That app is essential because there's a Find My feature built into the battery. It doesn't work like an AirTag over UWB, it's only Bluetooth, but it's useful if you misplace your battery in your office (or you have multiple batteries, like I do).

You don't have a magnetic phone: You don't need an iPhone to enjoy the magnetic charging, but you'll need a case that lines up your phone with Apple's MagSafe wireless configuration, or else your phone won't charge properly. When evaluating the performance of a 4000mAh power bank, it’s important to consider real-world usage scenarios and factors that can impact its longevity. While the mAh rating gives us an idea of the power bank’s capacity, the actual performance can vary based on several factors.

Don’t get stuck without a charger for your gadgets. We’ve picked out the best power banks to help you recharge while you’re on the go

Additionally, it’s worth mentioning that using a power bank’s full capacity in one go can lead to a shorter lifespan and reduced overall performance of the power bank over time. It’s advisable to use the power bank intelligently, considering how much charge you actually need and recharging the power bank before it completely drains to prolong its lifespan.

Smartphones: Most smartphones today have battery capacities ranging from 2000mAh to 4000mAh. Charging a smartphone with a 2000mAh battery from a 4000mAh power bank can take approximately 1-2 hours, considering the conversion losses and power bank efficiency. However, smartphones with larger battery capacities may take longer to charge fully, typically around 2-4 hours. The Anker Prime series of Power Banks, including the Anker Prime 27,650mAh Power Bank (250W) and the Anker Prime 20,000mAh Power Bank (200W), are for people who truly love to geek out on power banks. If you came looking for the absolute best power bank you can buy, this is the best we've tried.In the next section, we will provide some tips to optimize the usage of a 4000mAh power bank and enhance its longevity. Recharge the Power Bank Regularly: Keeping your power bank charged is essential for its longevity. Recharge it as soon as possible after use, rather than letting it fully drain, to prevent wear on the battery cells. Conversion losses occur due to factors such as internal resistance, heat dissipation, and voltage conversion. These losses can vary between power bank models and brands, and they can impact the actual charging capacity and the number of charges a power bank can provide.

Avoid Overcharging: Do not leave your power bank plugged in for an extended period after it’s fully charged. Overcharging can degrade the battery’s performance and lifespan over time. To test charging times and claims, we charged a Samsung Galaxy S23 Ultra and an Apple iPhone 15 to determine how many charges each battery offers these devices. We chose a common smaller battery phone as well as our best phone overall for this purpose. It’s important to note that these estimates are rough guidelines and can vary depending on the specific power bank model and the device being charged. Some power banks may have better energy efficiency, resulting in higher charging capacities, while others may have lower efficiency, reducing the overall charging capacity. In the next section, we will estimate the charging capacity of a 4000mAh power bank and explore the typical charging times for different devices. If the power bank you buy doesn’t include a case, buy one. Power bank cases are great for carrying USB cables and keeping your charging ports clean and free from dust. Power bank capacities

Tips

For example, a power bank with a rating of 4000mAh can theoretically provide a current of 4000 milliamperes for one hour, or 2000 mA for two hours, before its charge is fully depleted. However, it’s important to remember that this is an ideal scenario and not necessarily reflective of real-world usage. It’s important to manage your expectations and consider the specific requirements of your devices when using a 4000mAh power bank. If you have devices with larger battery capacities or if you require multiple full charges, you may need to opt for a higher-capacity power bank to meet your needs.

We expect this competition will heat up next year as more power bank makers catch up and make faster charging batteries. Until then, Anker is the dominant brand, and if you want the best it's an easy choice. How many times can my power bank charge my phone? When it comes to power banks, the relationship between the charging capacity and the battery size of the devices being charged is crucial to understanding the capabilities of a 4000mAh power bank. Let’s explore how the battery size of a device affects the charging capacity provided by a 4000mAh power bank. These portable power banks are popular among phone users for a good reason—they offer enough capacity. They are also quite lightweight and easy to carry.Charge the Power Bank Fully: Before using your power bank for the first time, make sure to charge it fully. This maximizes its charging capacity and ensures optimal performance.