Per charge-mode phase preset (lock Slim to 1P, Now to 3P)

[Dextro86]

Feature description
Option to lock phases per charge mode. Example: Smart (PV / Min+PV) always 1-phase following solar surplus, Now always 3-phase max. No automatic 1P↔3P switching inside Smart mode.

Motivation
On some chargers automatic phase switching is unstable. Avoiding 1P↔3P in Smart mode makes solar charging much more stable. Now stays available for instant full-power 3P charging.

Proposed solution
Two new optional loadpoint settings, e.g. phasesSmart: 1 and phasesNow: 3 (or: remember last manual phases choice per mode). When mode changes, evcc applies the preset. Default behaviour unchanged when not configured.

Alternatives considered

Manual switching via POST /loadpoints/{id}/phases/{phases} or Home Assistant automation — works, but not automatic on mode change.
Global phases: 1 — blocks fast 3P charging completely, so not acceptable.
Related: #31313 (immediate fallback to 1P on Now→PV), but this request is about the option of never switching inside Smart at all.

[Tuttivini]

I strongly support this feature request. I experience similar instability with automatic phase switching during solar charging. Having preset phase limits per charge mode (e.g. fixed 1P for Smart/PV and 3P for Now) would make solar charging much more reliable for my setup as well.

[Dextro86]

Update: implemented as PR #34538 (ready for review). It adds optional phasesSmart / phasesNow presets — applied on mode switch, actual switching stays in the control loop. Default behaviour unchanged. Feedback welcome!

[VolkerK62]

I would welcome that option. Currently, I manually switch to 1p in smart mode.

Because of my small PV system, I only briefly have more than 4.6 kW (20 A @ 1p) of excess power at midday. Switching to 3p would just be a nuisance then.

[Tuttivini]

Same situation here! With 19 400wp panels on Enphase Iq7+ microinverters (~5.6 kWp max output), my solar excess rarely stays above the ~4.1 kW threshold required for 3-phase charging (3x6A). Keeping Smart/PV mode locked to 1P allows me to seamlessly cover the entire 1.4 kW to 4.6 kW range (up to 20A on 1P) without constant phase switching. Meanwhile, having 'FAST' automatically switch to 3P is perfect when I need a fast charge or want to max out during negative dynamic electricity prices.
Really hoping this gets merged soon! Really hoping this gets merged soon!

[VolkerK62]

@Dextro86 what about "minSoc", "plan" and "price" charging? This happens in "smart" mode.

[mfuchs1984]

Yes, those cases should be equivalent to fast charging.

[Dextro86]

@Dextro86 what about "minSoc", "plan" and "price" charging? This happens in "smart" mode.

Good point, and mfuchs1984 is right: those cases run fastCharging() inside smart mode, so locking them to the smart (1p) preset would slow them down. Just pushed an update to #34538: each control tick now picks the governing preset — fast-equivalent charging (planner active, minSoc not reached, cheap smart cost) uses the now preset, pure surplus following keeps the smart preset. Actual switching still goes through the normal phase timers and load management. Default behaviour unchanged when no presets are set.