Apple Watches have been rumored to drain iPhone batteries. Some people say it does, while others say it doesn’t. For the truth, we conducted some research.
Our findings will be discussed in this blog post, and we will tell you if the Apple Watch drains the iPhone’s battery.
Does Apple Watch Drain iPhone Battery?
I would say yes, especially if you use your watch a lot. Your iPhone’s battery will drain faster if you use your Apple Watch a lot. On the other hand, if you use it sparingly, your iPhone’s battery life will be significantly extended.
Apple Watch and iPhone communicate through Wi-Fi, Bluetooth, connected apps, and GPS. Data exchange on your iPhone involves a lot of power, which can quickly drain its battery.
There are reports on multiple forums that the iPhone battery drains less from the Apple Watch after a few months.
It may be due to the watch receiving some predictable data, which it won’t need to constantly check on the iPhone. Maps and GPS data can be stored during workout activities so that the watch won’t need to keep pulling data.
How Long Should an iPhone Battery Last?
It is tasted that iPhone battery last 10 -18 hours, depending on how much you use them. Sparingly using your phone will prolong its battery life compared to heavily using it.
Techradar tested the iPhone XR (2942 mAh) rigorously with a full charge for a day. It lasted about 17 hours due to its energy-efficient algorithm.
Additionally, they performed a similar test on the iPhone XS Max ( 2,716 mAh) with impressive results of 15 hours.
The older iPhone models perform worse because Apple is constantly improving the energy efficiency of the newer models.
Depending on factors such as your usage, phone settings, iPhone model, battery condition, and others, you may not get a similar result as described above.
Why Does My iPhone Battery Draining Fast When Paired With the Apple Watch?
Here are some reasons why your Apple Watch drains your iPhone battery;
- Bluetooth and remote control: The Apple Watch and iPhone communicate via Bluetooth, which does not consume much power, but active data exchange via Bluetooth can drain the iPhone battery. The Apple Watch can also be used to adjust some iPhone settings like camera function. Which could really drain the battery on your iPhone.
- Mapping your workout data: It is normal to notice a significant battery drain during the first few months after pairing your Apple Watch with your iPhone. It takes a lot of energy to construct your trail during the first two or three months. Satellite images are used to map your daily routine. After this, the iPhone’s battery consumption should stabilize as the processor isn’t working as hard on these tasks.
- Third-party apps: Some third-party workout apps like Runkeeper and Strava run in the background and require cellular data to function effectively. They constantly monitor your progress and update your metrics on the iPhone. As a result, you may notice a significant battery drain on your iPhone when exercising.
- Sending and Receiving data via cellular connections: You can also drain your iPhone battery when you send and receive messages or make calls using WiFi and cellular networks. Especially in an area with poor cellular signals. It takes an iPhone’s battery a lot longer to send and receive messages or stream data when the device constantly switches between WiFi and cellular.
- Software update: Upon installing iOS 14 and Watch OS 7, users found iPhone 8’s battery drain was enormous. Using Apple Watch with iPhone significantly increases the drain. To rectify the issue, Apple provided some guidelines. Next, I’ll explain how to resolve the software update issue.

How to Make Your iPhone Battery Last Longer? 13 Tips
Many of you asked how to keep iPhone battery health at 100% to maximize its performance. The battery on your iPhone can be extended in a few ways. They are:
1. Turn off location services
The battery on your iPhone will last longer if the GPS and other location services are not used.
2. Reduce screen brightness
You can also conserve energy on your iPhone by reducing screen brightness.
3. Activate Low Power Mode
In Low Power Mode, your phone only performs the most essential tasks, so background activities such as mail fetching and downloading are disabled.
You can activate Low Power Mode manually to keep your phone going for longer. Go to Settings >> Battery >> Low Power Mode and toggle it on. The battery icon will turn yellow when activated.
4. Disable notifications for apps you rarely use
It will prevent your phone from constantly searching for new notifications.
5. Close unused apps
Close any unused apps you have open. It will save energy and free up some processing power.
6. Turn Off Background App Refresh
An iOS app will continue running for a little while after you close it. However, Background App Refresh allows suspended apps to check for updates and new content-a processes that can drain batteries.
Background App Refresh can be disabled completely or just for certain apps. Go to Settings >> General >> Background App Refresh
7. Switch to Airplane Mode
In an emergency, set your phone to Airplane Mode, which turns off all wireless features. There will be no calls or texts, but you can use Wi-Fi for iMessages and other tasks if necessary.
8. Set Auto-Lock to 30 Seconds
When not in use, your iPhone will automatically go into standby mode, thereby saving battery life. Go to Settings >> Display & Brightness >> Auto-Lock and choose 30 seconds as the minimum interval.
9. Turn Off Wi-Fi, Bluetooth, and AirDrop
When you don’t use Wi-Fi, you’ll waste less data, but it won’t benefit your battery. When you’re out, your phone searches for Wi-Fi networks nearby.
Similarly, Bluetooth and AirDrop are constantly looking to connect, but they don’t need to be always active. It is quickest to shut off these services through the Control Center.
- Go to Settings >> Wi-Fi,
- Settings >> Bluetooth, and
- Settings >> General >> AirDrop >> Receiving Off to turn them off.
10. Update to the latest iOS version
Apple regularly updates its iOS software with battery-saving optimizations. For the best battery life, make sure you’re running the latest iOS version.
11. Remove casings before charging
Some cases cause the iPhone to heat up when charging. Be sure to remove the phone’s casing before charging it.
12. Avoid extreme temperatures
Apple devices should be kept between 16°C and 22°C. This is the zone where it feels most comfortable. Temperatures above 35°C can damage your gadget’s battery, as well as reduce its lifespan.
13. Charge iPhone 50% when storing for a long time
When fully charged batteries are stored, they can become deeply discharged, making it difficult to recharge them in the future. If you charge it to 50%, it will slowly discharge when not in use.
How to Save Battery Life on Apple Watch
Apple Watches can conserve energy just like iPhones. They are:
- Turn off cellular data
- Reduce screen brightness
- Disable notifications for apps that you use rarely
- Close unused apps
- Update to the latest watchOS version
- Disconnect the Bluetooth and Wi-fi
Will Apple Watch Work if Phone is Dead or Powered Off?
The answer is yes, but not fully. Some Watch features (for GPS-only models) require data connectivity with the iPhone to function. These features will not work if the iPhone’s battery dies.
However, many other Watch features, including basic timekeeping, fitness tracking, and heart rate monitoring, will still function without the iPhone connection.
The Apple Watch with GPS + Cellular does not require a connected iPhone to use cellular data. The Watch’s cellular and data functions will still be functional if your iPhone’s battery dies.
How to Charge Apple Watch and iPhone After Their Battery Drains
There are a few ways to charge your Apple Watch and iPhone. Below are the most common methods:
1. Charging Cable: Connect the charging cable to a USB port and let it charge. Charge the Apple Watch with iPhone this way.
2. Wall Charger: You can charge your devices using a wall socket charger. Plug the device into the wall socket and let it work.
3. Power Bank: Using a power bank can give your devices some extra juice when they run out of battery.
4. Wireless Charging: iPhone 8 and later models have wireless charging capabilities thanks to Qi-certified chargers. The Wireless Power Consortium (WPC) established the Qi charging standard, which is an open, worldwide standard for wireless charging.
With Apple’s wireless magnetic charging docks, Apple watches can also be charged wirelessly. Using this method, you can charge your device without a cable.
Using a compatible wireless charger is all you need to do. You can also charge the apple watch with a lightning cable.

Conclusion
Over time, batteries will lose their ability to hold charge since they are consumables. Therefore, the Apple Watch definitely affects the iPhone battery in some way.
However, it depends on your use and which settings are enabled. It is possible to extend the battery life of both devices by following some simple tips mentioned in this article.
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