⚠️ Updated for v1.6.3 — the toggle-soup is gone.v1.6.3 (#277) replaces the four-switch architecture this guide describes (
ev_charging_mode×night_charging×smart_night_charging×tariff_optimized) with one named per-chargerCharge modeselector. The five modes are:
Mode What it does When to pick Solar only Pure surplus, never grid Solar maximalist Solar + cheapest hours Surplus by day, grid only in the cheapest tariff windows (hidden if no dynamic tariff configured) Dynamic-tariff users Min + Solar (default) Guarantee Min from grid/night top-up, solar adds up to Max. Zone-adaptive during the day — Min comes from night charging, not forced grid pull at noon. Daily commuter needing a baseline Always (max) Charge at maximum regardless of source "Just charge the car" / strict legacy- minpvbehaviourOff No charging Disabled Plus the existing Charge Target range (Min / Max), Charge by HH:MM deadline, and Set as default button as the per-mode detail. The old standalone switches (
night_charging,smart_night_charging,tariff_optimized,ev_charging_mode) are removed — automations that read them must read the newselect.sem_charger_<id>_charge_modeinstead.The behavioural-priority cascade below (Min ▷ Charge by ▷ Cheapest hours ▷ Smart night ▷ Mode ▷ Surplus) still applies — the intent moved into the mode selector. A full rewrite of this guide tracking the new model is tracked separately; the historical detail below remains accurate for the pre-v1.6.3 toggle layout but the entity names have changed.
The sections below describe the toggle architecture that v1.6.3 consolidated. Kept for now so existing dashboards and automations migrating off the old switches have a reference; will be rewritten in a follow-up release to describe only the new mode selector.
SEM's EV controller takes input from up to 6 user controls plus solar, battery, grid, and (optionally) tariff prices. This guide is the canonical reference for how those inputs interact.
TL;DR — the priority cascade: Min ▷ Charge by ▷ Cheapest hours ▷ Smart night ▷ Charging Mode ▷ Surplus opportunism
Min always wins. Tariff and smart-skip only fire when they don't risk Min. "Up to Full" is opportunistic — never forces grid.
SEM splits EV charging into two time domains and three layers:
Daytime (solar hours) Night window (e.g. 20:30 – 07:00)
────────────────────── ─────────────────────────────────
Layer A — Mode Charging Mode (select) (night logic always applies)
Layer B — Toggles Cheapest hours Overnight grid charging
Smart night charging
Cheapest hours
Layer C — Floors At least X kWh At least X kWh
Up to Full Charge by HH:MM
Min / Max current Min / Max current
Layer A and Layer B are independent: turn them on or off in any combination. Layer C is always in force.
| Mode | Grid use | Solar use | When to pick |
|---|---|---|---|
| Auto (default) | Forecast-aware. Sunny tomorrow → no grid today; cloudy → falls back to Min+PV | Surplus first | Set & forget |
| PV | None (battery may assist if above floor SoC) | Surplus + battery-assist | Solar maximalist |
| Self-consumption | None ever | Pure surplus, battery untouched | Battery-cycle-averse |
| Min+PV | Up to Min current always, plus surplus on top | Min floor + solar bonus | Daily commuter needing a baseline |
| Now | Max immediately | Whatever's there | "Just charge the car" |
| Off | None | None | Disabled |
Now and Off ignore all night and tariff logic — explicit user override wins.
| Card label | Internal entity | Default | Effect |
|---|---|---|---|
| Overnight grid charging | switch.sem_charger_<id>_night_charging |
ON | Master switch for the night window. OFF = no grid charging overnight regardless of other settings. |
| Smart night charging | switch.sem_charger_<id>_smart_night_charging |
OFF | Skips tonight if Solcast forecast covers Min tomorrow. SoC-aware so a low car never gets skipped. |
| Cheapest hours (tariff) | switch.sem_charger_<id>_tariff_optimized |
OFF | Defer night charging to the cheapest contiguous price window. Min still guaranteed. |
| Charge by HH:MM | time.sem_charger_<id>_target_time |
window end | Deadline for hitting Min. Earlier than window end = forcing floor that overrides peak limit. |
| Set as default | button.sem_charger_<id>_set_default_target |
— | Copy this charger's Min/Max/deadline to global defaults for new chargers. |
| Card label | Role |
|---|---|
| At least X kWh | Hard floor — guaranteed by Charge by time. Cannot be overridden by tariff or smart-skip. |
| Up to Full | Opportunistic ceiling — surplus and cheap-hour bonus only; never forces grid. |
| Min current (e.g. 6 A) | Lowest current the charger runs at (most cars won't accept charge below this). |
| Max current / Initial night A | Upper bound. Also the rate a forcing deadline can ramp to. |
| Phases (1 or 3) | Determines watts-per-amp (~230 W/A 1-φ, ~690 W/A 3-φ). |
The home battery can feed the EV when solar isn't enough.
| Setting | Effect |
|---|---|
| Battery assist floor SoC (e.g. 60 %) | Battery only assists EV above this SoC |
| Battery assist max power | Discharge cap when assisting |
Active in Auto and PV modes. Not in Self-consumption (by design) or Now (which takes everything).
The opt-in tariff_optimized switch changes behaviour in three places — not just at night:
| Time | Charging Mode | What tariff_optimized does |
|---|---|---|
| Night | any | Waits for cheapest contiguous window before charging (subject to Min reachability) |
| Daytime | Min+PV | Drops the Min+PV grid guarantee on EXPENSIVE / VERY_EXPENSIVE hours. Falls back to surplus-only; resumes on price drop or sufficient solar |
| Daytime | PV / Self-consumption / Auto | No effect (these modes don't use grid anyway) |
| Anytime | Now / Off | No effect (explicit override) |
Cheap price threshold (e.g. 0.15) and Expensive price threshold (e.g. 0.35) define the boundaries when no dynamic provider gives level labels.
The complete decision space, in one table. Use this as the lookup when reasoning about a specific situation.
| # | Time | Charging Mode | Overnight | Cheapest | Other | What SEM does | Status sensor |
|---|---|---|---|---|---|---|---|
| 1 | Day | Auto | — | — | Surplus available | Charge from surplus; current ramps with PV | solar_only |
| 2 | Day | Auto | — | — | Sunny tomorrow forecast | Skip today — wait for tomorrow | idle |
| 3 | Day | Auto | — | — | Cloudy forecast, surplus low | Fall through to Min+PV (grid Min + PV bonus) | min_pv |
| 4 | Day | PV | — | — | Battery SoC > floor, solar < EV need | Battery assists, tops up to EV minimum | battery_assist |
| 5 | Day | PV | — | — | Battery SoC < floor | Idle (no grid, battery off-limits) | idle |
| 6 | Day | Self-consumption | — | — | Surplus available | Surplus only; battery untouched | solar_only |
| 7 | Day | Min+PV | — | OFF | any price | Min current + PV bonus, always | min_pv |
| 8 | Day | Min+PV | — | ON | Price = normal/cheap | Min current + PV bonus | min_pv |
| 9 | Day | Min+PV | — | ON | Price = expensive | Pause grid; surplus-only until price drops | solar_only |
| 10 | Day | Now | — | — | any | Max current immediately (overrides everything) | now |
| 11 | Day | Off | — | — | any | Idle | idle |
| 12 | Night | any | OFF | any | any | Idle — overnight grid charging disabled | night_disabled |
| 13 | Night | any | ON | OFF | Smart night ON, sunny forecast, SoC OK | Skip tonight + notification "forecast covers Min" | night_skipped |
| 14 | Night | any | ON | OFF | Deadline = window end | Gentle ramp, peak-managed (legacy 1.5.x behaviour) | night_charging |
| 15 | Night | any | ON | OFF | Deadline earlier than window end | Forcing: scales current up to hit Min; can overshoot peak | night_charging (deadline_active) |
| 16 | Night | any | ON | ON | Cheap window covers Min at peak-rate | Waiting for cheap hours until window opens |
tariff_waiting_for_cheap |
| 17 | Night | any | ON | ON | Cheap window too short at peak-rate | Override tariff; charge now ("not enough cheap hours") | night_charging |
| 18 | Night | any | ON | ON | No price data (provider down) | Override tariff; charge now | night_charging |
| 19 | Night | any | ON | any | Deadline physically impossible | Charge at max + push notification "can't reach Min in time" | night_charging (reachable=false) |
| 20 | Night | any | ON | any | Min already met | Idle — only top up to Up to Full from surplus if it arrives | night_target |
Every 10 s during the night window, for each charger:
1. Min already reached? → idle (only top up to "Up to Full" from surplus).
2. Compute deadline_amps = ceil( remaining_kWh / hours_left / watts_per_amp )
clamped to [Min current, Max current].
3. Compute effective_rate = Max current if forcing deadline (deadline earlier than window end)
peak_managed_amps otherwise ← peak-aware (#274/C1)
where peak_managed_amps = (peak_limit − avg_overnight_home_W) / watts_per_amp.
4. Reachable? = (remaining_kWh / effective_rate) ≤ hours_left.
5. If Cheapest hours ON:
a. Now is cheap? → charge.
b. Not reachable anyway? → charge (don't add tariff penalty on top of an already-failing deadline).
c. Sum cheap hours BEFORE deadline × effective_rate ≥ remaining_kWh?
yes → WAIT (state = tariff_waiting_for_cheap)
no → charge now ("not enough cheap hours at peak-limited rate")
6. Apply current = max(deadline_amps, gentle_ramp_amps).
If shared peak budget exceeded (multi-charger), throttle proportionally (#274/H1).
- 8.5 kWh Min, deadline 07:00 (= window end), tariff OFF, smart-night OFF
- Plug in at 22:00, SoC at 30 %, remaining_to_min = 8.5 kWh
- Solar tomorrow's forecast irrelevant (smart-night off)
- Hours to deadline = 9
- Required rate = 8.5 / 9 = 0.94 kW = ~1.4 A at 3-φ
- Below the 6 A minimum → ramps to 6 A and finishes ~02:00, idles to 07:00.
- Same setup but Cheapest hours ON
- Cheap window 01:00–05:00 (4 h)
- effective_rate = peak_managed_amps × 690 W/A ≈ 4.1 kW (assuming 6 A peak headroom)
- Deliverable in cheap window = 4 × 4.1 = 16.4 kWh > 8.5 kWh ✓
- SEM idles from 22:00, status =
tariff_waiting_for_cheap, "Next: 01:00" shown on card - At 01:00 it charges; finishes ~03:00; idles to 07:00.
- 30 kWh Min (almost full charge), deadline 07:00, Cheapest hours ON
- Cheap window 01:00–04:00 (only 3 h)
- effective_rate = 4.1 kW
- Deliverable = 3 × 4.1 = 12.3 kWh < 30 kWh ✗
- SEM does not wait. Charges immediately from 22:00 onward; status =
night_charging. - Card reason: "tariff: not enough cheap hours at the peak-limited rate — charging now to guarantee Min"
- 8.5 kWh Min, deadline = 03:00 (earlier than window end), tariff OFF
- Hours to deadline = 5
- Required rate = 8.5 / 5 = 1.7 kW ≈ 2.5 A → clamped to 6 A floor anyway
- BUT: deadline is "forcing" so SEM bypasses the peak-managed rate. If peak limit would normally throttle to 4.1 kW, the deadline-floor pushes through.
- Status:
night_charging,deadline_active = true. If this would breach the peak limit, the user has explicitly accepted that trade-off by setting an early deadline.
- Min+PV mode, Cheapest hours ON, midday cloudy day
- Min current would normally pull from grid to maintain 6 A floor
- Price hits
EXPENSIVElevel at 12:00 - SEM drops to surplus-only: if solar < 6 A worth, the charger pauses. Resumes when price drops back to normal or solar covers it.
Each charger has its own daily energy bucket (daily_ev for that charger). The bucket rolls over at the charger's own Charge by time (defaults to the night window end, e.g. 07:00).
Why not at sunrise? Sunrise can be earlier than the night-window end on short summer nights (sunrise 05:30, window end 07:00). A sunrise-based reset would wipe the bucket after Min was met (~03:00) but before the night window closes — making SEM see remaining = daily_target again and re-fire night charging until 07:00, double-billing the user. The deadline-based boundary closes that window: the bucket only rolls over once today's commitment is done. (#280)
Multi-charger: each charger's bucket resets at its own deadline. Car A at 07:00 and Car B at 08:00 reset independently — Car B isn't disturbed when Car A's day rolls over.
Solar between sunrise and the deadline: still counted into yesterday's bucket. Harmless, since Min was already hit.
- 1.5.x and earlier: only
night_charging+smart_night_chargingexisted. No deadline, no tariff-aware night. Daily bucket reset at sunrise (had the double-charge race condition above). - 1.5.16 (unreleased):
Charge bytime picker (#246) — per-charger deadline with forcing behaviour.Cheapest hours (tariff)opt-in switch (#247) — night defer + daytime Min+PV pause.- Reachability uses peak_managed_amps, not nameplate max (#274/C1) — prevents tariff-wait → miss-Min.
- Multi-charger night runs on a shared peak budget (#274/H1).
- DST-correct hour subtraction (#274/M2).
- "Set as default" button (#246) — propagate per-charger settings to global defaults.
- Daily bucket reset moved from sunrise to per-charger deadline (#280) — kills the summer double-charge race.
| Symptom | Likely cause | Where to look |
|---|---|---|
| EV idle overnight despite plugged in | Overnight grid charging OFF, or Min already reached | EV card → Overnight grid charging toggle; check sensor.sem_charger_*_session_energy |
| Tariff "waiting" all night, never charges | Cheap window past midnight didn't open, OR price provider went stale | EV card → Cheapest hours hint shows "Next: HH:MM"; check sensor.sem_tariff_current_import_rate attributes |
| Charging at high current even when no solar | Forcing deadline set earlier than window end | EV card → Charge by time. Set it to window end (e.g. 07:00) to disable forcing. |
| "Can't reach target in time" notification | Min too high for the time left at max current | Lower Min, set an earlier deadline, raise Max current, or accept the notification (charges to whatever is possible at max) |
| Multi-charger: one stays idle | Shared peak budget allocated to higher-priority charger first | Surplus priority + daily_ev_target per charger; check coordinator logs for peak-budget allocation |
| Daytime Min+PV not pulling grid on cloudy day | Cheapest hours ON + price = EXPENSIVE | Either accept the pause or turn Cheapest hours OFF |
| Daily target counter shows yesterday's number into the morning | Working as intended — bucket only resets at Charge by time | sensor.sem_charger_*_daily_ev. Pre-#280 reset at sunrise; now at deadline to prevent double-charge race |
- README — Recent Improvements — release notes for each version
- USER_GUIDE — Configuration Options — full settings reference
- MULTI_DEVICE_GUIDE — multi-charger setup
- DASHBOARD_GUIDE — card-by-card UI reference
- TROUBLESHOOTING — general issues