30,000mAh and Over Power Banks

For days away from a plug

Power banks of 30,000mAh and over are the largest in the shop. They are for several days away from power: camping, a long trek, a boat, a festival without a charging tent, or keeping the household's phones going in a power cut. They are heavy, and they take a long time to fill, so they are a power bank for a rucksack or a cupboard, not a pocket. This page lists the power banks whose own name or description gives 30,000mAh or more.

What is here

Today the page holds a 30,000mAh power bank with a cable built in and a display showing how much charge is left, with 22.5W fast charging. The built-in cable means there is one less thing to pack, and the display saves guessing whether it was filled before the trip. It is also offered at 20,000mAh and 10,000mAh from the choices on its page, for anyone who wants the same design lighter. For other big power banks, including solar ones for camping, see high-capacity power banks and solar power banks.

What 30,000mAh really gives

The mAh on the box is measured at the cells, at about 3.7 volts, and roughly two-thirds reaches the phone, the figure Anker uses in its worked example. So a 30,000mAh power bank gives about 20,100mAh to a phone: about five full charges of a phone with a 4,000mAh battery, or a few days of top-ups for two people. It holds about 111Wh.

Flying with a big power bank

Power banks go in your hand luggage, never in a checked bag. The UK Civil Aviation Authority allows two per passenger, they must not be recharged on board, and each should be in a pouch or its packaging so its sockets cannot touch keys or coins. The limits are in watt-hours: under 100Wh is allowed in the cabin, 100Wh to 160Wh needs the airline's approval, and over 160Wh is not allowed in passenger baggage. A 30,000mAh power bank with 3.7-volt cells works out at about 111Wh, over 100Wh, so it needs your airline's approval before you fly. Read the watt-hours printed on your own, as cell voltages vary and the printed figure is the one that counts. Check your airline's own rules as well, as some are stricter.

Questions people ask about 30,000mAh power banks

How long does it take to fill?

Many hours, so start the night before. A big power bank fills fastest from a USB-C charger with USB Power Delivery; an old 5-volt cube can take most of a day. The guide to power banks explains the sum.

How should I keep one for power cuts?

Apple's advice for its own devices is to store a battery about half charged, somewhere cool, and top it up every six months, which suits a power bank kept for emergencies. Never charge a swollen, damaged or hot one, and charge it uncovered, not overnight or while you are out, as Electrical Safety First advises.

How long does delivery take?

Delivery is included in every price and tracked to your door. Each product page says when it usually arrives.

More to look at

• 20,000mAh power banks
• High-capacity power banks
• Solar power banks
• Hand-crank chargers
• Power banks with built-in cables
• Guide: Power banks explained: mAh, real capacity and flying with one