Twizy-ChargeThrottle V1.0 (initial release)

.gitignore

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+assets
+*.html

README.md

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+# TwizyChargeThrottle
+
+This is a very simple tool to limit the Twizy charge current if you don't have an OVMS.
+
+It can currently only limit the charge current to a fixed level (defined in the config file).
+
+The Arduino needs to be connected to the Twizy CAN bus during the charge process to be able
+to actively overwrite the charge current control frames.
+
+Note: using an interrupt capable CAN shield is highly recommended.
+
+
+## Info
+
+Author: Michael Balzer <dexter@dexters-web.de>
+
+Libraries used:
+  - MCP_CAN: https://github.com/coryjfowler/MCP_CAN_lib
+
+This is free software under GNU Lesser General Public License (LGPL)
+https://www.gnu.org/licenses/lgpl.html

TwizyChargeThrottle/TwizyChargeThrottle.ino

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+/**
+ * ==========================================================================
+ * Twizy charge current throttle
+ * ==========================================================================
+ * 
+ * Author: Michael Balzer <dexter@dexters-web.de>
+ * 
+ * Libraries used:
+ *  - MCP_CAN: https://github.com/coryjfowler/MCP_CAN_lib
+ * 
+ * License:
+ *  This is free software under GNU Lesser General Public License (LGPL)
+ *  https://www.gnu.org/licenses/lgpl.html
+ *  
+ */
+#define TWIZY_CT_VERSION "V1.0 (2019-05-10)"
+
+#include <mcp_can.h>
+#include <mcp_can_dfs.h>
+#include "TwizyChargeThrottle_config.h"
+
+// CAN interface:
+MCP_CAN CAN(TWIZY_CAN_CS_PIN);
+
+// CAN msg buffer:
+unsigned long msgId;
+byte msgLen;
+byte msgBuf[8];
+
+// Operation mode:
+bool charging = false;
+
+// Current level:
+byte level = 0;
+
+
+#if TWIZY_CAN_IRQ_PIN > 0
+volatile bool msgReceived = false;
+void canISR() {
+  msgReceived = true;
+}
+#endif
+
+
+void setup() {
+
+  Serial.begin(SERIAL_SPEED);
+  Serial.println(F("TwizyChargeThrottle " TWIZY_CT_VERSION));
+
+  // Init CAN interface:
+
+  #if TWIZY_CAN_IRQ_PIN > 0
+  pinMode(TWIZY_CAN_IRQ_PIN, INPUT);
+  attachInterrupt(digitalPinToInterrupt(TWIZY_CAN_IRQ_PIN), canISR, FALLING);
+  #endif
+
+  while (CAN.begin(MCP_STDEXT, CAN_500KBPS, TWIZY_CAN_MCP_FREQ) != CAN_OK) {
+    Serial.println(F("Setup: waiting for CAN connection..."));
+    delay(1000);
+  }
+
+  // Set ID filters:
+
+  CAN.init_Mask(0, 0, 0x07FF0000);
+  CAN.init_Filt(0, 0, 0x01550000); // BMS → BMS: current control
+  CAN.init_Filt(1, 0, 0x05970000); // CHG → BMS: operation mode
+
+  CAN.init_Mask(1, 0, 0x07FF0000);
+  CAN.init_Filt(2, 0, 0x00000000);
+  CAN.init_Filt(3, 0, 0x00000000);
+  CAN.init_Filt(4, 0, 0x00000000);
+  CAN.init_Filt(5, 0, 0x00000000);
+
+  CAN.setMode(MCP_NORMAL);
+
+  Serial.println(F("Setup done."));
+
+  Serial.print(F("Throttling configured to current level: "));
+  Serial.println((char)('0' + TWIZY_CHARGE_THROTTLE));
+}
+
+
+void loop() {
+  while (true) {
+
+    #if TWIZY_CAN_IRQ_PIN > 0
+    // Wait for interrupt signal:
+    while (!msgReceived);
+    msgReceived = false;
+    #endif
+
+    // Process CAN read buffer:
+    while (CAN.readMsgBuf(&msgId, &msgLen, msgBuf) == CAN_OK)
+    {
+      if (msgId == 0x597)
+      {
+        // ID 0x597: operation mode
+
+        bool _charging = ((msgBuf[1] & 0x60) == 0x20);
+
+        #if TWIZY_DEBUG > 0
+        if (_charging && !charging)
+          Serial.println(F("Charge START"));
+        else if (!_charging && charging)
+          Serial.println(F("Charge STOP"));
+        #endif
+
+        charging = _charging;
+        level = 0;
+      }
+      else if (charging)
+      {
+        // ID 0x155: charge current control
+
+        byte _level = msgBuf[0];
+
+        if (_level == 0xFF)
+          continue; // init phase, skip
+
+        if (_level > TWIZY_CHARGE_THROTTLE)
+        {
+          // overwrite:
+          msgBuf[0] = TWIZY_CHARGE_THROTTLE;
+          CAN.sendMsgBuf(0x155, 0, 8, msgBuf);
+        }
+
+        #if TWIZY_DEBUG > 1
+        if (_level != level)
+        {
+          Serial.print(F("Level "));
+          if (_level > TWIZY_CHARGE_THROTTLE) {
+            Serial.print((char)('0' + _level));
+            Serial.print('>');
+            Serial.println((char)('0' + TWIZY_CHARGE_THROTTLE));
+          } else {
+            Serial.println((char)('0' + _level));
+          }
+        }
+        #endif
+
+        level = _level;
+      }
+    }
+
+  } // while (true)
+}
+

TwizyChargeThrottle/TwizyChargeThrottle_config.h

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+/**
+ * ==========================================================================
+ * Twizy charge current throttle
+ * ==========================================================================
+ */
+#ifndef _TwizyChargeThrottle_config_h
+#define _TwizyChargeThrottle_config_h
+
+// Set the charge current throttle level here:
+//  6 = 30 A = 2,1 kW
+//  5 = 25 A = 1,7 kW
+//  4 = 20 A = 1,4 kW
+//  3 = 15 A = 1,0 kW
+//  2 = 10 A = 0,7 kW
+//  1 =  5 A = 0,4 kW
+#define TWIZY_CHARGE_THROTTLE     5
+
+// Serial debug output level:
+//  1 = show charge start/stop
+//  2 = show current level changes
+#define TWIZY_DEBUG               2
+
+// Serial interface baud rate:
+#define SERIAL_SPEED              115200
+
+// Set your CAN MCP clock frequency here:
+#define TWIZY_CAN_MCP_FREQ        MCP_16MHZ
+
+// Set your CAN CS pin number here:
+#define TWIZY_CAN_CS_PIN          SS
+
+// Set your CAN IRQ pin here (0 = no IRQ):
+#define TWIZY_CAN_IRQ_PIN         2
+
+#endif // _TwizyChargeThrottle_config_h
+