fix: PV_in_current ora è la corrente reale lato pannelli

Precedentemente DATA[25] (corrente SCC→batteria a tensione batteria)
veniva pubblicato direttamente come PV_in_current, dando valori errati.

Calcolo corretto via conservazione energia nell'SCC (DC-DC converter):
  P_pv   = V_batt × I_scc        (potenza SCC output = potenza pannelli)
  I_pv   = P_pv / V_pv           (corrente reale pannelli a tensione PV)
  P_pv   = V_pv × I_pv           (invariato - solo presentazione diversa)

Esempio con: V_pv=240V, V_batt=55V, I_scc=5A
  Prima: PV_in_current = 5A   (corrente SCC a 55V, errata)
  Dopo:  PV_in_current = 1.15A (corrente reale pannelli a 240V, corretta)
  PV_in_watts = 275W in entrambi i casi (matematicamente invariato)

sources/inverter-mqtt/mqtt-push-parallel.sh

@@ -103,20 +103,24 @@ processInverter () {
     [ "${DATA[12]}" ] && pushMQTTData "$inv_id" "Battery_charge_current"     "${DATA[12]}"
     [ "${DATA[13]}" ] && pushMQTTData "$inv_id" "Battery_capacity"           "${DATA[13]}"
     [ "${DATA[14]}" ] && pushMQTTData "$inv_id" "PV_in_voltage"              "${DATA[14]}"
-    [ "${DATA[25]}" ] && pushMQTTData "$inv_id" "PV_in_current"              "${DATA[25]}"
     [ "${DATA[26]}" ] && pushMQTTData "$inv_id" "Battery_discharge_current"  "${DATA[26]}"
 
-    # ─── PV_in_watts calculation ──────────────────────────────────────────────
-    # DATA[25] = SCC output current at battery-bus voltage (not at PV panel V).
-    # Source: original QPIGS comment "current going out to battery at battery voltage".
-    # Formula: Battery_voltage × DATA[25] = power delivered by SCC to battery.
+    # ─── PV panel-side power calculation ─────────────────────────────────────
+    # DATA[25] is labeled "PV input current" by the inverter but is actually
+    # the SCC *output* current flowing to the battery at battery voltage.
+    # The inverter protocol does NOT expose the real panel-side current directly.
+    #
+    # The SCC is a DC-DC converter: power_in ≈ power_out (ignoring ~5% losses).
+    #   P_pv  = V_batt × I_scc              (SCC output power = panel power)
+    #   I_pv  = P_pv / V_pv                 (real panel current at panel voltage)
     #
     # Edge case - battery fully charged (DATA[25] = 0):
-    # If STATUS b7=1 (SCC_OK) and STATUS b2=1 (line_loss = no AC grid),
-    # solar is feeding the load directly. Use Load_watt as proxy.
-    # If AC grid is present (line_loss=0), solar just floats battery → 0W is correct.
+    #   If SCC_OK (b7=1) and line_loss (b2=1, no AC grid) → solar feeds load directly.
+    #   Best proxy: Load_watt (solar production = what the load is consuming).
+    #   If AC grid is present → solar floats battery, nothing meaningful to report.
     local BATT_V="${DATA[11]:-0}"
     local SCC_A="${DATA[25]:-0}"
+    local PV_V="${DATA[14]:-0}"
     local LOAD_W="${DATA[9]:-0}"
     local STATUS="${DATA[19]:-00000000}"
 
@@ -126,16 +130,31 @@ processInverter () {
     local SCC_OK="${STATUS:0:1}"
     local LINE_LOSS="${STATUS:5:1}"
 
-    local PV_WATTS
+    local PV_WATTS PV_CURRENT
     if awk -v v="$SCC_A" 'BEGIN{exit !(v+0 > 0)}' 2>/dev/null; then
-        # SCC delivering current to battery
+        # SCC delivering current to battery: compute panel-side values
+        # P_pv = V_batt × I_scc
         PV_WATTS=$(echo "$BATT_V $SCC_A" | awk '{printf "%.1f", $1 * $2}')
+        # I_pv = P_pv / V_pv  (real current from panels at panel voltage)
+        if awk -v v="$PV_V" 'BEGIN{exit !(v+0 > 0)}' 2>/dev/null; then
+            PV_CURRENT=$(echo "$PV_WATTS $PV_V" | awk '{printf "%.2f", $1 / $2}')
+        else
+            PV_CURRENT="0.00"
+        fi
     elif [ "$SCC_OK" = "1" ] && [ "$LINE_LOSS" = "1" ]; then
-        # SCC OK, battery full, no AC grid → solar feeds load
+        # SCC OK, battery full, no AC grid → solar feeds load directly
         PV_WATTS="$LOAD_W"
+        if awk -v v="$PV_V" 'BEGIN{exit !(v+0 > 0)}' 2>/dev/null; then
+            PV_CURRENT=$(echo "$PV_WATTS $PV_V" | awk '{printf "%.2f", $1 / $2}')
+        else
+            PV_CURRENT="0.00"
+        fi
     else
         PV_WATTS="0.0"
+        PV_CURRENT="0.00"
     fi
+
+    pushMQTTData "$inv_id" "PV_in_current" "$PV_CURRENT"
     pushMQTTData "$inv_id" "PV_in_watts"   "$PV_WATTS"
 
     # Watt-hours (approximated from polling interval = 30s = 1/120 hour)