External batteries have become increasingly popular, with many now equipped with USB-C connectors and fast charging capabilities, while others offer Qi wireless charging. Some models from smartphone buying guides may require additional charging at the end of the day, prompting the selection of the best external batteries. To maximize performance, a USB Power Delivery charger capable of quick charging is recommended. The Anker MagGo Power Bank 10000 mAh is highlighted as the best MagSafe external battery for recent iPhones and Google Pixel devices. It features Qi 2 certification, allowing up to 15W of wireless charging with minimal heating. The integrated magnets allow it to stay in place during use, and it can deliver up to 30W when used with a wired connection. It has a capacity of 10,000 mAh, which can charge an iPhone 15 Pro up to 1.8 times, according to Anker. Its dimensions are 10.4 cm by 7 cm and 1.5 cm in thickness, making it easy to carry. The Belkin MagSafe battery is an alternative for iPhone users. It offers Qi wireless charging at 7.5W and can charge other devices not bearing the Apple logo. It requires a USB-C socket for charging. While it is more expensive and has a limited capacity, it integrates well with iPhones and can serve as a Qi charger when plugged in. The UGreen Nexode Power Bank 20000 mAh is noted as a top choice for travel. It has a capacity of 20,000 mAh and can deliver up to 130W of power. It includes two USB-C ports (100W and 30W) and a USB-A port. It can charge a smartphone up to four times or a Nintendo Switch three times. The battery has a TFT screen to display output power and real-time voltage. However, during testing, it had issues with some devices, such as the Realme GT Master Edition, and the supplied cable was unreliable. The Anker PowerCore 5000 is recommended as a compact and affordable option for quick charging. It is cylindrical, weighs 136 grams, and has a 5,000 mAh capacity. It features a micro-USB input and a USB-A output of 10W (5V/2A). It does not support fast charging but is suitable for basic needs at a low price. The Anker Nano 10K offers a good balance of size and capacity. It is compact, measuring 8 cm in height and weighing 230 grams. It includes a retractable 70 cm USB-C cable and can charge multiple devices simultaneously via a second USB-C port and a USB-A port. It delivers up to 45W on a single USB-C port but 22.5W in total when multiple devices are connected. It can charge a Pixel 8a at 18W, providing about 1% of battery per minute, and a MacBook Air with up to 43W. It includes a built-in screen to monitor temperature and has a reasonable price of 50 euros. The Lisen 5000 mAh external battery is a compact wireless option. It targets iPhones compatible with MagSafe, offering 15W of charging power and adhering to the phone's back. It can also charge devices without integrated magnets, such as the Samsung Galaxy S24 FE, though efficiency may be reduced with cases. It includes a LED indicator to show battery levels and charging status. The Anker PowerBank 25K 165W is a large battery designed for travel, with a capacity of 25,000 mAh and a charging power of 165W. It includes two USB-C cables, one of which folds into a carrying strap. It can charge multiple devices simultaneously, including PCs or portable consoles. It has a reinforced side with a USB-C and USB-A port. It can deliver up to 100W on one port and 65W on another simultaneously, with a total power of 130W when multiple devices are connected. It is recommended for users needing power for multiple devices on the go. The mophie Powerstation Plus 5000 mAh is ideal for emergency situations. It has a 5,000 mAh capacity and includes a USB-C and Lightning cable. It also has a USB-C port for charging and reversing the power flow to the phone. It has a starting price of 50 euros, which is higher than some competitors, and its charging power is limited to 20W. Choosing an external battery involves considering several factors, including capacity (measured in mAh), charging power (in watts), compatibility with MagSafe or Qi2, weight and size, and brand reliability. The capacity of a battery does not directly translate to the number of recharges a smartphone can receive due to differences in voltage and efficiency. A formula is provided to calculate the number of recharges based on the external battery's capacity, smartphone battery voltage, and efficiency. For travel, a 10,000 mAh battery is commonly requested, while a 20,000 mAh battery can charge multiple devices. A 50,000 mAh battery is suitable for charging multiple devices or PCs. Trusted brands include Anker, RavPower, and Aukey, and the presence of the CE standard is recommended for safety. Precautions for using portable batteries include avoiding exposure to heat and ensuring proper ventilation. The choice of battery depends on the intended use, with smaller batteries being more convenient for daily use and larger ones suitable for charging laptops or multiple devices.