前幾天提到 Apple 在新版 iOS 上搞出的電池問題：「iPhone 換電池恢復效能的事情傳到 Geekbench 後...」，結果看起來是 PR 部門整個加班處理 XDDD
台灣版的公告在「致廣大顧客關於 iPhone 電池與效能的說明」這邊可以看到，英文版的則是在「A Message to Our Customers about iPhone Batteries and Performance」這邊。
- Apple 為需要更換電池的 iPhone 6 或後續機種使用者，降低更換已過保固期的 iPhone 電池價格，從 NT$2,590 降為 NT$890，降幅為 NT$1,700。自 2018 年 1 月底至 12 月，全球同步進行。詳細優惠資訊將在近期於 apple.com/tw 公布。
- 在 2018 年初，我們將發布一項 iOS 軟體更新，其中的新功能可為使用者更清楚顯示 iPhone 電池的健康狀態，讓他們可以自己看到電池的狀態是否影響效能。
- Apple is reducing the price of an out-of-warranty iPhone battery replacement by $50 — from $79 to $29 — for anyone with an iPhone 6 or later whose battery needs to be replaced, starting in late January and available worldwide through December 2018. Details will be provided soon on apple.com.
- Early in 2018, we will issue an iOS software update with new features that give users more visibility into the health of their iPhone’s battery, so they can see for themselves if its condition is affecting performance.
所以總算是能在 iPhone 上面直接看到電池的情況了...
在「iPhone 的電池與效能」這篇提到了 iPhone 換電池可以恢復效能，結果 Geekbench (也就是原來在 Reddit 上抱怨的人用的測速軟體) 的 John Poole 從 Geekbench 的回報資料庫裡分析了資料，發現了特別的現象後寫下這篇文章 (於是後來引發一連串報導，以及 Apple 的 PR 事件)：「iPhone Performance and Battery Age」。
他先拿 iPhone 6S 分析，這看起來就不太妙：
再拿 iPhone 7 的資料分析，就更確定不妙：
可以看到 iOS 的 10.2.1 與 11.2.0 有奇怪的效能集中區。
後續蘋果也確認會刻意降速：「Apple addresses why people are saying their iPhones with older batteries are running ‘slower’」。
然後最新的發展就不太意外了，開始要打架了：「Days after iPhone battery fiasco, lawsuits against Apple begin to mount」。
在 Hacker News 上看到 Reddit 上的這則說明：「PSA: iPhone slow? Try replacing your battery!」。
他提到他的 iPhone 6S 很慢，本來以為是 iOS 11 導致的，結果發現他弟弟 (或是哥哥？) 的 iPhone 6 也是跑 iOS 11，但是快很多... 所以他就試著研究，最後決定換電池：
My iPhone 6S has been very slow these past few weeks, and even after updating multiple times, it was still slow. Couldn’t figure out why, but just thought that iOS 11 was still awful to me. Then I used my brother’s iPhone 6 Plus and his was... faster than mine? This is when I knew something was wrong. So, I did some research, and decided to replace my battery.
在 iOS 上測試的軟體是 Geekbench 4，而官方也有給參考值 (Geekbench 的)，在 iOS Benchmarks - Geekbench Browser 可以參考。如果在吃滿電、重開機，沒有背景的情況下還是很慢的話，有機會是類似的問題？
在「Lithium-ion batteries banned as cargo on passenger planes」這篇文章裡面提到美國打算在今年四月開始禁止托運含有鋰電池的設備：
Due to the risk of fire, lithium-ion batteries cannot be shipped as cargo on passenger planes.
That's according to a new ban enacted by the U.N.'s International Civil Aviation Organization, which takes effect in April.
如同文章尾提到的兩次貨機載運鋰電池產生的事故，我以為美國早已經全面禁止客機托運了 @_@ (因為台灣與日本早就禁止了？)
Lithium-ion batteries can still be shipped on cargo aircraft. At least two deadly cargo jet crashes have been blamed on fires caused by these batteries. A Boeing 747 crashed in Dubai killing two crew members in 2010. In 2011, an Asiana Airlines 747 crashed off South Korea, also killing two crew members.
這邊提到的兩次貨機的空難分別是「UPS航空6號班機空難」(2010 年) 與「韓亞航空991號班機空難」(2011 年)，都是沒有人生還。
在「在 iOS 上不使用 Facebook App 時要完全砍掉 process」這邊提到了 Facebook 在 iOS 版的應用程式會在背景播放無聲音樂，導致吃電特別兇的問題，Facebook 的 Ari Grant 出來澄清是 bug 造成的，而非故意行為。
修正了兩個 bug，第一個是 network code 的部分：
The first issue we found was a “CPU spin” in our network code. A CPU spin is like a child in a car asking, “Are we there yet? Are we there yet? Are we there yet?”with the question not resulting in any progress to reaching the destination. This repeated processing causes our app to use more battery than intended. The version released today has some improvements that should start making this better.
第二個則是之前提到無聲 audio 的問題：
The second issue is with how we manage audio sessions. If you leave the Facebook app after watching a video, the audio session sometimes stays open as if the app was playing audio silently. This is similar to when you close a music app and want to keep listening to the music while you do other things, except in this case it was unintentional and nothing kept playing. The app isn't actually doing anything while awake in the background, but it does use more battery simply by being awake. Our fixes will solve this audio issue and remove background audio completely.
The issues we have found are not caused by the optional Location History feature in the Facebook app or anything related to location. If you haven't opted into this feature by setting Location Access to Always and enabling Location History inside the app, then we aren't accessing your device's location in the background. The issues described above don't change this at all.
在「The Background Data and Battery Usage of Facebook’s iOS App」這邊提到 Facebook App 在 iOS 上使用了非常吃電的技巧來強制背景更新。
作者猜測，如果你把 Facebook App 設定成不允許背景更新，那麼 Facebook App 會利用 iOS 在「播放音樂」可以在背景執行來進行更新：(所以只是打開播放的 channel，但是沒有聲音)
My guess is that Facebook is hijacking audio sessions on iOS by keeping silent audio in the background whenever a video plays in the app. And because, by default, videos on Facebook auto-play on both Wi-Fi and Cellular and few people ever bother to turn it off, that means there's a high chance the Facebook app will always find a way to play a video, keep audio in the background, and consume energy to perform background tasks.
I'm not alone in noticing the mysterious "Facebook audio" background consumption, and video auto-play seems to me the most likely explanation at this point. I don't know if turning off auto-play may fix the problem, but I'd recommend doing that anyway to save data.
印象中我們家的 zonble 也有提過類似的事情，當時他好像還有抱怨不知道 Facebook App 在搞什麼鬼... Anyway，這就可以理解作者提到為什麼這麼吃電：
On my girlfriend's iPhone, for instance, iOS 9 reports 5 hours of on-screen usage for the last 7 days, and another 11 hours of background audio usage with Background App Refresh turned off.
我的想法是，如果不用的時候就按兩下 home 鍵把 Facebook App 整個踢出去，或者就如同作者建議用 Safari 開行動版本：
I wonder if Apple should consider additional battery controls to take action against shady practices like invisible background audio. What Facebook is doing shows a deep lack of respect for iOS users. I continue to recommend using Safari instead.
出自「This killer trick will charge your iPhone 6 in half the time」，他們發現拿 iPad 的 12W 充電器充會快很多：
You can use a 12-watt iPad charger to juice up the iPhone 6 and iPhone 6 Plus in half the time when compared to the 5-watt iPhone charger your device ships with by default.