diff --git a/src/main/java/de/mrgeorgen/v2g/car.java b/src/main/java/de/mrgeorgen/v2g/car.java
index 9f92694..b63f080 100644
--- a/src/main/java/de/mrgeorgen/v2g/car.java
+++ b/src/main/java/de/mrgeorgen/v2g/car.java
@@ -2,8 +2,8 @@ package de.mrgeorgen.v2g;
 
 public class car {
 	private final int id;
-	private final carTemplate carModel;
-	private int battery;
+	public final carTemplate carModel;
+	public int battery;
 	private int chargeLock;
 
 	public car(carTemplate carModel, int id) { // id can be the same for different models
@@ -12,15 +12,15 @@ public class car {
 		this.id = id;
 		this.battery = this.carModel.fullBattery / 2;
 	}
-	public void charge() {
-		int chargeAmmount = Math.abs(powerGrid.energieAvailable) < this.carModel.chargeSpeed ? powerGrid.energieAvailable : powerGrid.energieAvailable > 0 ? this.carModel.chargeSpeed : -1 * this.carModel.chargeSpeed;
+	public int charge(int maxCharge) {
+		int chargeAmmount = Math.abs(maxCharge) < this.carModel.chargeSpeed ? maxCharge : maxCharge > 0 ? this.carModel.chargeSpeed : -1 * this.carModel.chargeSpeed;
 		if(this.battery + chargeAmmount <= this.chargeLock && chargeAmmount < 0) chargeAmmount = (this.battery - this.chargeLock) * -1; // do not charge if the car gets under the charge lock
 		if(this.battery + chargeAmmount > this.carModel.fullBattery) chargeAmmount = this.carModel.fullBattery - this.battery; // prevent the battery from overcharging
 		if(this.battery + chargeAmmount < 0) chargeAmmount = this.battery * -1; // prevent the battery from dischargingunder 0%
 		if(chargeAmmount != 0) System.out.println(this.carModel.model + " nr. " + this.id + " is " + (chargeAmmount < 0 ? "dis" : "") + "charging with " + (double)Math.abs(chargeAmmount) / 1000 +  " kW. battery: " + (double)this.battery / 1000 + "/" + (double)this.carModel.fullBattery / 1000 + " kWh (" + Math.round(getBatteryRelativ() * 100) + "%)");
 		this.battery += chargeAmmount;
-		powerGrid.energieAvailable -= chargeAmmount;
 		if(chargeAmmount < 0) powerGrid.savedEnergie += Math.abs(chargeAmmount);
+		return chargeAmmount;
     	}
 	private void setChargeLock(double chargeLock) {
 		this.chargeLock = (int)(this.carModel.fullBattery * chargeLock);
diff --git a/src/main/java/de/mrgeorgen/v2g/carGrid.java b/src/main/java/de/mrgeorgen/v2g/carGrid.java
index 1b730f3..5a09b58 100644
--- a/src/main/java/de/mrgeorgen/v2g/carGrid.java
+++ b/src/main/java/de/mrgeorgen/v2g/carGrid.java
@@ -1,10 +1,14 @@
 package de.mrgeorgen.v2g;
+import java.lang.Double;
 import java.util.ArrayList;
-import java.util.Random;
 import java.util.Collections;
 import java.util.Comparator;
-import java.lang.Double;
+import java.util.Random;
+
+import de.mrgeorgen.v2g.car;
+import de.mrgeorgen.v2g.carGrid;
 public class carGrid {
+	public int energieAvailable;
 	public ArrayList<car> dockedCars = new ArrayList<car>();
 	private final carTemplate[] models = {new carTemplate("Tesla Model 3", 50, 160, 335),
 	new carTemplate("Renault Zoe ZE50", 52, 46, 315),
@@ -14,16 +18,17 @@ public class carGrid {
 	new carTemplate("Tesla Model S Long Range", 90, 250, 555),
 	new carTemplate("Smart EQ forfour", 17, 5, 95),
 	new carTemplate("Honda e", 29, 56, 170)};
-	public void fillWithCars() {
+	public carGrid() {
 		Random random = new Random();
 		for(carTemplate carModel : models) {
 			final int numberOfCars = random.nextInt(10);
 			for(int i = 0; i < numberOfCars; ++i) {
-				dockedCars.add(new car(carModel, i));
+				final car car = new car(carModel, i); 
+				dockedCars.add(car);
 			}
 		}
 	}
-	public void chargeCars() {
+	public int chargeCars(int maxCharge) {
 		Collections.sort(dockedCars, new Comparator<car>() {
 			public int compare(car car1, car car2) {
 				Double car1RelativBattery = car1.getBatteryRelativ();
@@ -31,11 +36,25 @@ public class carGrid {
 				return car1RelativBattery.compareTo(car2RelativBattery);
 			}
 		});
-		if(powerGrid.energieAvailable < 0) Collections.reverse(dockedCars);
-		dockedCars.forEach((car car) -> {
-			car.charge();
-		});
-		if(powerGrid.energieAvailable > 0) System.out.println(powerGrid.energieAvailable + " W could not be used by the cars");
-		else if(powerGrid.energieAvailable < 0) System.out.println(Math.abs(powerGrid.energieAvailable) + " W could not be taken from the cars");
+		if(maxCharge < 0) Collections.reverse(dockedCars);
+		int charged = 0;
+		for(car car : dockedCars) {
+			charged += car.charge(maxCharge - charged);
+		}
+		return charged;
+	}
+	public int capacityDockedCars() {
+		int maxBattery = 0;
+		for(car car : dockedCars) {
+			maxBattery += car.carModel.fullBattery;
+		}
+		return maxBattery;
+	}
+	public double relativeChargeState() {
+		int battery = 0;
+		for(car car : dockedCars) {
+			battery += car.battery;
+		}
+		return ((double)battery + energieAvailable) / capacityDockedCars();
 	}
 }
diff --git a/src/main/java/de/mrgeorgen/v2g/powerGrid.java b/src/main/java/de/mrgeorgen/v2g/powerGrid.java
index 1547a93..cd87f87 100644
--- a/src/main/java/de/mrgeorgen/v2g/powerGrid.java
+++ b/src/main/java/de/mrgeorgen/v2g/powerGrid.java
@@ -1,30 +1,50 @@
 package de.mrgeorgen.v2g;
 import java.util.Random;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.lang.Math;
 public class powerGrid {
 	public static int energieAvailable;
 	public static int savedEnergie;
+	private static ArrayList<car> allCars = new ArrayList<car>();
+	private static ArrayList<carGrid> carGrids = new ArrayList<carGrid>();
 	public static void main(String args[]) {
 		if(args.length != 1) {
 			System.out.println("Invalid Syntax. Use the number of days the simulation shell run as the first argument");
 			return;
 		}
-		final carGrid carGrid = new carGrid();
-		carGrid.fillWithCars();
-		car[] allCars = new car[carGrid.dockedCars.size()];
-		allCars = carGrid.dockedCars.toArray(allCars);
-		final int hourSimulationRuns = Integer.parseInt(args[0]) * 24;
 		Random random = new Random();
+		final int numberOfCarGrids = 2 + random.nextInt(10);
+		for(int i = 0; i < numberOfCarGrids; ++i) {
+			final carGrid carGrid = new carGrid();
+			carGrids.add(carGrid);
+			allCars.addAll(carGrid.dockedCars);
+		}
+		final int hourSimulationRuns = Integer.parseInt(args[0]) * 24;
 		for(int houresPassed = 0; houresPassed < hourSimulationRuns; ++houresPassed) {
 			final int hourOfDay = houresPassed % 24;
 			System.out.println("Day " + houresPassed / 24 + " Hour " + hourOfDay);
 			int averageEnergie;
-			if(hourOfDay < 6 || hourOfDay > 22) averageEnergie = carGrid.dockedCars.size() * 3000; // energie available at night
-			else if(hourOfDay < 7) averageEnergie = carGrid.dockedCars.size() * -1000; // energie for light in the morning
-			else if(hourOfDay < 19) averageEnergie = carGrid.dockedCars.size() * -500; // at the day energie is still needed but not as much because the lights are not on
-			else /* hourOfDay > 19 && hourOfDay < 23 */ averageEnergie = carGrid.dockedCars.size() * -1000; // the lights are on again
+			if(hourOfDay < 6 || hourOfDay > 22) averageEnergie = allCars.size() * 3000; // energie available at night
+			else if(hourOfDay < 7) averageEnergie = allCars.size() * -1000; // energie for light in the morning
+			else if(hourOfDay < 19) averageEnergie = allCars.size() * -500; // at the day energie is still needed but not as much because the lights are not on
+			else /* hourOfDay > 19 && hourOfDay < 23 */ averageEnergie = allCars.size() * -1000; // the lights are on again
 			energieAvailable = (int)(averageEnergie * (0.5 + 1.5 * random.nextDouble()));
-			carGrid.chargeCars();
+			Collections.sort(carGrids, new Comparator<carGrid>() {
+				public int compare(carGrid carGrid1, carGrid carGrid2) {
+					Double carGrid1RelativChargeState = carGrid1.relativeChargeState();
+					Double carGrid2RelativBattery = carGrid2.relativeChargeState();
+					return carGrid1RelativChargeState.compareTo(carGrid2RelativBattery);
+				}
+			});
+			if(energieAvailable < 0) Collections.reverse(carGrids);
+			for(carGrid carGrid : carGrids) {
+				energieAvailable -= carGrid.chargeCars(energieAvailable);
+			}
+			if(energieAvailable > 0) System.out.println(energieAvailable + " W could not be used by the cars");
+			else if(energieAvailable < 0) System.out.println(Math.abs(energieAvailable) + " W could not be taken from the cars");
 		}
-		System.out.println("vehicle to grid saved " + (double)savedEnergie / 1000 + " kWh with " + carGrid.dockedCars.size() + " cars");
+		System.out.println("vehicle to grid saved " + (double)savedEnergie / 1000 + " kWh with " + allCars.size() + " cars");
 	}
 }