Fix: solar: base maxTotalIncrease on currentLimit

We used currentOutputAc before which could result in us thinking that we can go even higher even though the limit was already at the maximum.

src/PowerLimiterSolarInverter.cpp

@@ -24,8 +24,11 @@ uint16_t PowerLimiterSolarInverter::getMaxIncreaseWatts() const
         return getConfiguredMaxPowerWatts();
     }
 
-    // the maximum increase possible for this inverter
-    int16_t maxTotalIncrease = getConfiguredMaxPowerWatts() - getCurrentOutputAcWatts();
+    // we must not substract the current AC output here, but the current
+    // limit value, so we avoid trying to produce even more even if the
+    // inverter is already at the maximum limit value (the actual AC
+    // output may be less than the inverter's current power limit).
+    int16_t maxTotalIncrease = getConfiguredMaxPowerWatts() - getCurrentLimitWatts();
 
     if (isSmartBufferPowered()) {
         // smart buffer inverters can always increase the power to the configured max