How Long For Anker Power Bank To Charge? | Fast Guide

Here’s a clear way to plan your top-up. Charge time comes down to three things: the battery size inside the pack, the input power it accepts, and the wall charger plus cable you plug in. Match these well and a medium pack can refill in a short evening. Pair them poorly and a big pack might still be sipping power at breakfast.

Charging Time For Anker Power Banks — What Affects It

The timing isn’t a mystery. It follows a simple pattern. Bigger batteries hold more energy. Higher input watts push energy faster. Good chargers and cables keep that speed steady. The last few percent slow down to protect the cells. Put those pieces together and you can predict the window with solid confidence.

Battery Capacity (mAh And Wh)

Capacity on the box is in milliamp-hours. Inside the pack, cells sit near 3.6–3.7 volts. To compare sizes across models, convert to watt-hours: Wh ≈ (mAh × 3.7) ÷ 1000. A 10,000 mAh unit is about 37 Wh. A 20,000 mAh unit sits near 74 Wh. More watt-hours means more time to refill at the same input power.

Input Power And USB-C PD

Modern packs take USB-C Power Delivery. The higher the supported input wattage, the quicker the refill. Entry models accept around 10–15 W. Many mid packs accept 18–30 W. High-end laptop-grade units accept far more. USB-C PD also manages the last-stage taper smoothly, which trims wasted time and heat. For the standard itself, see the USB-IF’s overview of USB Power Delivery.

Wall Charger And Cable Quality

Your wall brick sets the ceiling. If the bank wants 20 W in, but the brick only gives 10 W, you’ll wait longer. The cable matters too. A worn or low-spec cable can cut the input below the target. Use a solid USB-C to USB-C cable rated for the amps your charger delivers.

Battery Level, Taper, And Passthrough Use

From empty to roughly 80%, charging is brisk. Near full, the bank slows the current to protect the cells. Also, if you charge the pack while it powers a phone, the refill time stretches. Unplug devices when you want the fastest top-up.

Fast Estimates For Popular Sizes

This table gives practical windows based on typical inputs many packs accept. Times include the natural taper near full. Real results vary by model, charger, and cable.

Bank Size	Common USB-C Input	Empty-To-Full Time (Est.)
10,000 mAh (~37 Wh)	10 W / 20 W	~4–6 h / ~2–3.5 h
20,000 mAh (~74 Wh)	18 W / 30 W	~6–8 h / ~3–4.5 h
24,000 mAh (~89 Wh)	30 W / 60–100 W*	~4–5.5 h / ~1.3–3 h*

*High input figures apply to select high-end units that support elevated PD input. Always check the product page for the exact input limit.

How The Math Works (So You Can Predict Yours)

You can estimate time with a quick back-of-the-envelope. Use this when shopping for a charger or when you’re packing for a trip and need a plan.

Step 1: Convert To Watt-Hours

Multiply mAh by 3.7 and divide by 1000. That gives a decent Wh estimate. A 20,000 mAh unit is about 74 Wh.

Step 2: Divide By Real Input Power

Use the input wattage your bank supports and your brick can supply. If your bank accepts 18 W but your brick only offers 10 W, the real input is 10 W. If both do 20 W, use 20 W.

Step 3: Add A Taper Margin

Multiply the result by ~1.15–1.3 to account for taper and overhead. That covers the slower top-off and conversion losses inside the pack.

Worked Example

Bank: 20,000 mAh → ~74 Wh. Charger: 20 W. Base time: 74 ÷ 20 = 3.7 h. Add 25% margin: 3.7 × 1.25 ≈ 4.6 h. So plan on about 4.5–5 h.

What Real Models Show In Practice

Brand guidance lines up with those estimates. One 20,000 mAh unit lists a full refill in about 6.5 hours with an 18 W PD charger. That figure reflects a conservative margin and the taper near full. You can see that note in the maker’s article for the 20K “335” series under “Recharging time.” Here’s the official reference: Recharging time: 18 W PD ≈ 6.5 h.

Higher tiers that accept strong PD input can shorten the wait. A laptop-grade unit near 24,000 mAh with high input support can move from low to high percent in a short session when paired with a matching charger and a capable cable. If your model’s page lists a specific input wattage, that number is your best anchor for planning.

Pick The Right Wall Charger

Use a charger that meets or beats your bank’s USB-C PD input rating. A little headroom is fine. Going far above the bank’s input limit doesn’t force extra speed; the bank will only take what it’s designed to accept. The table below shows how charger choice shifts the window for two common sizes.

Charger Output	10,000 mAh Bank	20,000 mAh Bank
10 W USB	~4–6 hours	~8–12 hours
20 W USB-C PD	~2–3.5 hours	~4.5–6 hours
30 W USB-C PD	~1.8–3 hours	~3–4.5 hours

These windows assume healthy cables, room-temp charging, and no passthrough use.

Tips To Charge Faster Without Stress

Use A PD-Rated USB-C Cable

Match the cable to the amps you expect. If your charger does 20 V at 3 A, use a cable rated for that. Loose connectors add resistance and heat, which can drop input power.

Let The Pack Breathe

Heat slows charging and ages cells. Keep the bank on a hard surface. Don’t sandwich it under bedding or a laptop sleeve while it’s refilling.

Avoid Passthrough During Refills

Charging the bank and a phone at the same time extends the session. If you’re in a hurry, charge the bank alone first. Then top up the phone from a fuller pack.

Top Off Around 20–30%

Plugging in before it’s stone-empty trims the time you spend near the slow tail at the end. That can make your routine feel snappier day to day.

Troubleshooting Slow Sessions

Check The Brick’s Label

Many slow cases trace to an old 5 V / 2 A charger. Swap in a USB-C PD brick with the watts your bank supports. Watch for multiple outputs on the label, then pick the USB-C PD port.

Swap The Cable

A flaky or low-grade cable can cap current. Try a short, known-good USB-C to USB-C cable. If input jumps, you’ve found the drag.

Test A Different Outlet

Shared power strips and travel adapters sometimes sag. A wall outlet gives a steadier feed. If the pack warms up more than usual, let it cool and try again.

Watch The Last 10%

That final stretch is always slower. If you only need a day out, stopping at 90% can save time with little tradeoff.

When A High-End Bank Charges Fast

Premium models with high PD input can refill rapidly when paired with the right brick and cable. Some laptop-grade units accept input well above 60 W. In that tier, a short session can add a large chunk of capacity. The catch: the wall charger must match the bank’s input profile, and the cable must carry the amps. If either part falls short, the pack will step down to a lower level and the window widens.

Travel Notes For Flyers

Airlines keep portable batteries in the cabin, not in checked bags. If you pack a large unit for a long trip, confirm the watt-hour rating on the label before you fly. Most everyday packs sit under 100 Wh, which fits common rules for carry-on. Oversize units may need airline approval. If you want the formal rule set from the source, check the FAA’s page on lithium batteries.

Quick Model-Picking Advice

Match the bank to your routine. If you carry a phone and buds, a 10,000 mAh pack with 20 W input hits a sweet spot: light, pocketable, and quick to refill. If you power a tablet or switch, 20,000 mAh with 30 W input gives headroom and trims overnight waits. For light laptop boosts, step to a high-input, high-output unit and pair it with a capable PD wall charger.

Simple Planner You Can Trust

Pick size by watt-hours, not just mAh. Check the bank’s USB-C input spec. Buy a wall brick that can meet that input on a single port. Use a sturdy USB-C cable. With that trio lined up, your nightly refill will fit a normal evening window, and a midday top-up becomes easy during lunch.

Reference Points You Can Use

For a concrete anchor, that 20K “335” series shows about 6.5 hours with an 18 W PD charger in the maker’s guide (linked above). Many 10K banks land near 4–6 hours on a 10 W brick and 2–3.5 hours on a 20 W brick. Bigger laptop-class units shorten the wait only if the model supports high input and you bring the right charger. If your current setup feels slow, the fastest lift usually comes from upgrading the wall brick to match the bank’s input rating.

Method Notes

The tables here smooth out model quirks and round to practical windows. They factor in conversion losses, taper near full, and normal cable drop. Ambient heat, active passthrough use, and background battery management can stretch times. When precision matters, rely on the exact input spec on your model page and calculate with the short formula above. That gives a plan you can count on before a trip or a busy day.

Final Take

Charge time boils down to size, input watts, and the gear in your outlet. Pair a bank’s USB-C PD input with a matching wall charger and a strong cable, and even a roomy pack refills in a manageable window. Miss on any piece, and hours stack up. With the tables, math steps, and links above, you can dial in a setup that fits your day and keeps your gear ready.