The Battery in the iPhone
This page points to resources on care, maintenance and management of the iPhone battery and how to get as long a battery life as possible.
When and how often should you charge the iPhone battery?
Apple’s article on lithium-ion batteries has the most relevant information that’s specific to the lithium-ion polymer battery in the iPhone. In particular:
“Lithium-ion polymer batteries pack in a higher power density than nickel-based batteries. This gives you a longer battery life in a lighter package, as lithium is the lightest metal. You can also recharge a lithium-ion polymer battery whenever convenient, without the full charge or discharge cycle necessary to keep nickel-based batteries at peak performance. (Over time, crystals build up in nickel-based batteries and prevent you from charging them completely, necessitating an inconvenient full discharge.)”
Also, remember the definition of a charge cycle:
“A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity”.
Refer to the tech specs of the iPhone that’s relevant to your country to understand what the capacity, operating and storage conditions of your particular iPhone battery is.
Apple’s article the iPhone battery
The article says that “paying attention to just a few commonsense pointers will pay off with a longer battery lifespan and battery life for your iPhone”.
Keep the “iPhone out of the sun or a hot car (including the glove box). Heat will degrade your battery’s performance the most”.
The iPhone works best in the 32° to 95° F (0° to 35° C) temperature range.
You should store the iPhone in environments of -4° to 113° F (-20° to 45° C). Ideally, keep the iPhone as near room temperature as possible, that is to say, 72° F or 22° C.
The article then goes on to talk about how to view usage statistics and optimize settings and usage for a longer battery life.
To increase the lifespan of the battery, you’ll need to use the iPhone regularly.
The article stresses that you’ll need to go through “at least one charge cycle per month (charging the battery to 100% and then completely running it down)”.
Replacing the iPhone battery
The following articles by Apple addresses the issue of battery replacement:
- Battery replacement during the standard one-year warranty period, and under the AppleCare Protection Plan for the iPhone. The AppleCare Protection Plan for the iPhone extends the coverage on your device to two years from the original purchase date.
- iPhone Out-of-Warranty Battery Replacement Program - Frequently Asked Questions.
How to prolong lithium-based batteries
This article is not specific to the iPhone battery, but offers some interesting charts on the impact of various factors on the life of a typical lithium-ion battery.
Some of the guidelines in the article are applicable to the iPhone battery:
- Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.
- Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.
- Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level.