package main.flowstoneenergy.items.battery;

import main.flowstoneenergy.ModInfo;

public class ItemBatteryFlowstoneTierFour extends ItemBatteryFlowstoneTierOne {
	public ItemBatteryFlowstoneTierFour() {
		super();
		this.setTextureName(ModInfo.MODID + ":batteries/tierFour");
		this.setUnlocalizedName(ModInfo.MODID + ".flowstone.battery.tier.four");
		this.setMaxStackSize(1);
	}
}

package main.flowstoneenergy.items.battery;

import main.flowstoneenergy.ModInfo;

public class ItemBatteryFlowstoneTierFour extends ItemBatteryFlowstoneTierOne {
	
	private int maxFE = 100000;
	public int currentFE = 0;
	
	public ItemBatteryFlowstoneTierFour() {
		super();
		this.setTextureName(ModInfo.MODID + ":batteries/tierFour");
		this.setUnlocalizedName(ModInfo.MODID + ".flowstone.battery.tier.four");
		this.setMaxStackSize(1);
	}
	
	@SuppressWarnings({ "rawtypes", "unchecked" })
	@Override
	public void addInformation(ItemStack stack, EntityPlayer player, List list, boolean par4) {
		list.add(TextHelper.shiftForMoreInfo);
    	if (!KeyboardHelper.isShiftDown()) {
			return;
		}
    	list.remove(1);
		list.add(currentFE + "/" + maxFE + "FE Stored");
		list.add("RIGHT CLICK to activate");
	}
}

Update ItemBatteryFlowstoneTierFour.java