Refixed the CBC error found by @VinceKezel

Signed-off-by: Sara Damiano <sdamiano@stroudcenter.org>

src/TinyGsmClientA6.h

@@ -401,6 +401,7 @@ class TinyGsmA6
  protected:
   uint16_t getBattVoltageImpl() TINY_GSM_ATTR_NOT_AVAILABLE;
 
+  // Needs a '?' after CBC, unlike most
   int8_t getBattPercentImpl() {
     sendAT(GF("+CBC?"));
     if (waitResponse(GF(GSM_NL "+CBC:")) != 1) { return false; }
@@ -412,6 +413,7 @@ class TinyGsmA6
     return res;
   }
 
+  // Needs a '?' after CBC, unlike most
   bool getBattStatsImpl(uint8_t& chargeState, int8_t& percent,
                         uint16_t& milliVolts) {
     sendAT(GF("+CBC?"));

src/TinyGsmClientSIM5360.h

@@ -438,6 +438,7 @@ class TinyGsmSim5360 : public TinyGsmModem<TinyGsmSim5360, READ_AND_CHECK_SIZE,
    * Battery & temperature functions
    */
  protected:
+  // SRGD Note:  Returns voltage in VOLTS instead of millivolts
   uint16_t getBattVoltageImpl() {
     sendAT(GF("+CBC"));
     if (waitResponse(GF(GSM_NL "+CBC:")) != 1) { return 0; }
@@ -452,9 +453,10 @@ class TinyGsmSim5360 : public TinyGsmModem<TinyGsmSim5360, READ_AND_CHECK_SIZE,
     return res;
   }
 
+  // SRGD Note:  Returns voltage in VOLTS instead of millivolts
   bool getBattStatsImpl(uint8_t& chargeState, int8_t& percent,
                         uint16_t& milliVolts) {
-    sendAT(GF("+CBC?"));
+    sendAT(GF("+CBC"));
     if (waitResponse(GF(GSM_NL "+CBC:")) != 1) { return false; }
     chargeState = stream.readStringUntil(',').toInt();
     percent     = stream.readStringUntil(',').toInt();

src/TinyGsmClientSIM7600.h

@@ -445,7 +445,7 @@ class TinyGsmSim7600 : public TinyGsmModem<TinyGsmSim7600, READ_AND_CHECK_SIZE,
    * Battery & temperature functions
    */
  protected:
-  // Use: float vBatt = modem.getBattVoltage() / 1000.0;
+  // returns volts, multiply by 1000 to get mV
   uint16_t getBattVoltageImpl() {
     sendAT(GF("+CBC"));
     if (waitResponse(GF(GSM_NL "+CBC:")) != 1) { return 0; }

src/TinyGsmCommon.h

@@ -1136,7 +1136,7 @@ class TinyGsmModem {
   }
 
   uint8_t getBattChargeStateImpl() {
-    thisModem().sendAT(GF("+CBC?"));
+    thisModem().sendAT(GF("+CBC"));
     if (thisModem().waitResponse(GF("+CBC:")) != 1) { return false; }
     // Read battery charge status
     int res = thisModem().stream.readStringUntil(',').toInt();
@@ -1147,7 +1147,7 @@ class TinyGsmModem {
 
   bool getBattStatsImpl(uint8_t& chargeState, int8_t& percent,
                         uint16_t& milliVolts) {
-    thisModem().sendAT(GF("+CBC?"));
+    thisModem().sendAT(GF("+CBC"));
     if (thisModem().waitResponse(GF("+CBC:")) != 1) { return false; }
     chargeState = thisModem().stream.readStringUntil(',').toInt();
     percent     = thisModem().stream.readStringUntil(',').toInt();