Power banks are a game changer for charging your phones, tablets, and even your laptops when you're away from a wall socket. But sometimes, those specs can feel like a foreign language. So in this guide, we're going to cover all the bases: mAh, watts, fast charging protocols, and ports. Whether you are a heavy phone user, a voracious traveler, or a digital nomad, you'll be able to find one that suits your lifestyle. Let's dive in.

 

Understanding Power Bank Specs

 

Before you start shopping, let's break down the key specs you'll see on every power bank. These numbers tell you three big things: how much power it holds, how fast it charges your devices, and which gadgets it can handle.

 

Capacity

 

Milliampere-hours (mAh) is the most common spec you'll spot, and it's all about how much energy the power bank can store. A bigger number means more juice to top up your devices. Here's a quick breakdown to help you visualize:

• 5,000mAh: Tiny enough to slip in your pocket and can give your phone a full charge or two quick top-ups.

• 10,000mAh: The sweet spot for daily use. It'll charge most phones 2–3 times.

• 20,000mAh: A workhorse for longer days. It can handle a phone (3–4 charges), a tablet (1–2 full charges), or even power a small Bluetooth speaker for a picnic.

• 30,000mAh+: Suitable for heavy users or long off-grid trips.

Quick heads-up: mAh doesn't translate perfectly to how much charge your device actually gets. Some energy gets lost as heat, so a 10,000mAh power bank might only give your phone 6,000–7,000mAh or usable power. So if you're unsure, it's smart to size up a bit.

 

Input and Output Power

 

If mAh is about "how much", watt-hours (watts) are about "how fast". Watts = voltage (V) × current (A) — but you don't need to do the math. Here's what matters:

• Input wattage: How fast the power bank recharges itself.

• Output wattage: How fast it charges your devices.

Here are some examples:

• 10W: Fine for older phones, but too slow for modern phones.

• 20W: Charges an iPhone 15 Pro 0–50% in about 30 minutes.

• 65W+: Can charge your laptop, perfect for working on the go.

Pro tip: If your phone supports fast charging, get a power bank that matches (or beats) its max speed. Otherwise, even if the power bank says "fast charging," it'll still take forever to juice up your phone.

 

Port Types

 

Charging ports determine which devices you can plug in. Here's a quick guide.

• USB-A: The classic rectangular port. Most older phones, cameras, and small gadgets use this one. Unless labeled "fast charge", it's generally slow.

• USB-C: The newer and now the most popular oval-shaped port. It is way more versatile. It can charge phones, tablets, laptops, and even some cameras. A lot of them support fast charging and can also recharge the power bank itself.

• Lightning: Apple's proprietary port for legacy iPhone models. You don't see this on many power banks, especially newer ones, but it's handy if you don't want to carry extra cords.

 

Fast Charging Protocols

 

Fast charging isn't one-size-fits-all. Your power bank and device need to "speak the same language" to speed things up.

• USB Power Delivery (PD): The most universal protocol. Works with iPhones, iPads, Samsung, Google Pixel, and many laptops.

• Qualcomm Quick Charge (QC): Common in Android phones. QC 3.0/4.0 hits 18W–30W.

• Other protocols: Brands like OPPO, Huawei, or Xiaomi have developed their own fast charging technologies. If you have one of these phones, a power bank that supports their protocol will charge it fastest — but PD still works (just slower).

 

Choosing the Right Power Bank: Find the One That Fits Your Needs

 

Now that you know the specs, let's figure out which power bank is right for you. First, ask yourself some questions: What do I need to charge? How fast? And where?

 

Start with Capacity: How Much Power Do You Need?

• Casual users: A 5,000–10,000mAh power bank is just right. It slips into your purse or pocket without weighing you down and can top up your phone 1– 3 times. Perfect for running errands or grabbing a coffee. Before your coffee gets cold, your phone hits 50%!

• Moderate users: Go for 10,000–20,000mAh. This size can handle your phone and your tablet for a full day out — think music festivals, concerts, or day trips. No more scrambling for an outlet when your phone is dying.

• Heavy users: Got multiple devices to charge? 20,000–30,000mAh is your sweet spot. These power banks are bulkier, but they're workhorses. They can not only keep your phone and tablet powered, and can even refuel your laptop and camera during a business trip or a weekend getaway.

 

Charging Speed: Don't Waste Time Waiting

 

• If you have an iPhone (8 or newer): A 20W PD power bank is all you need. It's fast enough to get you from 0–50% in 30 minutes, perfect for a quick power boost.

• If you have an Android: Look for QC 18W+ or PD 25W+. Flagship Android phones can charge at 45–65W, which means that if you have a 65W PD power bank, you will be able to charge your phone at the maximum speed. No more waiting 2 hours to get a full charge!

• If you need to charge a laptop: Check your laptop's charger first (it'll say something like "65W" or "100W" on it). Grab a power bank with a USB-C port that matches or beats that number. A 65W model works for most thin laptops, while gaming laptops might need 100W or higher.

 

Size and Weight: Portability Matters

 

• Pocket-friendly: 5,000–10,000mAh power banks are lightweight and portable. You'll forget it's there until you need it. Great for daily commutes or nights out.

• Travel-ready: Bigger capacity means more power, but it also means more heft. 10,000–20,000mAh ones strike a nice balance between the two. Stay powered anywhere.

• Heavy-duty: Need a powerhouse for camping or week-long trips? Go with 20,000mAh or higher. They're a bit bulkier, but trust me — totally worth it.

 

Safety Features: Don't Skimp on Protection

 

Never compromise on safety. Look for these must-have safety features:

• Overcharge protection: Stops charging once your device or the power bank itself is full. Some power banks even feature trickle charging mode to keep your device topped up without overdoing it.

• Overheat protection: Shuts down if it gets too hot.

• Short-circuit protection: Prevents damage if a port gets wet or a cord gets frayed.

• Certifications: Labels like CCC, CE, FCC, or RoHS mean the power bank passed safety tests. Skip anything without these.

 

Extras: Nice-to-Have Features

 

• Integrated cables: Ever forgot to bring your cable or brought the wrong one? Power banks that come with cables are your lifesavers!

• Wireless charging: Tired of fumbling with cables altogether? Look for power banks with wireless charging capabilities. Just snap and charge. Pretty cool, isn't it?

• Smart digital display: Shows exactly how much power is left. Stay informed at a glance and never worry about running out of juice when you need it most.

 

Wrapping Up

 

Choosing a power bank doesn't have to be confusing. Start by asking: What devices will I charge? How much power do I need? How fast do I need to charge? Once you have the answers, it will all come together. After all, the best power bank is the one that fits into your life. If you're looking for a reliable option that checks all those boxes, Pisen power banks are worth a spot on your shortlist.

Related Reading: Best Power Banks for Travel: Portable Chargers for Trips