The Best External Power Supply for Smartphones

Your smartphone is your daily companion, but its battery doesn’t always keep up.

Whether you’re traveling, working remotely, or just spending a long day out, a reliable external power supply for smartphones ensures you stay connected without hunting for an outlet.

The market is flooded with options, from slim battery packs to high-capacity behemoths with AC outlets, making it tough to choose the right one.

At BestProducts, we research and analyze specifications, expert review consensus, and verified buyer feedback to score each model on our 0-to-10 BP Score, so you can find the portable power solution that fits your lifestyle.

Below, you’ll find our top picks based on thorough evaluation.

Best External Power Supply for Smartphones Buying Guide

Capacity and Portability

The most important trade-off in any external power supply for smartphones is between capacity (measured in milliampere-hours, or mAh) and physical size.

A 10,000mAh pack can fully recharge most phones two to three times and fits easily in a pocket, while a 50,000mAh unit may weigh over a pound but can keep multiple devices running for days.

Consider your typical usage: daily commuters often prefer slim, lightweight models that slip into a bag, while travelers or campers benefit from high-capacity bricks that also power tablets, headphones, or even a laptop.

For reference, a 20,000mAh bank strikes a popular balance, enough for several phone charges without being too bulky.

Look for the energy rating in watt-hours (Wh) as well, especially if you fly. Most airlines allow power banks up to 100Wh in carry-on luggage, but larger ones may require approval.

A good rule: 20,000mAh at 3.7V equals about 74Wh, well within limits. If you need more, check our guide on 120 volt power supplies for boondocking for high-capacity options designed for extended off-grid use.

Charging Speed and Power Delivery

Not all charging speeds are created equal. Modern smartphones support fast charging standards like USB Power Delivery (PD) and Qualcomm Quick Charge (QC).

A good external power supply for smartphones should output at least 18W via USB-C PD to charge an iPhone or Samsung Galaxy quickly; 22.5W or 30W is even better for topping up in under an hour.

Some models also include a built-in AC outlet, which can deliver up to 65W, enough to run a laptop or charge a camera battery simultaneously.

Keep in mind that charging speed also depends on the cable and the phone’s own limits. Look for power banks with multiple output ports so you can charge two devices at once without dropping speed.

If you need a dedicated high-wattage solution for your laptop, our roundup of multi-outlet power supplies for keyboards covers desktop alternatives.

Number and Type of Ports

Port configuration can make or break your charging experience. Most modern external power supplies include at least one USB-C input/output and one or two USB-A ports.

Some models now feature built-in cables (Lightning, USB-C, Micro-USB), which are incredibly convenient, you never have to carry extra cords. For group travel or family use, a power bank with three or four outputs allows everyone to charge at once.

Check whether the USB-C port supports bidirectional charging (input and output) to simplify cable management. If you often charge both an iPhone and an Android device, look for a model with both Lightning and USB-C built-in cables.

For more advice on choosing the right accessories, see our picks for noise cancelling headphones for smartphones, another essential travel companion.

Additional Features: AC Outlets, Displays, and Safety

Some external power supplies for smartphones go beyond simple battery packs. Models with a built-in AC outlet let you plug in small appliances, a laptop charger, or even a fan, perfect for camping or power outages.

A digital LED display shows remaining capacity in percentage, so you’re never caught off guard. Pass-through charging (charging the power bank while it charges your phone) is another handy feature for overnight use.

Safety certifications matter too: look for overcharge, over-discharge, and short-circuit protection. Reputable brands ensure compliance with UL, CE, or FCC standards.

For a deeper dive into power supply safety, check out our guide to 300W power supplies for compact builds, which covers similar protection features in a desktop context.

Why You Should Trust Us

BestProducts is an independent review site dedicated to helping you make informed purchasing decisions. We do not conduct our own product trials; our evaluations are grounded in research, published data, expert review consensus, and verified buyer feedback.

Each product is scored on a 0, 10 BP Score using a consistent set of criteria tailored to its category, including capacity, charging speed, portability, build quality, and value. We update our recommendations regularly to reflect new models and price changes.

Our affiliate relationships do not influence our picks or scores; we prioritize transparency and accuracy above all.

Final Thoughts

• Best Overall: YILANS Portable Charger 50000mAh, With a BP Score of 9.9/10, this model leads the pack thanks to its massive 50,000mAh capacity, 22.5W fast charging, and four built-in cables (Lightning, USB-C, Micro-USB). It’s the ultimate travel companion for families or heavy users who need to charge multiple devices without extra cords.
• Best Slim Design: CFIAI Portable Charger 15000mAh, Scoring 9.8/10, this slim 15,000mAh power bank fits easily in a pocket yet includes built-in cables and 22.5W output. Perfect for daily commutes and light use.
• Best Budget Pick: Evopow 2 Pack Portable Charger 10000mAh, At 9.7/10, this two-pack offers exceptional value for under $20. Each 10,000mAh unit is compact and reliable for topping off phones on the go.
• Best for Laptops: ZeroKor Portable Power Bank with AC Outlet 65W, Another 9.7/10 scorer, this power bank includes a 110V AC outlet, making it ideal for charging laptops, cameras, and other small electronics during travel or power outages.

Frequently Asked Questions

What capacity external power supply do I need for my smartphone?

Most modern smartphones have batteries between 3,000 and 5,000mAh. A 10,000mAh power bank can charge your phone two to three times; 20,000mAh covers four to six charges.

For heavy use or multi-day trips without access to outlets, 30,000mAh or higher is recommended. Remember that larger capacities mean more weight, consider your portability needs.

Can I bring a power bank on a plane?

Yes, but with restrictions. Power banks must be carried in your carry-on luggage (not checked). Most airlines allow up to 100Wh (about 27,000mAh at 3.7V) without special approval. Between 100Wh and 160Wh you may need airline permission. Always check your airline’s policy before traveling.

What is pass-through charging and is it safe?

Pass-through charging lets you charge the power bank while it simultaneously charges your phone. It’s convenient for overnight use, but not all models support it safely. Look for power banks that explicitly advertise pass-through with temperature and current protection. Avoid cheap units that may overheat.

How do I know if a power bank supports fast charging for my phone?

Check the power bank’s output specifications. For iPhone 8 and later, USB Power Delivery (PD) at 18W or higher is needed for fast charging. Samsung Galaxy devices support both PD and Qualcomm Quick Charge (QC) 2.0/3.0.

Many power banks list compatible standards on the product page. If in doubt, look for a model that explicitly states “PD 20W” or “QC 3.0.”

Are power banks with built-in cables worth it?

Yes, if you value convenience and often forget cables. Built-in cables reduce clutter and are always attached. However, they can be shorter than standard cables and may not support the fastest charging speeds.

For most users, a power bank with both built-in cables and a separate USB-C port offers the best flexibility.

How long does it take to recharge a power bank itself?

Recharge time depends on the power bank’s capacity and input speed. A 10,000mAh power bank with 18W input can fully charge in about 3, 4 hours. A 50,000mAh unit may take 6, 8 hours with a 30W charger.

Some models support 65W input via USB-C, cutting the time significantly. Use the included cable and a high-wattage wall charger for fastest results.

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