Anker Nano A1638 vs INIU P55-E2: Which 10,000mAh Power Bank Is Better?

Anker Nano A1638 vs INIU P55-E2 is a close comparison between two 10,000mAh power banks that advertise up to 45W USB-C output. The better choice is not determined by wattage alone: the Anker has a longer retractable cable, a more informative display and stronger multi-device output, while the INIU is thinner, lighter and usually positioned as the value option.

For most buyers, the Anker Nano A1638 is the better convenience-first choice because its 2.3-foot retractable cable is more useful during everyday charging and its combined output is less restricted. The INIU P55-E2 is the better portability-and-value choice if it is available at a meaningfully lower price and you prefer a flatter body, detachable lanyard cable, phone stand and three-year warranty.

This is a research-based comparison using manufacturer specifications and exact model information, not a hands-on laboratory test. Charging speed, usable capacity, temperature and runtime vary by device and conditions. Prices and stock also change, so verify the exact model and seller before ordering.

Affiliate disclosure: TopProdReviews may earn a commission from qualifying purchases made through Amazon links, at no additional cost to you. Affiliate relationships do not determine our recommendations.

Quick verdict

Choose the Anker Nano A1638 if you want the most convenient built-in cable, a compact footprint, clearer charging information and better output when two or three devices are connected. It is especially appealing for people who charge while using a phone because the retractable cable extends to approximately 2.3 feet.

Choose the INIU P55-E2 if you want a slimmer, lighter power bank with a detachable USB-C lanyard cable, listed PPS support, a phone holder, an emergency flashlight and three-year INIU Care. Its strongest advantage is value, but its 15W total output during multi-device charging is an important limitation.

• View the exact Anker Nano A1638 listing on Amazon.com
• View the exact INIU P55-E2 listing on Amazon.com

Anker Nano A1638 vs INIU P55-E2 at a glance

The specifications above are manufacturer claims rather than TopProdReviews measurements. The INIU is longer and wider but about half as thick and roughly 1.7 ounces lighter. The Anker occupies less surface area but is noticeably thicker.

Charging speed: both reach 45W, but compatibility decides the result

Both models advertise a maximum single-device USB-C output of 45W. The Anker lists that maximum from either its retractable cable or separate USB-C port. INIU lists PPS, USB Power Delivery, Quick Charge, AFC and FCP support, while Anker’s guidance confirms PPS compatibility for supported Samsung and Google devices.

A 45W label does not mean every product will draw 45W. A compatible Samsung phone may use the higher PPS ceiling, while many iPhones and Pixel phones will negotiate less. Battery percentage, temperature and the device’s own limit also affect speed. Some low-power laptops may accept 45W, but 10,000mAh provides limited reserve; a 20,000mAh or larger model is usually more practical for laptop use.

Charging-speed winner: Tie for one compatible device. Both offer the same advertised 45W maximum, and real performance depends more on protocol and device compatibility than the brand name.

Cable design: retractable reach versus a detachable lanyard

Cable design is the biggest practical difference in the Anker Nano A1638 vs INIU P55-E2 decision.

The Anker has a built-in retractable USB-C cable that extends to approximately 2.3 feet. You can place the bank in a bag or on a table and use the connected phone without holding both products together. The cable retracts for storage. Anker says its InstaCord was tested for repeated bends and pulls, although that is a manufacturer claim rather than independent TopProdReviews testing.

The INIU uses a 0.4-foot braided USB-C cable that doubles as a lanyard. INIU identifies it as detachable, making replacement easier than with a permanently integrated cable. However, its short reach is less comfortable when the bank rests separately on a desk or inside a bag.

The INIU product page may show more than one cable-style option, so check that the selected Amazon listing is the exact P55-E2 configuration described here. A similar product photo or a shared 45W rating does not guarantee that the model, cable or features are identical.

Cable winner: Anker Nano A1638. INIU’s lanyard is compact and replaceable, but the Anker’s longer retractable cable is more versatile for everyday use.

Size and weight: INIU is easier to slip into a pocket

The INIU P55-E2 measures 4.4 by 2.7 by 0.7 inches and weighs 6.5 ounces. Its flat shape resembles a small phone more than a compact block, so it should fit more naturally in a jacket pocket, laptop sleeve or narrow organizer compartment.

The Anker A1638 measures 3.21 by 1.99 by 1.42 inches and weighs about 8.2 ounces. It is shorter and narrower than the INIU but more than twice as thick, producing a larger pocket bulge.

The Anker saves length and width on a crowded desk, while the INIU’s flatter shape fits more naturally beside a phone. A narrow accessory pouch may favor Anker; a pocket or laptop sleeve will usually favor INIU.

Portability winner: INIU P55-E2. It is thinner and lighter, which matters more than a shorter body for many commuters.

Multi-device charging: the Anker has more total power

Single-device ratings can hide a large difference in shared output. Anker lists 22.5W total when its cable and USB-C port work together: up to 15W for the cable and 7.5W for the port. With all three outputs active, Anker lists 7.5W for each.

INIU lists 15W total whenever two of the P55-E2’s outputs are used together and 15W total across all three outputs. That is enough for slow charging or maintaining several small devices, but it removes the main benefit of the 45W rating. If you connect a phone and tablet simultaneously, neither receives the model’s maximum single-port output.

For the fastest result, connect one priority device. If you regularly share with a second phone or charge earbuds alongside a handset, Anker’s extra 7.5W of total shared output makes it more capable, although both slow down with multiple connections.

Multi-device winner: Anker Nano A1638. Its 22.5W combined ceiling is still modest, but it is better than the INIU’s 15W shared limit.

Displays and extra features

Anker equips the A1638 with a light-sensitive screen that shows battery and charging information more clearly than basic indicator lights. It also includes a trickle-charging mode for small accessories such as earbuds.

INIU emphasizes practical extras: a phone holder, emergency flashlight, carrying lanyard, TempGuard 2.0 temperature monitoring and three-year INIU Care. The stand can help when watching video while charging, while the light may be useful during travel or a power outage.

Anker promotes its ActiveShield 3.0 temperature-monitoring system and a retractable-cable durability test. Both companies’ safety and durability statements are manufacturer claims, not independent proof that one bank will outlast the other.

Feature winner: Depends on your priorities. Anker offers the more useful charging display; INIU offers more non-charging extras and a clearly stated three-year warranty.

Recharging the power bank

The Anker supports up to 30W USB-C input, while INIU lists up to 27W. That small advantage may help the A1638 refill faster under compatible conditions, but both require an appropriate USB-C Power Delivery wall charger.

Both use USB-C input. The Anker’s retractable cable supports two-way charging, so it can refill the bank without another cable. INIU’s lanyard cable also supports charging and recharging, but verify the selected configuration because INIU displays multiple cable options.

Input power falls as batteries fill or warm up. If recharging is unexpectedly slow, use a known-good USB-C Power Delivery adapter, connect only the bank and keep it cool. Our guide to why a power bank charges slowly explains the common causes.

Recharging winner: Anker Nano A1638 by a narrow margin. Its listed 30W input is slightly higher, and the retractable cable adds convenience.

Which is better for iPhone, Samsung and Google Pixel?

For a recent USB-C iPhone, either bank can negotiate the wattage the phone supports. Anker provides more cable reach, while INIU sits flatter beside the phone. Owners of iPhone 14 and earlier models need a compatible USB-C-to-Lightning connection.

For compatible Samsung Galaxy models, both list the 45W-class ceiling and PPS support. A standard Galaxy may accept less than an Ultra or Plus model, so check the exact phone specification.

For Google Pixel phones, both list USB Power Delivery and PPS compatibility, but the phone requests only what its model and battery conditions allow. For more choices, see our best power banks for Android phones and best power banks for iPhone guides.

Air travel and battery safety

Both models are below the common 100Wh threshold, but power banks are spare lithium batteries. The Federal Aviation Administration says they must travel in carry-on baggage, not checked baggage, with terminals protected against short circuits. Check airline and destination rules before traveling.

Inspect any power bank before use. Stop using it if the enclosure is swollen, cracked, leaking, unusually hot or damaged, or if it develops an odor or erratic behavior. Keep the ports away from loose metal objects, avoid charging under bedding or in direct sunlight and follow the manufacturer’s storage instructions.

For recall checks, search the manufacturer and U.S. Consumer Product Safety Commission databases using the complete model identifier. A notice for another Anker or INIU model does not automatically cover the A1638 or P55-E2.

Price, availability and long-term value

Retail prices, coupons, colors and third-party sellers can change daily, so this comparison does not rely on a fixed dollar amount. Instead, compare the checkout price of the exact A1638 and P55-E2 models from reputable sellers.

The INIU is the stronger value only when it costs meaningfully less and is actually available. During the editorial verification for this article, INIU’s own U.S. store marked the P55-E2 sold out, although availability on Amazon and in other regions may differ. That status can change, so use the exact Amazon listing to confirm current stock and seller information.

Anker supports a higher price with its longer retractable cable, display, slightly faster input and better multi-device distribution. INIU counters with a lighter design, detachable lanyard, phone holder, flashlight and three-year INIU Care. Current price decides the better value.

• Check the current Anker Nano A1638 price on Amazon.com
• Check the current INIU P55-E2 price on Amazon.com

Who should buy the Anker Nano A1638?

Buy the Anker Nano A1638 if most of these statements describe you:

• You want a retractable cable long enough to use a phone comfortably while charging.
• You prefer a detailed display instead of simple battery lights.
• You sometimes charge two or three devices and want the higher combined-output limit.
• You want up to 30W input and the convenience of two-way charging through the built-in cable.
• You prefer a short, narrow power bank even if it is thicker and heavier.

The A1638 is the stronger recommendation when convenience matters more than the lowest price. Its main disadvantage is its thicker, heavier body.

Who should buy the INIU P55-E2?

Buy the INIU P55-E2 if most of these statements describe you:

• You want a thin, light bank that fits more naturally beside a phone.
• You prefer a detachable USB-C cable that doubles as a lanyard.
• You value the phone holder, emergency flashlight and three-year INIU Care.
• You normally charge one device at a time, so the 15W multi-device limit is not a major concern.
• The P55-E2 is available from a reputable seller at a meaningfully lower price.

The P55-E2’s main weaknesses are its short cable, lower shared output and uncertain stock at the time of editorial review.

Frequently asked questions

Is the Anker Nano A1638 faster than the INIU P55-E2?

Not for a single compatible device based on the advertised maximum: both list up to 45W USB-C output. The Anker is stronger when multiple devices are attached because it lists up to 22.5W combined output, compared with the INIU’s 15W total. Actual charging speed depends on the device and protocol.

Which power bank is smaller?

The Anker is shorter and narrower, but the INIU is much thinner and about 1.7 ounces lighter. INIU is usually the more pocket-friendly choice, while Anker may fit better in a compact accessory pouch.

Which has the better built-in cable?

The Anker’s approximately 2.3-foot retractable USB-C cable is better for reach and clutter-free storage. The INIU’s 0.4-foot cable is better if you want a compact, detachable lanyard that can be replaced more easily.

Final verdict

In the Anker Nano A1638 vs INIU P55-E2 comparison, the Anker Nano A1638 is the better overall choice for convenience and versatility. Its longer retractable cable, informative display, 30W input and higher shared-output ceiling make it easier to recommend for everyday charging and occasional device sharing.

The INIU P55-E2 is the better slim-value alternative. It is lighter, thinner and rich in extras, and its listed 45W single-device output matches the Anker. Buy it when you normally charge one product at a time, like the detachable lanyard design and can find the exact model at a clearly lower price from a reputable seller.

Before purchasing, compare the current price, availability, seller, warranty terms and full model number. Do not substitute a similar-looking 10,000mAh product, because cable design, protocol support and shared-output limits may differ.

Continue Reading

• 5 Best Power Banks Under $50
• Best Fast-Charging USB-C Power Banks
• 5 Best Slim and Compact Power Banks for Travel
• Why Is My Power Bank Charging Slowly? 9 Causes and Fixes

Sources

• Anker: Nano Power Bank A1638 product specifications
• Anker Support: Understanding the maximum charging power of the A1638
• INIU: P55-E2 product specifications
• Federal Aviation Administration: PackSafe lithium-battery guidance
• U.S. Consumer Product Safety Commission recall database