How many charges do you actually get from a 20,000mAh power bank?

The number on the box is the capacity of the cells inside. It is not the amount that reaches your phone. Expect roughly 60 to 70 per cent of it.

Where the rest goes

The cells sit at about 3.7 volts. Your phone charges at 5 volts or higher, so the power bank steps the voltage up, and your phone steps it back down for its own battery. Both conversions lose energy as heat, and fast charging loses a little more than slow charging.

So a 20,000mAh pack realistically delivers somewhere around 13,000 to 14,000mAh.

What that means in phone charges

Most phones sold here carry a 4,500 to 5,000mAh battery. Do the division:

• 20,000mAh → about 2.5 to 3 full charges, not four.
• 27,000mAh → about 3.5 to 4 full charges.

If a listing promises you five charges from 20,000mAh, it is counting the cells, not the phone.

Capacity is not speed

These are two separate numbers and people buy the wrong one all the time.

Capacity (mAh) decides how many charges. Output (watts) decides how fast each one happens, and whether the pack can run anything larger than a phone.

Our Romoss PEA20 (20,000mAh, 30W, Rs 5,000) and Romoss PEA27S (27,000mAh, Rs 7,000) are built for phones and tablets. The Romoss S20 FlashPower holds less than the PEA27S at 20,000mAh and costs Rs 18,500, because it pushes 130W total and will charge a USB-C laptop at a sensible speed. You are paying for output, not capacity.

Picking a size for load shedding

• One phone, a few hours: 10,000mAh is enough, and it fits a pocket.
• A whole day, or two phones: 20,000mAh.
• A family, or a long journey: 27,000mAh, and look for more than one output port so two people charge at once.
• A laptop: capacity is not the question. You need high wattage over USB-C.

One thing to know before you fly

Airlines limit spare lithium batteries in hand luggage to 100 watt-hours without special permission. Convert with: mAh × 3.7 ÷ 1000.

• 20,000mAh ≈ 74Wh — comfortably allowed.
• 27,000mAh ≈ 100Wh — right on the line. Carry it in your hand luggage, never checked, and be ready to show the rating printed on the case.

The short version

Divide the number on the box by three for a realistic count of full phone charges. Then check the wattage separately, because that is what decides whether charging from it feels fast or feels like being tethered to a brick.

All our power banks come with a 15-day warranty and Cash on Delivery anywhere in Pakistan.