A portable power bank is a rechargeable battery that can charge a cellphone, tablet, or another small electronic device when an electrical outlet is unavailable.
It can be useful during travel, power outages, long appointments, outdoor activities, or roadside emergencies. A power bank can also provide peace of mind for anyone who depends on a cellphone for directions, communication, medical information, or emergency assistance.
Choosing one can be confusing because manufacturers advertise different capacities, charging speeds, connections, and features. The best power bank is not necessarily the largest or most expensive. It should provide enough power for your needs while remaining safe and convenient to carry.
Decide What You Need to Charge
Begin by identifying the devices you expect to charge.
These may include:
- Cellphone
- Tablet
- Wireless earbuds
- Smartwatch
- Rechargeable flashlight
- Camera
- Small laptop
A power bank suitable for a cellphone may not provide enough power for a laptop. Check the charging requirements for your device before making a purchase.
If you only need emergency phone power, a small model may be sufficient. If you travel frequently or need to charge several devices, a larger-capacity model may be more appropriate.
Understand Battery Capacity
Power-bank capacity is commonly listed in milliamp hours, abbreviated as mAh. A larger number generally indicates that the power bank stores more energy.
Common sizes include:
Approximately 5,000 mAh
This size is usually small and easy to carry. It may provide useful emergency power for a cellphone without adding much weight to a pocket or bag.
Approximately 10,000 mAh
This is a popular general-purpose size. It usually offers a reasonable balance between capacity, weight, and portability.
Approximately 20,000 mAh
A larger model may charge several devices or provide power over a longer trip. However, it will generally be heavier and take longer to recharge.
The advertised capacity does not equal the exact amount of power delivered to your device. Some energy is lost during voltage conversion, cable transmission, and charging. The number of complete charges will also depend on the battery size and condition of the device being charged.
Treat manufacturers’ charging estimates as approximations rather than guarantees.
Look at Charging Speed
Capacity tells you how much energy the power bank stores. Charging speed tells you how quickly it can deliver that energy.
Charging power is commonly measured in watts. Your phone, cable, and power bank must support compatible charging standards to receive the fastest available speed.
USB Power Delivery, often shown as USB PD, is a common fast-charging system used with USB-C connections. It allows compatible devices and chargers to communicate and select an appropriate power level.
A high-output power bank will not automatically force excessive power into a compatible device. However, the device, cable, and charger all need to support the appropriate standard.
Before purchasing, check:
- The charging wattage supported by your device
- The maximum output of the power bank
- Whether the correct port supports that output
- Whether an appropriate cable is included
- How quickly the power bank itself can be recharged
Understand the Connections
Power banks may include several types of connections.
USB-C
USB-C is becoming the most common connection for newer phones, tablets, laptops, and accessories. On some power banks, the same USB-C port can recharge the power bank and charge another device.
USB-A
USB-A is the familiar rectangular connection found on many older chargers and cables. It remains useful for equipment that does not use USB-C.
Built-In Cables
Some power banks have an attached charging cable. This is convenient because there is one less item to carry. However, a damaged built-in cable may be difficult or impossible to replace.
Choose connections that match the devices and cables you already own. Carrying a power bank without the correct cable will not help in an emergency.
Consider Size and Weight
A large power bank provides more stored energy but may be too heavy for everyday carry.
Think about where it will be kept:
- Purse
- Backpack
- Briefcase
- Vehicle emergency kit
- Travel bag
If you intend to carry it every day, size and weight are important. A power bank left at home because it is too heavy provides no benefit.
A smaller model may be better for daily use, while a larger one can be reserved for trips, power outages, or emergencies.
Decide How Many Ports You Need
A power bank with multiple output ports can charge more than one device. This may be useful for families, travel partners, or someone carrying both a phone and another electronic device.
However, total charging power may be divided between the ports when multiple devices are connected. Each device may charge more slowly than it would alone.
Read the product specifications to learn:
- How many devices can be charged at once
- Which port provides the fastest charging
- Whether total output decreases with multiple devices
- Whether USB-C can be used for both input and output
Do not pay for additional connections that you are unlikely to use.
Battery-Level Indicators
A power bank should provide a way to determine how much power remains.
Basic models may use four small lights, with each light representing approximately one-quarter of the battery. Other models have a numerical display showing the estimated remaining percentage.
A numerical display may be easier to understand, but no indicator will be perfectly precise. Recharge the power bank regularly rather than waiting until it is completely empty.
Wireless and Magnetic Charging
Some power banks can charge compatible phones wirelessly or attach magnetically to the back of the device.
These features eliminate the need to hold the phone and power bank together with a cable. However, wireless charging may be slower, generate more heat, and lose more energy than wired charging.
If convenience is your priority, wireless charging may be worthwhile. If efficiency and maximum battery life are more important, a cable is generally the better choice.
Confirm that your phone and case are compatible before purchasing a magnetic or wireless model.
Choose a Dependable Product
A power bank contains a lithium-ion battery. Poor manufacturing, physical damage, incompatible charging equipment, or extreme temperatures can increase the risk of overheating or fire.
Look for:
- An established manufacturer
- Clear model and capacity information
- Printed safety instructions
- Warranty and customer support
- Overcharge and short-circuit protection
- Independent safety testing or certification
- Clearly marked electrical ratings
- Positive reviews from several trustworthy sources
Be cautious of products with no recognizable manufacturer, missing safety information, exaggerated capacity claims, or prices that seem unrealistically low.
Before buying or using a power bank, search the Consumer Product Safety Commission recall database for the brand and model.
Use and Store It Safely
Follow the manufacturer’s instructions and use the recommended charging equipment.
Basic precautions include:
- Do not use a swollen, cracked, punctured, leaking, or unusually hot power bank.
- Do not leave it charging unattended for long periods.
- Do not charge it under a pillow, blanket, or other material that traps heat.
- Keep it away from water and direct sunlight.
- Do not leave it in a hot vehicle.
- Protect it from crushing, dropping, and sharp objects.
- Keep metal objects away from exposed connections.
- Stop using it if you notice smoke, odor, unusual sounds, swelling, or excessive heat.
A damaged or recalled lithium-ion power bank should not be placed in household trash or ordinary curbside recycling. Follow the manufacturer’s recall instructions or contact a local household hazardous-waste program for guidance.
Traveling by Air
Power banks contain lithium-ion batteries and are treated as spare batteries during airline travel.
Under current Federal Aviation Administration rules:
- Power banks must be carried in the passenger cabin.
- They are not permitted in checked luggage.
- Most power banks rated at 100 watt-hours or less are allowed.
- With airline approval, passengers may carry up to two power banks rated over 100 watt-hours and no more than 160 watt-hours.
- Power banks rated above 160 watt-hours are not permitted on passenger aircraft.
- Damaged or recalled power banks should not be taken aboard an aircraft.
Check the watt-hour rating printed on the power bank and review your airline’s rules before traveling. Airline and international restrictions may be more limiting than the general federal requirements.
Maintain the Power Bank
A power bank should be checked regularly, especially if it is stored for emergencies.
Once a month:
- Check the remaining charge.
- Recharge it if necessary.
- Inspect it for swelling or damage.
- Examine cables and connections.
- Confirm that it can charge your phone.
- Review the model for safety recalls.
Batteries gradually lose capacity with age. Replace a power bank that no longer holds a dependable charge or shows signs of deterioration.
Portable Power Bank Buying Checklist
Before choosing a model, ask:
- Which devices do I need to charge?
- How much capacity do I realistically need?
- Is the power bank comfortable to carry?
- Does it have the correct connections?
- Does it support my device’s charging speed?
- Is the correct cable included?
- How long does the power bank take to recharge?
- Can I understand its battery indicator?
- Does the manufacturer provide safety information and support?
- Has the model been recalled?
- Is its watt-hour rating clearly marked for airline travel?
- Am I paying for features I will not use?
Final Thoughts
A portable power bank can be an excellent addition to an everyday carry kit, but capacity is only one consideration. Charging compatibility, size, weight, safety, connections, and product support are equally important.
Choose a model that matches the devices you use and the way you plan to carry it. Keep it charged, inspect it regularly, and replace it if it becomes damaged or unreliable.
A dependable power bank can help keep your cellphone available when communication matters most.
Gear Up Daily helps you carry smart and stay prepared.
