fix: EVC register segmentation, firmware-version gating, doc-aligned entities

SolaX support (ticket 703158) confirmed the EVC holding registers are
internally segmented: 0x600-0x650 is one segment, 0x660-0x66F another
(used for master-slave parallel operation). A function 0x03 read that
spans the boundary silently returns 0 for second-segment registers.
Reproduced on an X3-EVC-11kW Gen1 (ARM V1.18). Fixed by starting a new
read block at 0x668 and restoring the default block_size 100 (the
block_size=32 workaround predating this knowledge is no longer needed).

The plugin now publishes its firmware version (input 0x25, e.g.
V1.18 -> 118) as hub.modbus_protocol_version, enabling modbus_min/
modbus_max gating for EV chargers. Entities on registers dated by the
protocol document's revision history are gated accordingly, and every
register pair that changed location across firmware versions is exposed
as a single entity identity whose backing register follows the
firmware: Charge Power 0x08-0x0A -> 0x100-0x102, Run Mode 0x1D ->
0x106, Charge Phase 0x625 -> 0x63B, Charge Mode (0x104 sensor on
V1.12-13, 0x641 select from V1.14, 0x669 select on GEN2). The
Alt-suffixed duplicate entities are gone.

Support suggested using the documented 0x64F (limit_current_allmode)
for the maximum current. Live testing shows it is the persistent
device limit rather than the setpoint (SolaXCloud itself writes 0x668;
external writes to 0x64F are acknowledged but ignored), so Max Charge
Current stays on 0x668 and a new optional max_key field on number
descriptions caps the Max/Min Charge Current sliders dynamically from
the 0x64F readback.

New doc-based entities (disabled by default unless noted): Unbalanced
Power 0x63C and Unbalanced Switch 0x63D (X3), Mode Button 0x63E, Min
Charge Current 0x63F, Datahub Charge Power 0x643, Green 30s Delay
0x644 (switch), Parallel Support 0x107, WiFi S/N 0x607, Customized S/N
0x629. Alignments: Overload Limit renamed Overvoltage Limit (doc
OverVoltSet), Charger Type name unified across GEN1/GEN2, RSSI renamed
WiFi RSSI, per-phase Charge Current sensors consistently disabled by
default, Datahub Charge Current disabled by default, charge_added_cum
GEN2 scope narrowed from GEN2|GEN3|GEN4. Input 0x2D/0x2E are marked in
code as conflicting between the Gen1 V3.5 and GEN2 documents
(clarification requested from SolaX). Register 0x642 Parallel_enable
is deliberately not exposed: the device returns values outside the
documented 0/1 range and SolaXCloud's parallel toggle does not use it.

Author: Bl00d-B0b

custom_components/solax_modbus/const.py

@@ -390,6 +390,7 @@ class BaseModbusNumberEntityDescription(NumberEntityDescription):
     prevent_update: bool = False  # if set to True, value will not be re-read/updated with each polling cycle;
     # update only when read value changes
     sensor_key: str | None = None  # only specify this if corresponding sensor has a different key name
+    max_key: str | None = None  # key of a sensor whose value dynamically overrides native_max_value
     depends_on: list[str] | None = None  # list of modbus register keys that must be read
     display_as_box: bool = True  # display numbers as an input box (default); set False for a slider.
     suggested_display_precision: int | None = None

custom_components/solax_modbus/number.py

@@ -184,6 +184,15 @@ def name(self) -> str:
     def unique_id(self) -> str | None:
         return f"{self._platform_name}_{self._key}"
 
+    @property
+    def native_max_value(self) -> float:
+        max_key = self.entity_description.max_key
+        if max_key:
+            value = self._hub.data.get(max_key)
+            if value:
+                return float(value)
+        return self._attr_native_max_value
+
     @property
     def native_value(self) -> float | None:
         descr = self.entity_description
@@ -267,6 +276,10 @@ async def async_set_native_value(self, value: float) -> None:
                 f"writing {self._platform_name} {self._key} number register {self._register} value {pl} after div by readscale {self.entity_description.read_scale} scale {self._attr_scale} with mode {self._write_method}"
             )
             await self._hub.async_write_registers_multi(unit=self._modbus_addr, address=self._register, payload=pl)
+        if self._write_method in (WRITE_MULTISINGLE_MODBUS, WRITE_SINGLE_MODBUS, WRITE_MULTI_MODBUS):
+            # Publish the written value locally: the readback register only catches up on a
+            # later poll, so the entity would otherwise keep reporting the previous value.
+            self._hub.data[self._key] = value
         elif self._write_method == WRITE_DATA_LOCAL:
             _LOGGER.info(f"*** local data written {self._key}: {payload}")
             # corresponding_sensor = self._hub.preventSensors.get(self.entity_description.key, None)