Missing visibility into DESS schedule reasons

My Victron setup does mysterious things at 3am and I've genuinely started anthropomorphising it — "what are you thinking?" I mutter at the Cerbo like it owes me an explanation.

Seriously though, the lack of visibility into why the dynamic ESS scheduler makes the decisions it does is maddening. It'll decide to charge the Fogstar batteries from the grid at some odd hour when I'm sat on decent solar forecast, and I'm left squinting at VRM wondering if I've misconfigured something or if the algorithm is just having a moment.

A few things I'd love to see:

• A reason log — even a simple "charging now because: predicted low solar tomorrow" would be transformative
• Confidence scores on the solar forecast it's pulling (because UK weather forecasting is, let's be honest, optimistic fiction)
• Some indication of which tariff windows are actually influencing the decision

Anyone else running DESS on an Octopus Agile or Flux tariff finding this? I'm never quite sure if my schedule is working for me or if I've accidentally taught it bad habits and it's just loyally repeating them.

It feels like being handed a very capable co-pilot who communicates exclusively in silence and shrugs. Victron's hardware is superb but the transparency around the scheduling logic feels like it's still catching up.

Would love to know how others are making sense of it — or whether you've just made peace with the chaos and check VRM retrospectively like a financial audit of your own confusion.

@OffGridHamish I know that feeling. My Cerbo on the static caravan does the same — makes decisions that seem baffling until you dig into the logs.

A few things worth checking:

• VRM Portal → Advanced → has a reasonable history but won't always explain why DESS chose a particular window
• The scheduled charge reasons are partly opaque by design — it's optimising against your grid tariff, solar forecast and SOC targets simultaneously
• Enable "Has DC system" logging if you haven't, gives slightly better granularity

Honestly the biggest frustration is Victron don't expose the DESS decision logic in any readable form. You're essentially trusting the black box.

What tariff are you on? Agile or similar? The 3am behaviour usually makes more sense once you map it against half-hourly pricing. Sometimes it's genuinely logical, it just doesn't bother telling you.

@OffGridHamish The frustration is real. DESS (Dynamic ESS) is essentially running a cost-optimisation algorithm against your tariff schedule, forecast load, and solar prediction — but it logs outcomes not reasoning, which is the gap that drives you mad.

What helped me enormously was enabling the dbus-spy feed on the Cerbo and logging to VRM with 1-minute granularity. You can then cross-reference the 3am behaviour against your import price slots. Nine times out of ten there's a perfectly rational explanation — it's pre-charging ahead of a peak window, or the SOC target shifted because the solar forecast updated overnight.

The actual feature request is valid though: Victron should expose the DESS decision tree in the VRM portal, not just the resulting charge/discharge curve. Other platforms do this. Worth raising on the Victron Community forum directly — their dev team do actually read it.

My Cerbo GX once woke me up at 2:47am with a relay click and I'm still not over it — turned out it was "optimising" against an Agile tariff slot that had already passed, which is exactly the sort of thing that'd get a human sacked on the spot.

The real fix Victron need to implement is a reason code logged alongside every DESS decision — even just "charging: cheap rate window" or "holding: forecast generation" would stop us narrating our own equipment like it's a nature documentary.

Until then, VRM Portal → Advanced → DESS log is your best mate, though calling it "transparent" would be generous.

@OffGridHamish Had exactly this frustration on the narrowboat. DESS doesn't expose its reasoning natively, but there's a practical workaround worth trying.

Pull the MQTT data from the Cerbo and log it alongside your tariff schedule and SOC. Once you plot them together, the "mysterious" decisions usually make sense — it's weighing import cost, predicted solar, and battery degradation avoidance simultaneously.

A few questions that might help narrow it down:

• Are you on Agile or a time-of-use tariff?
• What's your ESS minimum SOC set to?
• Have you got scheduled charging enabled alongside DESS? That can cause conflicting instructions.

The 3am behaviour is often just it topping up before a peak period. Doesn't make it less annoying, but at least it's not random. What firmware version are you running on the Cerbo? Some earlier builds had genuinely erratic scheduling behaviour.