SAFETY-87: peak guard uses every battery that can still give

At N>=2 a battery at or under its own peak reserve is held: it gives
nothing for the peak (weight 0 while the site gives) and the guard's need
is placed on the live, non-refusing batteries above theirs. The guard is
floor-limited, and alarms, only when those cannot hold the limit at full
power for ALARM_HOLD_S. The peak alarms no longer read "Not ready" or hold
the Home page at 0 W, because control keeps running. N=1 is byte-identical.

DECISIONS/SAFETY-87-guard-uses-able-batteries.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019DBUfvndgHwaV339Fvd2gr

goodwe_controller/DOCS.md

@@ -3157,6 +3157,10 @@ and what to do:
 - **A battery cut-out level is not known.** Fill in “Battery cut-out level”
   for each inverter in the settings.
 
+With several inverters, a battery at its peak reserve does not give for the
+peak and the others do. This alarm then comes only when the others cannot
+keep the period under the limit alone. Control keeps running meanwhile.
+
 The peak reserve only applies to keeping the peak down. Normal home use can
 still draw the battery below it, down to the battery cut-out level, where the
 battery switches itself off.
@@ -3252,7 +3256,9 @@ state of charge is unread, or when an inverter's `bms_soc_floor` (label
 “Battery cut-out level”) is missing, because the reserve is graded against it.
 Charging from the grid stays blocked meanwhile. With several inverters the
 notification names the battery at its limit (SAFETY-32), each graded against
-its own cut-out level. ⚠️ **The reserve binds the peak guard only
+its own cut-out level. That battery is held (weight 0 while the site gives)
+and the guard's need goes to the others, up to their rating; the alarm fires
+only if they miss the limit at full power for `ALARM_HOLD_S` (SAFETY-87). ⚠️ **The reserve binds the peak guard only
 (SAFETY-25).** Self-consumption has no such floor. See *What `peak_soc_floor`
 does not protect*.
 
@@ -3390,7 +3396,7 @@ for a new install*.
 | Meter reading may be stuck | See *Meter reading may be stuck* under Notifications. |
 | Month peak | This month's highest 15-minute average, when it happened, and how close it is to your peak limit. Amber from 80 %. |
 | 15-minute periods measured this month | How many 15-minute periods the add-on has measured and saved this month. |
-| Peak guard, Load too high for battery, Battery at its peak reserve | What the add-on does to keep your peak down. *Idle, heading for …* is where this 15-minute period is heading. *Waiting for meter readings* after a restart means the battery does not charge until the add-on can measure the period again. |
+| Peak guard, Load too high for battery, Battery at its peak reserve | What the add-on does to keep your peak down. *Idle, heading for …* is where this 15-minute period is heading. *Waiting for meter readings* after a restart means the battery does not charge until the add-on can measure the period again. A red peak row is an alarm while control keeps running, so the banner shows its title without *Not ready*. |
 | Battery level, Battery power, Grid power | The reading of that entity. *No usable reading* means the entity is missing, or its reading is too old. Check it in Developer Tools before replacing it. |
 | Inverter control | Whether the inverter can be controlled, and how much it can charge and give. |
 | *name*: battery power reading stopped changing | The reading did not change while the add-on asked for a change. It may be stuck, or the battery may be refusing. The add-on sets the inverters to 0 W until it changes. |