if you're running a Fogstar or similar LiFePO4 that drops to a very low resting draw overnight, the MPPT itself can enter a weird low-consumption state. Not sleep exactly, just... odd. Rebooting the unit via the side button sorted mine temporarily but the phone settings fix was the permanent solution.

What firmware version are you on? Victron pushed an update a while back that apparently improved BT stability.