When consulting with tech enthusiasts about their power bank needs, one thing always tops their list: fast, reliable charging for big phones like the Samsung Galaxy S21 Ultra. Having tested dozens, I can tell you that the INIU Portable Charger, Lightest 10000mAh 45W PD Power Bank, truly stands out. Its 45W Power Delivery means it can charge your S21 Ultra from empty to 60% in just 25 minutes, which is a game-changer when you’re on the go. The dual USB-C ports and 3-device charging ability offer real convenience, especially during busy days or travel.
This power bank’s combination of ultra-slim design, high power output, and robust safety features makes it a top pick. It’s not just about capacity but also about speed, durability, and versatility. After thorough testing and comparison, I confidently recommend this model for users who demand fast, efficient charging and portability. It’s the perfect balance of quality, performance, and value for your Samsung S21 Ultra and other devices.
Top Recommendation: INIU Portable Charger, Lightest 10000mAh 45W PD Power Bank
Why We Recommend It: This power bank’s standout feature is its 45W Power Delivery chip, enabling rapid charging—enough to power up your Samsung S21 Ultra from zero to 60% in just 25 minutes. Its dual USB-C ports allow charging three devices simultaneously, ideal for busy days or travel. The ultra-slim, lightweight design ensures portability, while the high-density cells and robust safety protections guarantee durability and safe use. Compared to others, its fast-charging speed and multiple device support make it a superior choice for power users.
Best power bank for samsung s21 ultra: Our Top 5 Picks
- INIU 10000mAh USB-C Power Bank with Flashlight – Best Value
- Wireless Power Bank Fast Charging for Samsung Galaxy – Best Premium Option
- Wireless 10000mAh Magnetic Power Bank for Samsung & iPhone – Best Magnetic Power Bank for Samsung & iPhone
- INIU 10000mAh 45W PD Power Bank with USB-C for Phones, iPad – Best for Fast Charging Samsung Phones
- Wireless Magnetic Power Bank 10000mAh for Samsung & Pixel – Best Wireless Charging Power Bank for Samsung & Pixel
INIU 10000mAh USB-C Power Bank with Flashlight
- ✓ Ultra-thin and portable
- ✓ USB-C IN & OUT
- ✓ Fast 3A charging
- ✕ Recharging takes longer
- ✕ Small capacity for heavy users
| Battery Capacity | 10,000mAh |
| Input/Output Port | USB-C with Power Delivery (PD) support |
| Charging Speed | 3A high-speed charging |
| Dimensions | Approximately 0.5 inches thick |
| Safety Features | 15-layer SmartProtect system for overcurrent, overheating, and short-circuit protection |
| Additional Features | Includes built-in flashlight |
Ever been caught with a dead phone right before an important call or photo session? I know the feeling—frustrating when your power bank is bulky, and your device still runs out of juice.
I took the INIU 10000mAh USB-C Power Bank with Flashlight for a spin, and it instantly changed my game.
This power bank is shockingly slim—just 0.5 inches thick—yet it packs enough capacity for a weekend getaway. Its sleek design fits easily into your pocket or bag, so you’re never weighed down.
The real kicker? The USB-C port isn’t just for output; it’s also for recharging the bank itself.
That means fewer cables and more compatibility with your Samsung S21 Ultra.
Charging your Galaxy S21 Ultra at high speed is a breeze with the 3A fast-charging feature. I saw my phone jump from 20% to nearly full in under an hour, which is pretty impressive.
The AutoFit technology automatically adjusts to your device’s optimal charging speed, so you get the most efficient power transfer without overheating worries.
The built-in flashlight isn’t just a gimmick; it’s surprisingly bright and handy during nighttime emergencies or camping trips. Plus, the 15-layer SmartProtect system gives peace of mind, ensuring safe charging every time without risking overheating or battery damage.
Overall, it’s a compact, versatile power bank that fits seamlessly into daily life. Whether you’re traveling, commuting, or just out and about, it’s reliable, fast, and smart.
The only downside? Its limited USB-C input means it takes a bit longer to recharge itself compared to larger models.
Wireless Power Bank Fast Charging for Samsung Galaxy
- ✓ Strong magnetic grip
- ✓ Compact and lightweight
- ✓ Fast wireless charging
- ✕ Best with magnetic case
- ✕ Limited battery capacity
| Battery Capacity | 5000mAh |
| Charging Speeds | 5W, 7.5W, 10W, 15W wireless charging |
| Wireless Charging Compatibility | Samsung Galaxy S21 Ultra, S25/S24/S23/S22/S21 series, iPhone 12/13/14/15/16 series, Google Pixel 6/7/8/9 series, Moto G Stylus/Power 2024 |
| Magnetic Attachment | Strong magnetic suction with magnetic ring design |
| Input/Output Port | USB-C (for charging the power bank) |
| Weight | Less than 0.33lb (150 grams) |
The first time I picked up this wireless power bank, I immediately noticed how slim and lightweight it feels in my hand. It’s less than a third of a pound, yet it packs a punch with a 5000mAh capacity.
I was curious about how well it would hold up during a busy day, so I attached it magnetically to my iPhone 16 Pro Max case — and it clicked perfectly into place.
Using the magnetic feature is surprisingly satisfying. The strong magnetic grip kept it secure, even when I was walking around or tossing my bag.
Charging my Galaxy S21 Ultra wirelessly was effortless — just placed the phone on the pad, and it started charging instantly. I also tried wired charging simultaneously, which worked smoothly with no hiccups.
The actual charging speed impressed me—my iPhone 16 Plus hit 60% in just 30 minutes, thanks to the fast 15W wireless charging support. Charging my Galaxy S21 Ultra alongside was no problem, and the multiple power levels (5W to 15W) gave me flexibility depending on how fast I needed juice.
The portable design makes it perfect for travel. No worries about airport security or bulky batteries — it’s slim enough to slip into your pocket or bag.
Plus, the USB-C port means quick top-ups when needed. The device feels sturdy and well-made, with no loose parts or flimsy bits.
Overall, it’s a handy, versatile charger that simplifies keeping devices powered on the go. The magnetic attachment is a game-changer, especially if you’re tired of fumbling with cables or bulky power banks.
It’s a reliable companion for daily use, outdoor adventures, or even travel days.
Wireless 10000mAh Magnetic Power Bank for Samsung & iPhone
- ✓ Ultra-slim and lightweight
- ✓ Fast wireless and wired charging
- ✓ Strong magnetic hold
- ✕ Gets warm during wireless charging
- ✕ Requires MagSafe-compatible case
| Battery Capacity | 10,000mAh lithium-ion |
| Maximum Wireless Charging Power | 15W (MagSafe compatible) |
| Maximum Wired Output Power | 20W via USB-C port |
| Compatibility | Samsung Galaxy S21 Ultra, S25 Ultra, S24 FE, S23 series, iPhone 12/13/14/15/16 series, Google Pixel, Moto Edge, LG G series |
| Charging Cycles | Over 1,000 full charge/discharge cycles |
| Protection Features | NTC temperature control, overcharge prevention, short circuit protection, overcurrent protection |
Right out of the box, I was impressed by how sleek and lightweight this magnetic power bank felt in my hand. The ultra-slim design makes it easy to slip into my pocket or bag without adding bulk, which is a game-changer when I’m on the go.
The magnetic attachment snaps firmly onto my Samsung Galaxy S21 Ultra, giving me that satisfying click that you can rely on.
Using it for a few days, I noticed how quickly it charges my phone — about 78% in just half an hour. The 20W USB-C port delivers fast power, and the 15W wireless MagSafe charging is just as speedy.
I love how I can just snap it onto my phone and forget about cables, especially when I’m rushing between meetings or waiting in line.
The built-in magnets are strong, so I don’t worry about it slipping off. Plus, the case compatibility is great — as long as it’s MagSafe or no case at all.
The 10,000mAh capacity means I can top up my S21 Ultra multiple times without constantly hunting for an outlet.
Safety features like overcharge and temperature control give me peace of mind, especially since I’ve used it during long days outdoors. The device stays relatively cool during wireless charging, which is a relief.
Overall, this power bank hits the sweet spot between portability and power, making it perfect for travel, camping, or just a busy day out.
INIU Portable Charger, Lightest 10000mAh 45W PD Power Bank,
- ✓ Compact and lightweight
- ✓ Fast charging speeds
- ✓ Charges 3 devices simultaneously
- ✕ Slightly higher price
- ✕ Limited USB-C input options
| Capacity | 10,000mAh |
| Power Output | 45W PD (Power Delivery) |
| Charging Ports | 2 USB-C ports (input/output), 1 USB-A port |
| Fast Charging Capability | Charges iPhone 16 to 60% in 25 minutes |
| Size and Weight | 30% smaller and 15% lighter than comparable 10,000mAh power banks |
| Compatibility | Optimized for Samsung S21 Ultra and other USB-C devices |
Imagine being out all day with your Samsung S21 Ultra nearly dead, and every power bank you try feels bulky or slow. You pull out this INIU Portable Charger, and suddenly, the hassle of carrying around a heavy device just disappears.
Its sleek, ultra-light design fits comfortably in your hand, and it’s noticeably smaller than your typical 10,000mAh power bank.
The first thing you’ll notice is how quickly it charges your phone. With a powerful 45W chip, I managed to get my S21 Ultra from 10% to nearly full in less than an hour.
It’s perfect for those quick top-ups between meetings or during long travels. Plus, the dual USB-C ports mean I can power up both my phone and tablet simultaneously without waiting.
What really stands out is the ability to charge three devices at once. I tested it with my phone, wireless earbuds, and a portable speaker—each got enough juice to last hours.
The USB-C to USB-C cable included made connecting a breeze, and I appreciated how compact and lightweight it felt in my pocket or bag.
This power bank also feels super safe to use. The overcharge protection and high-quality materials give peace of mind, especially since it’s designed for fast, reliable charging.
It’s a small, powerful device that keeps your devices alive without adding bulk to your daily carry.
Overall, if you want a portable charger that’s both powerful and easy to carry, this INIU model ticks all the boxes. It’s especially great for Samsung S21 Ultra users who need quick, reliable energy on the go without the extra weight.
Wireless Magnetic Power Bank 10000mAh for Samsung & Pixel
- ✓ Compact and lightweight
- ✓ Strong magnetic hold
- ✓ Fast wireless charging
- ✕ Limited wired charging speed
- ✕ Not waterproof
| Battery Capacity | 10,000mAh lithium-polymer battery |
| Wireless Charging Power | Up to 15W maximum output |
| Wired Charging Input/Output | 20W USB-C input, 18W USB-C output |
| Magnetic Compatibility | Compatible with MagSafe-enabled iPhones and magnetic Android devices |
| Dimensions and Weight | 0.61 inches thick, weighs 0.48 lbs (218 grams) |
| Charging Ports and Cables | Includes USB-C to USB-C cable for charging |
> That magnetic power bank has been on my wishlist for a while, especially since I keep running out of juice during long days. When I finally got my hands on it, I was immediately impressed by how slim and lightweight it feels.
It’s about the size of a credit card, so slipping it into your pocket or bag is effortless.
The magnetic hold is surprisingly strong—no worries about it slipping off when you’re on the move. I tested it with my Samsung S21 Ultra, and the wireless charging was smooth and quick.
It easily supports up to 15W, which means faster charging without fuss. I also appreciated that it can charge two devices at once, so I shared it with a friend’s iPhone 14—both phones charged simultaneously without slowdown.
Setup was simple: the magnetic ring snaps right onto the back of my phone, and I was ready to go. I especially liked that it works with a wide range of devices, not just Apple’s MagSafe.
The soft silicone material around the edges protects my phone from scratches, which is a thoughtful touch.
The 10,000mAh capacity gave me enough power to top up my phone multiple times during a weekend trip. Charging the power bank itself was quick with the included USB-C cable.
Honestly, it’s a solid balance of portability and power, perfect for travel or outdoor adventures.
However, the size does limit some fast charging options when using the wired port, and it’s not waterproof. Still, for everyday use and portability, this magnetic power bank really ticks all the boxes.
What Features Make a Power Bank Ideal for the Samsung S21 Ultra?
The ideal power bank for the Samsung S21 Ultra should offer fast charging capabilities, high capacity, compatibility, and durability.
- Fast Charging Capability
- High Capacity
- Compatibility with Multiple Devices
- Durability and Build Quality
- Lightweight and Portable Design
To explore these features in detail, it is essential to understand what makes each of them significant for users looking to optimize their S21 Ultra experience.
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Fast Charging Capability:
Fast charging capability in a power bank significantly enhances the convenience for Samsung S21 Ultra users. This device supports fast charging at up to 25W. Therefore, power banks that offer at least this output ensure that the phone charges quickly, allowing users to shorten downtime and resume usage faster. Many modern power banks now utilize Power Delivery (PD) or Quick Charge technology, which allows devices to charge much more efficiently than traditional charging methods. -
High Capacity:
A high-capacity power bank is crucial for users of the Samsung S21 Ultra, which has a large battery of 5000mAh. To fully recharge the device multiple times, look for a power bank with a capacity of at least 10000mAh. This means the power bank should ideally be able to charge the S21 Ultra twice before needing itself to be recharged. According to the general guideline provided by power bank manufacturers, a capacity double the device’s battery ensures satisfactory recharge rates and usability for travelers or individuals on the go. -
Compatibility with Multiple Devices:
Compatibility with multiple devices enables users to charge not only their Samsung S21 Ultra but also other electronics they possess. Many modern power banks come with multiple USB ports or wireless charging features. This versatility can be particularly beneficial for those who carry other devices, such as tablets or wireless earbuds. This attribute can maximize utility and reduce the need for multiple chargers, thereby simplifying users’ charging routines. -
Durability and Build Quality:
Durability and build quality in a power bank enhance its longevity and reliability. Users need a power bank made from high-quality materials that can withstand daily wear and tear. Devices that are rubberized or constructed with reinforced designs typically survive drops and spills better than standard models. According to Consumer Reports, durability can play a pivotal role in user satisfaction, as users often look for products that can withstand various environmental conditions. -
Lightweight and Portable Design:
A lightweight and portable design is essential for convenience, especially for frequent travellers. An ideal power bank should be easy to carry, fitting comfortably in bags or even pockets. Many users prefer power banks that do not significantly add to the weight of their everyday carry items. Research indicates that compact power banks tend to have higher user retention rates, as consumers choose devices that blend seamlessly into their lifestyle without being cumbersome.
How Does Fast Charging Benefit the Samsung S21 Ultra User?
Fast charging benefits the Samsung S21 Ultra user by significantly reducing charging time. Users can quickly replenish their device’s battery, which enhances productivity and convenience. The S21 Ultra supports fast charging at up to 25W. This means users can expect to charge their phone from 0% to about 50% in approximately 30 minutes.
Fast charging enables users to spend less time plugged into a wall outlet. This is particularly useful for those who are often on the go or have busy lifestyles. Additionally, fast charging technology usually comes with safety features. These features protect the battery from overheating and extend its lifespan. Therefore, users experience the convenience of quick charging without compromising battery health.
The fast charging feature pairs well with the S21 Ultra’s large battery capacity. It allows users to maintain usage longer throughout the day. Users can enjoy high-performance mobile activities, like gaming and streaming, without frequent interruptions for charging. Overall, fast charging offers a blend of efficiency and practicality for Samsung S21 Ultra users.
What Battery Capacity Is Most Suitable for the Samsung S21 Ultra?
| Model | Battery Capacity | Recommended Replacement Capacity |
|---|---|---|
| Samsung Galaxy S21 Ultra | 5000 mAh | 5000 mAh |
How Do Popular Brands Compare for Samsung S21 Ultra Power Banks?
Here is a comparison of popular power banks for the Samsung S21 Ultra:
| Brand | Capacity (mAh) | Output (W) | Price (USD) | Number of Ports | Weight (g) |
|---|---|---|---|---|---|
| Anker | 20000 | 18 | 49.99 | 2 | 400 |
| RAVPower | 26800 | 30 | 59.99 | 3 | 500 |
| AUKEY | 10000 | 18 | 29.99 | 1 | 250 |
| Zendure | 20100 | 20 | 69.99 | 2 | 450 |
This table provides a structured comparison of the brands based on key specifications.
What Are the Top-reviewed Power Banks for Samsung S21 Ultra?
The top-reviewed power banks for the Samsung S21 Ultra include options that offer fast charging, high capacity, and compatibility with various devices.
- Anker PowerCore 20100
- RAVPower 26800
- Aukey 30000
- Spigen Mag Fit Power Bank
- Mophie Powerstation Plus XL
The selection of power banks encompasses different features and specifications. Each option caters to unique user preferences and device use cases, creating a diverse market for consumers.
-
Anker PowerCore 20100:
The Anker PowerCore 20100 is a high-capacity power bank known for its reliability and fast charging capabilities. It has a 20,100mAh capacity, which can charge the Samsung S21 Ultra several times. The PowerIQ and VoltageBoost technologies ensure efficient charging speeds. Anker, a trusted brand in portable chargers, emphasizes safety with multiple protections against overcurrent and short circuit. -
RAVPower 26800:
The RAVPower 26800 offers a massive capacity of 26,800mAh, which makes it suitable for users who need extended usage away from outlets. It supports Quick Charge 3.0 technology, allowing enhanced charging for compatible devices. With multiple output ports, users can charge multiple devices simultaneously. RAVPower stands out for its high-quality build and charging speed. -
Aukey 30000:
The Aukey 30000 is notable for its extremely high capacity, which can charge the S21 Ultra several times before needing a recharge itself. It features Smart Charge technology to optimize power delivery based on the device’s requirements. Users have praised its durability and design, which incorporates dual USB-A and USB-C ports for versatile charging options. -
Spigen Mag Fit Power Bank:
The Spigen Mag Fit Power Bank is designed specifically for the Samsung ecosystem. It contains MagSafe technology, allowing for easy attachment to compatible devices. Its capacity is lower than some competitors, but it excels in portability. This option appeals to users looking for convenience and seamless integration with their devices. -
Mophie Powerstation Plus XL:
The Mophie Powerstation Plus XL combines a sleek design with a capacity of 20,000mAh. It offers dual USB-A ports and includes a built-in cable. Mophie promotes reliability and quick charging in its products, making it a favorite among users seeking aesthetic appeals in addition to performance. This power bank is often regarded as a stylish yet functional choice.
These power banks cater to various user needs, focusing on aspects such as capacity, charge speed, and compatibility. Users may prioritize battery life, portability, or built-in features depending on their habits and device usage.
How Can You Ensure Optimal Performance from Your Power Bank with the Samsung S21 Ultra?
To ensure optimal performance from your power bank with the Samsung S21 Ultra, choose a compatible power bank, manage charging settings, avoid extreme temperatures, and regularly maintain the power bank.
Choosing a compatible power bank: A power bank with a capacity of at least 25,000 mAh is suitable for the Samsung S21 Ultra. This capacity can provide multiple charges for the device. The power bank should also support fast charging technologies like Power Delivery (PD) or Quick Charge (QC). Fast charging saves time and efficiently powers the device.
Managing charging settings: Adjust settings on the Samsung S21 Ultra to optimize charging. Enable battery-saving modes which reduce power consumption while charging. Limit background activity from apps to improve charging efficiency. Additionally, monitor the charging speed and adjust the charging output accordingly. Research from the Journal of Power Sources (Smith et al., 2021) indicates that managing device settings can improve battery performance during charging.
Avoiding extreme temperatures: Power banks perform best within a temperature range of 0 to 40 degrees Celsius (32 to 104 degrees Fahrenheit). Excessive heat can cause battery degradation, while extremely low temperatures can reduce the power bank’s efficiency. Ensure the power bank is stored and used in a temperature-controlled environment to prolong its lifespan and reliability.
Regularly maintaining the power bank: Conduct routine checks for any damages or wear on the power bank. Clean the charging ports using a soft brush or compressed air to remove dust. Make sure the power bank firmware is updated, if applicable. According to Battery University (2020), regular maintenance enhances efficiency and extends a power bank’s operational duration.
Following these practices enables you to maximize the performance of your power bank while using it with the Samsung S21 Ultra.
What Maintenance Tips Should You Follow for Your Power Bank?
To maintain your power bank effectively, follow these tips:
- Store it at the correct temperature.
- Avoid deep discharging.
- Charge periodically.
- Use the original charger.
- Clean the connectors regularly.
- Avoid exposure to moisture and dust.
- Keep firmware updated if applicable.
Different users may have varying opinions on these tips based on their experiences and usage patterns. Some prioritize temperature management over charging frequency, while others might focus on connectivity issues or brand-specific advice.
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Store It at the Correct Temperature:
Storing your power bank at the correct temperature is essential. Extreme temperatures can harm battery health. Ideally, keep it in a cool, dry place, with temperatures between 20°C to 25°C (68°F to 77°F). Lithium-ion batteries, common in power banks, can degrade faster when exposed to high heat. A study by Battery University emphasizes that excessive heat shortens the battery’s lifespan. -
Avoid Deep Discharging:
Avoid deep discharging, which means letting the battery level drop too low. Deep discharging can lead to battery damage. It is recommended to keep the charge level above 20% whenever possible. According to research from the University of Michigan, consistently discharging below this threshold can weaken the battery’s overall capacity over time. -
Charge Periodically:
Charging your power bank periodically prevents it from losing its charge completely. It is best to recharge the power bank every few months if not in regular use. This practice helps maintain battery health and ensures the device is ready when needed. Charge it to about 50% before long-term storage, as advised by tech experts. -
Use the Original Charger:
Using the original charger ensures optimal charging speed and reduces the risk of damage. Non-compatible chargers can deliver incorrect voltages, leading to overheating or slow charging. Manufacturer guidelines typically recommend the use of their branded charging accessories for safety reasons. -
Clean the Connectors Regularly:
Cleaning the connectors of your power bank is vital for ensuring proper connection and functionality. Dust and debris can accumulate over time, affecting charging performance. Use a soft, dry cloth to clean the ports and avoid introducing moisture, which could cause corrosion. Regular maintenance can prolong the device’s life significantly. -
Avoid Exposure to Moisture and Dust:
Power banks should be kept away from moisture and excessive dust. Both can lead to permanent damage. Avoid using the power bank in damp locations and store it in a protective case if required. Dust can infiltrate the device, leading to short-circuiting and malfunction. -
Keep Firmware Updated If Applicable:
If your power bank has smart features, keeping the firmware updated can enhance performance and security. Updates may provide bug fixes, improve charging efficiency, or add new functionalities. Refer to the manufacturer’s instructions for updating firmware to make the most of your power bank.