- Disassembly Overview
- Electrostatic Discharge (ESD)
- EMI (Electromagnetic Interference)
- Disassembly
- Tools
- Opening the Case
- Cables and Connectors
- Storage Devices
- Motherboards
- Mobile Device Issues
- Reassembly
- Preventive Maintenance
- Basic Electronics Overview
- Electronics Terms
- Power Supply Overview
- Power Supply Form Factors
- Purposes of a Power Supply
- Power Supply Voltages
- Mobile Device Travel and Storage
- Mobile Device Power
- ACPI (Advanced Configuration and Power Interface)
- Replacing or Upgrading a Power Supply
- Symptoms of Power Supply Problems
- Solving Power Supply Problems
- Adverse Power Conditions
- Adverse Power Protection
- Surge Protectors
- Line Conditioners
- Uninterruptible Power Supply (UPS)
- Standby Power Supply (SPS)
- Phone Line Isolator
- Electrical Fires
- Computer Disposal/Recycling
- Soft Skills?Written Communications Skills
- Chapter Summary
- Key Terms
- Review Questions
- Exercises
- Activities
This chapter is from the book
This chapter is from the book
This chapter is from the book
Mobile Device Power
A portable computer (laptop/netbook/ultrabook/tablet) uses either an AC connection or a battery as its power source. On most models, when the mobile device connects to AC power, the battery normally recharges. Laptop batteries are usually modules with one or two release latches that are used to remove the module. Smartphone batteries either have a release latch or you slide part of the phone away and reveal the battery. Figure 4.27 shows a netbook computer with its battery module removed. Battery technologies have improved in the past few years, probably due to the development of more devices that need battery power, such as tablets, digital cameras, and portable CD, DVD, and BD players.
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Figure 4.27. Netbook battery
TECH TIP: Check input voltage selector
Some power supplies and laptops have input voltage selectors; others have the ability to accept input from 100 to 240 volts for use in various countries (dual voltage). Ensure that the power supply accepts or is set to the proper input voltage.
NiCad (nickel cadmium) batteries originally used in laptops were replaced with lighter and more powerful NiMH (nickel-metal hydride) batteries. These batteries were replaced with Li-ion (lithium-ion) batteries, which are very light and can hold a charge longer than any other type. They are also more expensive. Mobile phones, tablets, portable media players, and digital cameras also use Li-ion batteries. These batteries lose their charge over time even if they are not being used. Use your laptop with battery-provided power. Ensure that a laptop that has an Li-ion battery is not plugged into an AC outlet all the time. Calibrate a laptop battery according to manufacturer instructions so the battery meter displays correctly.
TECH TIP: Do not power on after a temperature change
Computers are designed to work within a range of temperatures, but sudden change is not good for them. If a mobile device is in a car all night and the temperature drops, allow the device to return to room temperature before powering on. Avoid direct sunlight. Inside the computer case, it is usually 40°F hotter than outside.
Li-ion polymer batteries are similar to Li-ion batteries except that they are packed in pouched cells. This design allows for smaller batteries and a more efficient use of space, which is important in the portable computer and mobile devices industries. For environmentalists, the zinc-air battery is the one to watch. AER Energy Resources, Inc., has several patents on a battery that uses oxygen to generate electricity. Air is allowed to flow during battery discharge and is blocked when the battery is not in use. This battery holds a charge for extended periods of time. Another upcoming technology is fuel cells. Fuel cells used for a laptop can provide power for 5 to 10 hours.
TECH TIP: Do not fully discharge a Li-ion battery
Li-ion batteries do not suffer from the memory effect, as do some nickel-based batteries. Fully discharging a lithium battery, such as an Li-ion battery, is actually bad for it. However, most lithium batteries have a circuit to prevent the battery from being totally discharged.
TECH TIP: Keep Li-ion batteries cool
Li-ion batteries last longer if they are kept cool (not frozen). When you store an Li-ion battery, the battery should be only 40 percent charged and placed in a refrigerator to prolong its life.
Mobile devices rely on their batteries to provide the mobility. The following tips can help you get more time out of your batteries:
- Most people do not need a spare Li-ion battery. If you are not using an Li-ion battery constantly, it is best not to buy a spare. The longer the spare sits unused, the shorter the lifespan it will have.
- Buy the battery recommended by the laptop manufacturer.
- For a mobile device or smartphone, use an AC outlet rather than a USB port for faster charging.
- If using a USB port for charging a mobile device or smartphone, unplug all unused USB devices. Note that not all USB ports can provide a charge if the host device is in sleep mode.
- Do not use the optical player when running on battery power.
- Turn off the wireless adapter if a wireless network is not being used. For Windows-based devices, use the Network and Internet Control Panel. For smaller mobile devices, use flight mode to turn off both the wireless and the cellular (3G/4G) networks. Apple iOS devices can use Settings to access Airplane Mode. Android devices can use the Settings option to access Flight mode through the Wireless and network option.
- In the power options, configure the mobile device for hibernate rather than standby (covered later in the chapter).
- Save work only when necessary and turn off the autosave feature.
- Reduce the screen brightness. In Windows, use the Display Control Panel link found within the Hardware and Sound Control Panel. In Apple iOS, us the Brightness & Wallpaper setting; on an Android device, use the Sound and display option from the Settings application.
- Keep the hard drive defragmented especially before running on battery power.
- Avoid using external USB devices such as flash drives or external hard drives.
- Add more RAM to reduce swapping of information from the hard drive to RAM to CPU or to just be more efficient.
- Keep battery contacts clean with a dab of rubbing alcohol on a lint-free swab once a month.
- Use your mobile device until the battery is drained when possible and then recharge it. Constantly recharging the battery reduces the battery life. Most lithium batteries have a circuit that keeps the battery from being discharged completely.
- Avoid running multiple programs. To close an application on an iOS-based device, hold down on the icon from the home menu. On an Android-based device, use the Applications > Manage Applications option from the Settings application.
- Disable automatic updates. In Windows, use the Windows Update link from the System and Security Control Panel. On iOS or Android systems, disable push reports and application notifications that make sounds or vibrations from within the Settings option. Have the OS check less often for mail; use the Mail, Contacts, Calendars option to change the settings.
- Avoid temperature extremes.
TECH TIP: All power supplies are not created equal
A technician needs to replace a power supply with one that provides an equal or greater amount of power. Search the Internet for power supply reviews. A general rule of thumb is that if two power supplies are equal in wattage, the heavier one is better because it uses a bigger transformer, bigger heat sinks, and more quality components.