You’ve probably been there — scrolling through Shopee or standing at a Challenger shelf, trying to figure out which power bank is “good.” Some are slim, others are huge bricks. Some cost $30, others $90. And every single one throws technical terms at you: mAh, Wattage, PD, USB-C, QC… confusing, right?
We get it. You just want something that can charge your phone a few times without weighing down your bag or exploding. So let’s break it down — clearly, simply, and with zero jargon overload — so you know exactly what to look for next time you’re shopping for one.
Editor
Lloyd Kelly Miralles chevron_right
Table of Contents
What Does mAh Really Mean?
Let’s start with the number you see most: mAh.
mAh = Milliamp-Hour
It’s a measure of how much total energy a power bank can store. In theory, the higher the number, the more times it can charge your phone.
But here’s the catch — it’s not 100% efficient. A power bank labeled 10,000mAh doesn’t give you ten thousand actual milliamp-hours of usable power. You typically get around 60–70% of that due to energy lost in voltage conversion, heat, and cable resistance.
Real-world estimates:
|
Power Bank Capacity |
Usable Power |
Typical Phone Charges |
|
5,000mAh |
~3,000–3,500mAh |
1 full charge |
|
10,000mAh |
~6,000–7,000mAh |
1.5 to 2 charges |
|
20,000mAh |
~12,000–14,000mAh |
3 to 4 charges |
|
30,000mAh |
~18,000–21,000mAh |
5+ charges |
Don’t just go for the biggest number. Match the capacity to how often you’re charging and what devices you’re using.
What About Wattage? (This Is Where Speed Comes In)
While mAh tells you how much energy is stored, Wattage (W) tells you how fast your device will charge.
Wattage is calculated as Voltage × Current. Higher wattage = faster charging.
General recommendations:
|
Device |
Ideal Charging Speed |
|
Budget smartphones |
10–18W |
|
iPhones (recent models) |
18–30W (PD) |
|
Android flagships |
25–45W (PD/PPS) |
|
iPads/Tablets |
30–45W |
|
USB-C laptops |
45–100W |
If you want fast top-ups, don’t just look at capacity. Make sure your power bank offers enough output wattage for your device.
The Ports: What to Know
The number and type of ports matter more than people think.
USB-A
The older, rectangular port. Still common, but often limited to slower charging.
USB-C
The current standard for phones, tablets, and laptops. Supports both input and output and enables fast charging when paired with PD or PPS.
Input vs. Output
- Input: Used to charge the power bank itself
Output: Used to charge your devices
Many USB-C ports support both, which is called two-way charging — very convenient for travel.
Fast Charging Standards: What They Mean
You’ve likely seen PD, QC, or PPS mentioned on packaging. Here’s what matters:
- PD (Power Delivery): The most common fast-charging standard via USB-C. Supported by iPhones, iPads, laptops, and most Android phones.
- QC (Quick Charge): Qualcomm’s older tech, used on many Android phones. Still works, but not as universal.
- PPS (Programmable Power Supply): A smarter version of PD that adapts power delivery in real time. Especially useful for Samsung devices and battery health.
Bottom line: If you see PD or PPS, you’re getting modern, reliable fast charging.
Handy Features to Look Out For
Some features genuinely improve daily use. Others? Not so much.
Worthwhile:
- Digital displays (better than blinking dots)
- Built-in charging cables (less clutter)
- Pass-through charging (charge your phone and power bank at the same time)
- Low-current mode (for earbuds and wearables)
Skip if you don’t need:
- Wireless charging (cool, but slower and less efficient)
- Solar panels (very slow unless you're hiking)
- Flashlights (not a dealbreaker either way)
How Long Does It Take to Recharge a Power Bank?
This is something many people forget to ask — how long does it take to recharge the power bank itself?
It depends on:
- The capacity
- The input wattage
- The charging method (USB-A or USB-C)
For example:
- A 20,000mAh power bank with a 10W input may take 8–10 hours to fully recharge.
- A power bank with 20W PD input may charge in under 5 hours.
If you’re always in a rush or forget to charge overnight, look for power banks with fast input via USB-C PD (ideally 18W or more). It makes a huge difference.
Flight Safety: What’s Allowed on Planes?
If you travel, especially internationally, you’ll want to make sure your power bank is flight-safe.
Most airlines (including Singapore Airlines and budget carriers like Scoot or AirAsia) follow these general rules:
- Power banks must be under 100Wh (about 27,000mAh)
- Anything above must be declared and approved
- Must be carried in hand luggage, not checked baggage
Always check the label or product listing — some will clearly say “flight safe” or “under 100Wh.” If not, here’s a quick formula to calculate:
Wh = mAh ÷ 1,000 × Voltage (most are 3.7V)
So a 20,000mAh power bank = roughly 74Wh, which is safe to bring onboard.
Are All Cables the Same? (Hint: No.)
You could buy the best power bank in the world — but if your cable can’t handle fast charging, none of it matters.
Look for:
- E-marked USB-C to USB-C cables (for higher wattage like 60W or 100W)
- PD-compatible cables for iPhones (USB-C to Lightning, certified)
- Durable braided or reinforced cables if you’re constantly on the go
Avoid ultra-cheap cables with no specs or branding. They often charge slowly or fail within weeks.
What Power Bank Should You Get?
Let’s match specs to your lifestyle:
For casual daily use, a 10,000mAh power bank with one USB-C PD port (around 20W) is compact, light, and perfect for keeping your phone alive through the day.
For frequent travellers or multitaskers, a 20,000mAh model with USB-C and USB-A ports, around 30–45W output, and fast input charging will give you more flexibility to charge phones, tablets, and earbuds.
For remote workers or those charging laptops, go for a 25,000–30,000mAh unit with USB-C PD output of 65W or higher, at least two output ports, a digital display, and two-way fast charging. Just be aware it’ll be heavier and bulkier.
Conclusion
Power banks may all look similar, but the right one for you depends on more than just size. By understanding mAh, wattage, port types, and charging protocols, you’ll make smarter choices — and avoid buying something that doesn’t meet your needs. Always start with how you actually use your devices, then let the specs guide you. The rest? Just extra.