Check if there are batteries before checking if they are charging

src/battery.cpp

@@ -151,6 +151,7 @@ float BatteryStats::getPower(int batt_num) {
 }
 
 bool BatteryStats::isCharging() {
+    if (numBattery() > 0) {
         for(int i =0; i < 2; i++) {
             string syspath = battPath[i];
             string status = syspath + "/status";
@@ -167,11 +168,12 @@ bool BatteryStats::isCharging() {
             return true;
             }
         }
+    }
 
     return false;
-
 }
 
+
 bool BatteryStats::fullCharge(){
     //check if both batteries are fully charged
     int charged =0;