From 4fa5c36a096d3609a7150d9f03503d79ad6d90c5 Mon Sep 17 00:00:00 2001
From: Bernhard Kirchen <schlimmchen@posteo.net>
Date: Sat, 30 Nov 2024 20:32:26 +0100
Subject: [PATCH] DPL: cache load-corrected voltage

avoid re-calculation of the load-corrected voltage within the same DPL
loop, as the calculation is quite costly.
---
 include/PowerLimiter.h | 3 +++
 src/PowerLimiter.cpp   | 9 ++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/PowerLimiter.h b/include/PowerLimiter.h
index 79a4c610e..c76b06d34 100644
--- a/include/PowerLimiter.h
+++ b/include/PowerLimiter.h
@@ -91,7 +91,10 @@ class PowerLimiterClass {
     uint16_t getSolarPassthroughPower();
     std::optional<uint16_t> getBatteryDischargeLimit();
     float getBatteryInvertersOutputAcWatts();
+
+    std::optional<float> _oLoadCorrectedVoltage = std::nullopt;
     float getLoadCorrectedVoltage();
+
     bool testThreshold(float socThreshold, float voltThreshold,
             std::function<bool(float, float)> compare);
     bool isStartThresholdReached();
diff --git a/src/PowerLimiter.cpp b/src/PowerLimiter.cpp
index 7a8077ed3..081eb7933 100644
--- a/src/PowerLimiter.cpp
+++ b/src/PowerLimiter.cpp
@@ -259,6 +259,9 @@ void PowerLimiterClass::loop()
 
     _batteryDischargeEnabled = getBatteryPower();
 
+    // re-calculate load-corrected voltage once (and only once) per DPL loop
+    _oLoadCorrectedVoltage = std::nullopt;
+
     if (_verboseLogging && usesBatteryPoweredInverter()) {
         MessageOutput.printf("[DPL] battery interface %sabled, SoC %.1f %% (%s), age %u s (%s)\r\n",
                 (config.Battery.Enabled?"en":"dis"),
@@ -720,6 +723,8 @@ std::optional<uint16_t> PowerLimiterClass::getBatteryDischargeLimit()
 
 float PowerLimiterClass::getLoadCorrectedVoltage()
 {
+    if (_oLoadCorrectedVoltage) { return *_oLoadCorrectedVoltage; }
+
     auto const& config = Configuration.get();
 
     // TODO(schlimmchen): use the battery's data if available,
@@ -731,7 +736,9 @@ float PowerLimiterClass::getLoadCorrectedVoltage()
         return 0.0;
     }
 
-    return dcVoltage + (acPower * config.PowerLimiter.VoltageLoadCorrectionFactor);
+    _oLoadCorrectedVoltage = dcVoltage + (acPower * config.PowerLimiter.VoltageLoadCorrectionFactor);
+
+    return *_oLoadCorrectedVoltage;
 }
 
 bool PowerLimiterClass::testThreshold(float socThreshold, float voltThreshold,