Charge Your Laptop with a Portable Charger: Understand mAh and Watts

With hybrid work on the rise and travel becoming part of daily life again, keeping your laptop charged on the go is more essential than ever. But can you really charge a laptop with a portable charger? In this guide, we'll break down the technical side of portable laptop charging, including what mAh and watts mean, how much your laptop actually needs, and how to select a good power bank for laptop use.

Can You Really Charge a Laptop with a Portable Charger?

Yes, but not all portable chargers are made equal. While most portable chargers are designed for phones, tablets, and smaller gadgets, a portable charger to charge laptop devices needs to meet specific output requirements—particularly in wattage and port compatibility.

Laptops typically require higher power delivery (PD) than phones. Most modern laptops like MacBooks, Dell XPS, or Lenovo ThinkPads need anywhere from 30W to 100W of power depending on the model and workload. That means the laptop powerbank you choose must support high wattage output and feature USB-C PD ports capable of delivering this performance.

What Is mAh and Why It Matters

mAh (milliamp-hours) is a measure of capacity—it tells you how much charge a battery can store. A higher mAh rating generally means more charging cycles or runtime for your devices.

For instance:

A 20000 mAh laptop power bank can typically deliver between 50–75Wh of energy.

That's enough to charge a typical MacBook Air (50Wh battery) about 1 times.

For power-hungry models like the MacBook Pro 16" (100Wh battery), a single charge might not be possible, but it could offer substantial runtime extension.

Keep in mind: Real-world performance is affected by conversion losses and the wattage demand of your laptop during usage.

What Is Wattage (W) and Why It's Crucial

Wattage measures power output (Watts = Volts × Amps). It tells you how fast energy is delivered to your device. For charging laptops, wattage is more important than mAh in determining whether a power bank is even capable of charging your device.

Typical laptop wattage needs:

• MacBook Air: ~45W
• MacBook Pro 13-inch (Intel/Apple Silicon): ~60W
• MacBook Pro 14-inch (M1 Pro): 67-96W
• MacBook Pro 16-inch (M1 Max): 96W ~ 140W
• Dell XPS 13: 45–60W

So, a high-wattage power bank with at least 65W output is the minimum you should consider for universal laptop charging. If you’re using more specialized equipment, look for a higher power output.

mAh vs Wattage: Understanding the Definition and Choosing Right

To put it simply:

• mAh = how much energy the power bank stores
• Wattage = how fast it delivers that energy to your laptop

Choosing the best laptop powerbank means balancing these two:

• High mAh ensures your device can be recharged fully at least once.
• High Wattage ensures your laptop can be charged efficiently and safely.

Think of it like filling a water tank:

• mAh is the tank size.
• Wattage is the size of the pipe delivering water.

How Much mAh and Wattage Do Laptops Actually Need?

Let's use MacBooks as reference points:

MacBook Model	Battery Capacity	Required Wattage	Recommended Power Bank Specs
MacBook Air	~50Wh	30W	20000mAh / 30W+ PD output
MacBook Pro 13”	~58Wh	61W	20000–25000mAh / 65W+ PD output
MacBook Pro 14”	~70Wh	67W	25000mAh / 65–100W PD output
MacBook Pro 16”	~100Wh	96W–140W	25000+mAh / 100–140W PD output

Note: FAA regulations limit portable battery packs on planes to 100Wh (approx. 27000mAh at 3.7V). Always check the Wh rating before boarding with a high-capacity power bank.

How to Choose the Best Power Bank for Your MacBook or Other Laptop

When choosing a portable charger to charge your laptop, here are the key features and specs to consider:

1. USB-C Power Delivery (PD) Output

Make sure the power bank supports USB-C PD with a minimum output of 65W. This is essential for charging most modern laptops, including MacBook Air, Dell XPS, and Lenovo ThinkPad.

For better performance, choose models that also support Programmable Power Supply (PPS), which provides adaptive voltage adjustment—especially beneficial for Samsung Galaxy devices and other PPS-enabled phones or tablets.

2. High Capacity: 20,000 mAh or Above

A 20,000 mAh battery typically delivers enough capacity for at least one full charge of a MacBook Air, and can extend the runtime of larger laptops like the MacBook Pro or Surface Laptop.

If you often work on the go or need multiple charges, consider going even higher—such as a 25,000 mAh or 30,000 mAh laptop power bank.

3. Multiple Output Ports for Versatility

A good laptop power bank should include:

• At least one USB-C PD port (ideally bi-directional for charging and recharging)
• Additional USB-A ports for charging smaller devices like smartphones, Bluetooth earbuds, or accessories

Optional: Pass-through charging support, so you can power your devices while the power bank is charging (though not all models support this reliably)

4. Smart Display & Advanced Safety Features

Look for models that offer:

• Digital LED or OLED status screens that show real-time output wattage, remaining battery percentage, or time to full charge
• Built-in safety mechanisms such as:
• Overheat protection
• Overcurrent and overvoltage protection
• Smart battery management systems (BMS) to extend battery lifespan and protect your laptop

5. Trusted Brand Backing

Quality and safety are critical when powering high-value electronics like laptops. Stick with reputable manufacturers like INIU, Anker, or UGREEN, which offer:

• Certified safety standards (e.g., UL, CE, FCC)
• Reliable customer support
• Clear warranties and product registration
• Consistent user reviews from verified buyers

As the No.1 portable charger brand on Amazon, INIU has earned the trust of consumers worldwide over the past decade. Our industry-leading 3-year warranty and 15 Smart Protect features ensure your safe charging.

FAQ

Q1: Can I use a phone power bank to charge my laptop?

This depends on the output power of your mobile phone power bank. Most phone power banks output 18W or 20W, which is too low for laptop charging. You need a high wattage power bank (at least 45–65W). In addition, most of the new high-power power banks now have intelligent power distribution functions, which will only provide your devices with the power they can support, so you can use high-power power banks to charge small devices such as mobile phones.

Q2: Will a 20000mAh power bank fully charge my MacBook?

For smaller models like the MacBook Air—yes, nearly once. For larger Pro models, expect 50–70% depending on your usage during charging.

Q3: What's the best portable charger to charge a laptop on a plane?

Look for a 20000–27000mAh model with <100Wh energy rating and 65W+ output to comply with airline regulations and power your laptop effectively.

Q4: How do I know if my laptop supports USB-C charging?

Check your laptop's spec sheet or power adapter. If it uses USB-C (not MagSafe or barrel-type DC), and your adapter is 30–100W, it likely supports USB-C charging.

Power and Capacity Are Both Essential

To charge a laptop with portable charger effectively, you need both high capacity and power output. Don't settle for a basic phone charger—invest in a laptop power bank that offers at least 65W PD output and 20000mAh capacity or higher. With the right combination, you can stay powered up wherever work, travel, or life takes you.