[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["缺少我需要的資訊","missingTheInformationINeed","thumb-down"],["過於複雜/步驟過多","tooComplicatedTooManySteps","thumb-down"],["過時","outOfDate","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["示例/程式碼問題","samplesCodeIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間:2025-07-27 (世界標準時間)。"],[],[],null,["# Excessive battery usage\n\n| **Note:** Excessive battery usage is only available for watch face apps with sufficient usage data.\n\nExcessive battery usage is the percentage of watch face sessions where battery\nusage exceeds 4.44% per hour. Google Play collects this data when devices aren't\ncharging and no apps are in use.\n\nWhen battery usage exceeds 4.44% per hour the watch won't last a full day on a\nsingle charge. This harms users and the Wear OS ecosystem.\n\nTo maximize battery life, aim for battery usage under 3.2% per hour.\n\nEfficiency requirements\n-----------------------\n\nAn efficient watch face app should have:\n\n- \\\u003c 1% excessive battery usage\n- \\\u003c 3.2% battery usage per hour for 80% of sessions\n\n| **Warning:** If excessive battery usage exceeds 1%, Play may reduce your app's visibility. See [core vitals FAQ](/topic/performance/vitals#core-vitals-faqs) for more details.\n\n[Vitals](/topic/performance/vitals) provides the following data:\n\n- Excessive battery usage over time\n- Battery usage per hour histogram\n- Contributing factors\n- Breakdowns\n\nContributing factors\n--------------------\n\nThese are key factors affecting your app's battery usage:\n\n- **Excessive CPU usage:** The portion of watch face sessions that use the CPU for 90 seconds or more per hour.\n- **Excessive partial wakelocks:** The portion of watch face sessions use wakelocks for 18.5 seconds or more per hour.\n\nUse [breakdowns](#breakdowns) and [Battery Historian](/topic/performance/power/battery-historian) to investigate further.\n\nBreakdowns\n----------\n\nBreakdowns group affected sessions by characteristics such as OS, device, and\nregion. Select a breakdown to see an hourly battery usage histogram for that\ngroup.\n\nReduce battery usage\n--------------------\n\nUse the following suggestions to reduce your app's battery usage.\n\n### Use Watch Face Format\n\n[Watch Face Format](/training/wearables/wff) uses declarative XML instead of executable code to\nsimplify app creation and reduces battery usage.\n\n### Handle Always on display (AoD) mode\n\nWhen a watch isn't in use it switches to Always-on display (AoD), also called\nambient mode. In AoD, your watch face should [illuminate no more than 15% of\npixels](/docs/quality-guidelines/wear-app-quality#always-on-display).\n\n### Optimize memory usage\n\nLarge images, fonts, and animations (like sweeping second hands) increase\nbattery usage.\n\n- Use the lowest resolution resources needed\n- Crop resources to their minimum size (avoid transparent borders)\n- Remove or crop anything hidden by other elements to reduce overdraw\n\n| **Tip:** Use the [Watch Face Format Optimizer](https://github.com/google/watchface/tree/main/tools/wff-optimizer) to automatically apply some optimizations.\n\nSee [Optimize memory usage](/training/wearables/wff/memory-usage) for more suggestions.\n\n### Limit animations\n\nAnimating elements makes watch faces visually appealing but uses more battery.\nTo reduce their impact:\n\n- Avoid using high fps animations\n - For most animations 15 fps is recommended\n- Limit usage of dynamic elements such as [Gyro](/training/wearables/wff/common/transform/gyro) and [ArithmeticExpression](/training/wearables/wff/common/attributes/arithmetic-expression)\n - `ArithmeticExpression` updates as frequently as its source data. High frequency sources such as `MILLISECOND` and `ACCELEROMETER` use more battery.\n- Avoid unnecessary animations in AoD mode\n\n### Avoid wakelocks\n\nPublish your app using [Watch Face Format](/training/wearables/wff) to avoid wakelocks.\n\nRecommended for you\n-------------------\n\n- Note: link text is displayed when JavaScript is off\n- [Watch Face Format](/training/wearables/wff)\n- [Power considerations](/design/ui/wear/guides/surfaces/watch-faces#power_considerations)\n- [Battery Historian](/topic/performance/power/battery-historian)"]]