[Xperia Arc Q&A, Help & Troubleshooting] soxxo:
Decompile systemui.apk and navigate to SystemUI/res/layout/status_bar.xml and find this line:

<LinearLayout android:gravity="center" android:orientation="horizontal" android:id="@id/signal_battery_cluster" android:paddingLeft="2.0dip" android:layout_width="wrap_content" android:layout_height="fill_parent">
<include android:id="@id/signal_cluster" android:layout_width="wrap_content" android:layout_height="wrap_content" layout="@layout/signal_cluster_view" />
<ImageView android:id="@id/battery" android:paddingLeft="4.0dip" android:layout_width="wrap_content" android:layout_height="wrap_content" />
</LinearLayout>

And add red line below:

<LinearLayout android:gravity="center" android:orientation="horizontal" android:id="@id/signal_battery_cluster" android:paddingLeft="2.0dip" android:layout_width="wrap_content" android:layout_height="fill_parent">
<include android:id="@id/signal_cluster" android:layout_width="wrap_content" android:layout_height="wrap_content" layout="@layout/signal_cluster_view" />
[COLOR="Red"]<TextView android:layout_gravity="left|center" android:id="@id/battery_text" android:paddingLeft="4.0dip" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/status_bar_settings_settings_button" android:singleLine="true" style="@style/StatusBarNotificationText" />[/COLOR]
<ImageView android:id="@id/battery" android:paddingLeft="4.0dip" android:layout_width="wrap_content" android:layout_height="wrap_content" />
</LinearLayout>

Save change you have made. After that, look for this smali file:

PhoneStatusBar.smali

.line 358
iget-object v10, p0, Lcom/android/systemui/statusbar/phone/PhoneStatusBar;->mBatteryController:Lcom/android/systemui/statusbar/policy/BatteryController;

const v9, 0x7f0e0028

invoke-virtual {v4, v9}, Lcom/android/systemui/statusbar/phone/PhoneStatusBarView;->findViewById(I)Landroid/view/View;

move-result-object v9

check-cast v9, Landroid/widget/ImageView;

invoke-virtual {v10, v9}, Lcom/android/systemui/statusbar/policy/BatteryController;->addIconView(Landroid/widget/ImageView;)V

and add red lines below:

.line 358
iget-object v10, p0, Lcom/android/systemui/statusbar/phone/PhoneStatusBar;->mBatteryController:Lcom/android/systemui/statusbar/policy/BatteryController;

const v9, 0x7f0e0028

invoke-virtual {v4, v9}, Lcom/android/systemui/statusbar/phone/PhoneStatusBarView;->findViewById(I)Landroid/view/View;

move-result-object v9

check-cast v9, Landroid/widget/ImageView;

invoke-virtual {v10, v9}, Lcom/android/systemui/statusbar/policy/BatteryController;->addIconView(Landroid/widget/ImageView;)V

[COLOR="Red"].line 13
iget-object v10, p0, Lcom/android/systemui/statusbar/phone/PhoneStatusBar;->mBatteryController:Lcom/android/systemui/statusbar/policy/BatteryController;

const v9, 0x7f0e0061

invoke-virtual {v4, v9}, Lcom/android/systemui/statusbar/phone/PhoneStatusBarView;->findViewById(I)Landroid/view/View;

move-result-object v9

check-cast v9, Landroid/widget/TextView;

invoke-virtual {v10, v9}, Lcom/android/systemui/statusbar/policy/BatteryController;->addLabelView(Landroid/widget/TextView;)V[/COLOR]

also change the const v9, 0x7f0e0061 to your own value, look for it inside public.xml

Recompile back.