The Unauthorized Guide to iPhone, iPad, and iPod Repair (2013)
Chapter 16. Replacing the Battery
The battery is a good candidate for a Do-It-Yourself (DIY) iDevice repair because Lithium-ion (Li-ion) batteries have a limited number of charge cycles and are therefore replaceable. Of course, Apple does not want customers to replace iDevice batteries themselves. Rather, Apple wants you to turn in your current iDevice for a new model, or pay for a battery replacement.
To that latter point, Apple has a published policy (http://is.gd/i773q6) concerning battery replacements. It works like this:
The default hardware warranty covers the battery for the first year of ownership
The AppleCare Protection Plan covers the battery for the second year of ownership
For out-of-warranty situations, if an Apple Store Genius determines upon inspection that your iDevice’s battery capacity has dropped below the 50 percent mark, he will perform a battery replacement for a fee. The fee schedule is
iPod nano: $59
iPod touch: $79
As you know by now, however, the Apple Store never opens iDevice cases. Thus, you aren’t going to get a battery replacement while you wait. The best you can hope for is either to send in your iDevice to the online Apple Store or hope that the genius at the Genius Bar swaps out your iDevice. In my experience, either outcome is equally likely to occur.
If you’ve read the book in full up to now then you already know the challenges that are inherent in DIY iDevice repair. You can more easily replace the battery on some iDevices than on others.
Before you take your screwdriver and opening tools in hand, however, you need answers to some preliminary questions:
How do Li-ion batteries work, anyway?
Is there any truth to the so-called battery “memory effect”?
What do all the funky markings on iDevice batteries mean?
If nothing else, friends, you can use the information you glean in this chapter to impress your friends at the bar with your deep understanding of iDevice arcana.
What You Need to Know about Lithium-Ion Batteries
Batteries, in general, are devices that store a chemically reactive agent and discharge electrical energy at a fixed rate to power an associated electronic system.
Apple iDevices use Lithium-ion batteries (Li-ion). Li-ion batteries are called secondary batteries because they can be recharged; this is in contrast to primary batteries, which are disposable.
The Li-ion batteries that are present in Apple iDevices are configured in battery packs (also called pouches) that consist of several individual battery cells aligned in parallel. Figure 16.1 shows the battery from an iPhone 4S.
FIGURE 16.1 An iPhone 4S battery.
Caution: Boom, Baby!
Because pure Lithium is very reactive and prone to explosion (more on that later), you need to be careful when you work with iDevice batteries.
What Is the “Memory Effect”?
Many iDevice owners are afraid to recharge their iPods, iPhones, or iPads until their batteries are nearly depleted because they are afraid of the so-called battery “memory effect.”
First, the good news: Li-ion batteries are immune to the memory effect. You are perfectly safe performing partial charges (that is, plugging in the iDevice when the battery has charge left in it).
Second, the “memory effect” was a side effect of older rechargeable batteries, such as nickel-cadmium, in which the battery retains less and less charge over time if it is not allowed to discharge completely.
Apple documents some good battery-related information on its website (http://www.apple.com/batteries/). Specifically, iDevice batteries operate on a “fast charge” principle in which the battery is charged to 80 percent capacity at an accelerated rate, after which the remaining 20 percent is “trickle-charged” at a slower rate. This is a good thing because you can get your depleted iDevices back up and running quickly.
The bad news is that Li-ion batteries have a fixed number of charge cycles before they fail. Apple defines “charge cycle” as a complete charge, from empty to 100 percent capacity.
Over time, you will notice that your iDevice battery capacity gradually decreases. This is normal operation of the battery; even rechargeable batteries are ultimately disposable.
Note: Environmental Hazard
Li-ion batteries present an environmental hazard. Because of this, never simply toss your depleted iDevice into the trash can. Apple itself sponsors an iDevice recycling program; check out the details at http://www.apple.com/recycling/.
Of course, the salient question for is, “How many charge cycles are iDevice batteries good for?” Table 16.1 shows Apple’s published information on battery cycles.
TABLE 16.1 Apple’s Stated Battery Cycles
Let’s now turn our attention to understanding iDevice battery nomenclature. You probably wondered during the iDevice disassemblies, “What do all these crazy specifications printed on the battery pouch actually mean in practice?” It’s now time to get you some answers!
Understanding iDevice Battery Specifications
Take a look at Figure 16.2, which shows the markings on the iPhone 5 battery pouch.
FIGURE 16.2 iPhone 5 battery markings.
From a performance standpoint, the most important specification listed is the milliampere-hour, abbreviated to mAh. The mAh rating of a Li-ion battery denotes its overall capacity. Thus, higher mAh values represent batteries with larger capacities and are therefore preferable to batteries of the same type with lower mAh values.
The mAH rating is comparable to the watt hour (Whr) value. Because there are so many variables at play when attempting to calculate an iDevice’s battery capacity, I’ll leave the mathematics for another book.
As you can see in Figure 16.2, an iOS device battery draws 3.72 volts internally from the standard Apple 5V power adapter.
I want to call your attention also to the iDevice battery’s Apple Part Number (APN) value. APN is the value that you need to track carefully when you purchase a replacement battery for your depleted iDevice.
For the sake of completeness, Table 16.2 lists the Apple-provided battery capacity data for its current iDevice portfolio.
TABLE 16.2 Apple’s Stated iDevice Battery Capacities
Best Practices for iDevice Battery Use
Apple’s published guidelines state that iDevice batteries operate best in a temperature zone from 32° to 95° Fahrenheit. The best practice, of course, is to keep your iDevice at room temperature (approximately 72° F) most of the time.
As mentioned earlier, it’s okay to charge Li-ion batteries in partial cycles rather than doing the “full battery deplete then full recharge” dance that has unfortunately become semi-standard practice among iDevice owners.
To that point, however, Apple suggests “exercising” your battery by depleting it completely and performing a full recharge once per month.
Is it possible to overcharge an iDevice battery? Stated simply, no. Your iDevice simply stops charging when the battery reaches the 100 percent capacity mark.
In iOS 6, you can check our iDevice battery statistics in a variety of ways:
Check out the battery usage indicator in the on-screen status bar
Navigate to Settings, General, Usage, as shown in Figure 16.3
FIGURE 16.3 iOS 6 battery usage (and displaying battery percentage).
Search for battery utilities in the App Store
Search for battery utilities in the Cydia Store (jailbroken iDevices only)
Figure 16.3 shows an example of the Usage screen in iOS 6.
Now, about the “my iPhone battery exploded!” issue. Is there any truth to this claim? Well, yes. The fact of the matter is that the Li-ion polymers that are contained in iDevice battery pouches can be unstable in certain conditions—for instance, if any of the following occurs:
The iDevice is kept in extreme temperatures for extended periods of time.
The owner puts undue pressure on the battery pouch either directly or through the device case.
The electronics of the iDevice contain a manufacturing defect and cause a short or over-charging (and resultant excessive heat) to be produced.
The battery page could indeed swell and perhaps “pop,” bursting the seams of your iDevice and possibly producing smoke and/or sparks.
The iPhone 3GS was known in particular for experiencing this type of battery failure. The salient question, of course, is, “What can I do to limit the possibility of a battery explosion from occurring?”
The answer to that question is, “Give your iDevice the environmental and physical respect it deserves and, barring the aforementioned possibility of an undetected manufacturer’s defect, you should be at low risk for a battery explosion.”
Maximizing Battery Life
To wrap up this section I’ve included a “laundry list” of methods for maximizing the battery life of your iDevice. Most of these tips involve suspending a certain functionality, which should come as no surprise to you.
Turn down screen brightness
Shorten iDevice sleep time
Disable push email
Disable push notifications
Use Airplane Mode
Temporarily disable carrier service
Turn off Bluetooth
Suspend Location Services
Disable data push
Turn off music EQ
Some apps from the Apple or Cydia app stores can provide detailed feedback on battery life savings if you make some of the above tweaks. For instance, check out Battery Doctor in Figure 16.4.
FIGURE 16.4 Battery Doctor is available in the Apple App Store.
Performing Battery Replacements
Let’s gauge the relative ease of iDevice DIY battery replacement by using the simple rating system that I developed, which is shown in Table 16.3. This table also points you to ifixit.com’s instructions for performing battery replacements.
TABLE 16.3 Battery Replacement Difficulty Ratings
Note: Check Back Later
As of this writing, iFixit battery replacement guides for the iPad 4th generation and the iPod touch 5th generation were not yet available. Please check ifixit.com periodically to confirm availability.
It should come as no surprise to you that the iPhones are by far the easiest iDevices to perform battery replacements on. The risk of damaging your iPhone is minimal when undertaking this parts replacement.
Unfortunately, replacing the battery in the iPad or any of the iPods is probably not worth your time and effort unless you are extremely desperate. The iPads, of course, require that you mess with the severely glued-on front panel assemblies. Also, the iPad batteries are themselves glued fast to the rear case.
The iPods are even more nightmarish. Recall that iPod batteries tend to be soldered to the logic board. This means you have to exercise your desoldering and soldering skills to make that repair.
The disassemblies that I provide in this book, when combined with the iFixit links in Table 16.3, should be more than enough information to assist you through most iDevice battery replacements.
That said, I want to present a series of best practice tips for performing successful battery swaps:
Watch those part numbers: You can determine the Li-ion APN by inspecting the outside markings of the battery pouch. You can also obtain your battery APN through the Cydia App Store if you have a jailbroken iDevice; see http://is.gd/PNkSda for a list of available apps.
Carefully select your soldering equipment: For those of you who are brave enough to attempt a battery replacement on an iPod, you need to purchase a soldering iron, desoldering braid, and solder. iFixit sells all of these components, and you are well-advised to purchase their stuff because it has been qualified for iDevice solder jobs. Here are some notes:
Use a 50-watt soldering iron; you don’t want a gun that heats up too much or too little.
Use 1mm rosin core solder with a ~450° F melting point.
Use copper desoldering braid with flux.
Accept the likelihood of cosmetic damage, at least for iPods: As mentioned earlier in this book where I discuss the disassemblies, Apple has gone to great lengths to prevent folks from opening up their iPods. You face an extraordinarily high probability of marring the case of your iPod when you open it (see Figure 16.5). You also gamble with the loss of factory “fit and finish”; this latter problem can be obviated somewhat with the judicious application of 3M adhesive tape to hold the darned thing together.
FIGURE 16.5 iPod nano case damage that occurred during a battery replacement. The two silver objects in the frame are metal case opening tools.