Sets the ceiling for everything else, since an unmarked one stops at 60 watts whatever the charger.
also: USB cable, charge and sync cable, USB-C cable
The basics
What to know about chargers & power banks
Nothing here charges anything alone
Nothing on this shelf charges anything by itself. The charging circuit that manages the cell lives inside your phone, tablet or laptop, and what you buy is a power supply: a box that turns 120 or 230 volt wall current into low voltage direct current, a cable that carries it, and in a power bank a battery that stores it first. Output is quoted in watts, and a watt is simply volts multiplied by amps, so the old 5 volt 1 amp brick in a drawer delivers 5 W while a modern 20 volt 3 amp adapter delivers 60 W. That one figure, not the size of the box or the color of the cable, decides how fast a battery refills.
Charging is a negotiation
USB Power Delivery, printed as USB PD, turns charging into a negotiation. Two signal wires inside a USB-C connector let the device state what it wants, and the charger replies with a fixed voltage step: 5, 9, 15 or 20 volts, plus 28, 36 and 48 volt steps in the Extended Power Range that reaches 240 W. A layer called PPS, short for Programmable Power Supply, slides the voltage in small increments so a phone can pull more current while making less heat. Gallium nitride, sold as GaN, is a semiconductor that switches faster than silicon and wastes less energy warming the case. So 65 W now fits in the shell that once held 30 W. All of it stops at the cable. Every USB-C cable carries 3 amps as standard. This is 60 W, and anything above that needs a chip in the plug, called an e-marker, declaring the cable good for 5 amps. Feed a 140 W charger through an unmarked cable and you get 60 W, with no warning anywhere.
What mAh actually tells you
Power banks are sold in mAh, milliamp hours, which describes an amount of energy only once you know the voltage behind it. The cells inside sit near 3.6 or 3.7 volts, so a 10,000 mAh bank holds roughly 37 watt hours. Your phone's 5,000 mAh pack sits at 3.85 volts and holds about 19 watt hours. On paper that is two full charges. In your bag it is closer to one and a third, because the bank steps its 3.7 volts up to 5 or 9 to push power out, the phone steps it back down to fill its cell, and every conversion sheds energy as heat. Plan on 60 to 70 percent of the printed capacity reaching the device, and less again over a wireless coil.
Buy for the biggest battery you own
Buy for the heaviest thing you have to fill. A 20 W USB Wall Charger covers any phone; a light tablet wants 30 W, a 13 or 14 inch laptop 65 W, and a large 16 inch machine 96 to 140 W. Households running four devices from one outlet are better served by a Multi-Port Charging Station than by four bricks fighting over a socket. Reach for a 10,000 mAh Power Bank for a long day out, 20,000 mAh for a weekend or two people, and a Magnetic Wireless Power Bank when you want a top-up while still holding the phone. A Wireless Charging Pad earns its place beside a bed, where slow and cable-free beats fast. Long drives need a Car Charger rated 30 W or more, because navigation with the screen lit can drain a phone faster than a weak socket refills it.
Speed costs heat
Speed costs heat, and heat is what ages a lithium cell. Filling a phone at 65 W runs the pack warmer than an overnight 20 W trickle, so keep the fast adapter for the moments you are actually in a hurry. Multi-port models share one power budget rather than giving each socket its rated figure, so a 100 W station may hand 65 W to the first port and drop it to 45 W the moment you fill the second. Wireless charging throws away 20 to 40 percent of the energy as heat in the phone you are trying to protect. Capacity costs weight and rules: a genuine 20,000 mAh bank weighs 350 to 450 g, and lithium batteries above 100 watt hours need airline approval before they fly, with none allowed in checked baggage at all.
Safety mark first, arithmetic second
Judge safety first, then arithmetic. Look for a national safety mark with a listing number behind it, such as UL or ETL in the US, CE and UKCA in Europe and the UK, PSE in Japan or CCC in China, and treat an FCC logo as an interference test rather than a fire one. A power bank must print its watt hour figure on the case, because an airport agent reads that line and not the mAh. Read the power distribution table on a multi-port box instead of the headline number. Weigh the claim: a 20,000 mAh bank that weighs 200 g does not contain 20,000 mAh. On cables, watts and data speed are separate purchases, since a 240 W charging cable can still be a 480 Mbps USB 2.0 cable for files. USB naming is really a mess, so ask for the watt figure and the Gbps figure by number rather than trusting a version.
How to store a power bank
Storage does most of the damage people blame on quality. Park a power bank at 50 to 60 percent when it goes in a drawer, not full and not empty, and wake it every three months, since cells left flat for a year often will not come back. Clear compacted lint from the device port with a wooden toothpick while the device is off, because a plug that cannot seat fully gets misdiagnosed as a dead charger far more often than any other fault. Pull cables out by the plug and never by the lead; the failure is always at the neck. Expect 300 to 500 full cycles from a bank before capacity drops noticeably. A pack that has swollen, bulged or grown warm doing nothing stops being used that day and goes to a battery collection point, never a household bin.
Buyer checklist
Before you buy chargers & power banks
Electronics combine hardware, software and services. Compatibility and support life matter as much as the headline specification.
01
Map the whole setup
Confirm the ports, operating system, network, accessories, apps and services the product must work with.
02
Check the support period
Look for a clear security and software-update policy, especially on connected products and discounted older models.
03
Separate included from subscription
Find out which recording, storage, analytics, content or remote features need an ongoing payment.
04
Plan for repair and data
Check battery and spare-part service, warranty handling, account controls and how personal data can be exported or deleted.
Find the wattage printed on the supply that came with your most demanding device, then match or exceed it. Phones finish at 20 to 30 W, tablets at 30 to 45 W, a 13 or 14 inch laptop at 65 W, and a 16 inch laptop at 96 to 140 W. A charger larger than the device needs is safe, because the device only draws what it asks for.
Convert capacity before you compare power banks. Divide watt hours by the watt hours in your phone, which is usually 18 to 23, then take two thirds of the answer. A 10,000 mAh bank holds about 37 Wh and realistically returns one and a third phone charges, while 20,000 mAh returns closer to two and a half.
Check the airline ceiling before a trip. Lithium batteries up to 100 watt hours, about 27,000 mAh at 3.7 volts, travel in carry-on without permission. Between 100 and 160 Wh you need the airline's approval and are usually limited to two spares. Above 160 Wh they are banned from passenger aircraft. Spare batteries are never allowed in checked bags. Several carriers now also require power banks to stay visible in the cabin rather than in an overhead bin.
Hold a large charger against your actual outlet before buying. A 100 W or higher brick can measure 60 to 70 mm across and block the second socket of a duplex outlet or overhang a power strip by two positions. Folding pins add about 5 mm of depth but survive a bag; fixed pins do not.
Measure the cable run from the outlet to where you sit, not to where the outlet is. Bedside and sofa use needs 2 m. A 3 m cable of thin gauge loses enough voltage that a phone charges at half speed. For a laptop, the cable must be e-marked for 100 W or 240 W or it silently caps at 60 W.
In a car, look up the fuse rating for the 12 volt socket in the owner's manual. Most are fused at 10 to 15 amps, which is a hard ceiling of 120 to 180 W for everything plugged into it. Check whether the socket stays live with the ignition off, since a device left charging overnight can flatten a tired starter battery.
Care
Caring for chargers & power banks
Store a power bank at 50 to 60 percent charge and top it up every three months. Lithium cells self-discharge a few percent a month, and a pack left completely flat for a year can drop below the voltage its protection circuit will restart from, which no charger can undo.
Clean the charging port with a wooden toothpick with the device powered off. Pocket lint compacts into a felt pad at the bottom of the socket, holds the plug 1 mm short of contact, and produces exactly the symptoms people blame on a failing cable or a dying battery.
Unplug cables by gripping the connector, and store them in loose loops rather than tight coils around the brick. Nearly every cable dies at the 10 mm behind the plug where the conductors flex, and a wrapped cable concentrates every bend in that one spot.
Keep chargers and power banks uncovered while they work. A brick under a pillow or a bank inside a packed bag has nowhere to send its heat. Heat is what shortens both the cell and the capacitors inside the adapter. Warm to the touch is normal; too hot to hold for five seconds is a fault.
Wipe a wireless pad's surface and check for anything metal before setting a phone down. A coin, a key or a contactless card between the coils heats up, blocks the charge, and can wipe the card. Also confirm the pad still has the wall charger it shipped with, since many are rated 15 W but sold with no adapter at all.
Retire a battery on the first sign of swelling, a case that no longer sits flat, or heat while idle. Take it to a battery collection point or an electronics recycler. Household waste and hot cars are where damaged lithium cells cause fires, and most municipal bins now refuse them outright.
Questions
Common questions
Why does my phone charge slowly on a charger that says 65 W?
Usually the cable, then the port. An unmarked USB-C cable caps at 60 W and a USB-A to C cable cannot do USB Power Delivery at all. After that, check whether a second device is sharing the charger's budget, whether lint is holding the plug short of contact, and whether the phone is hot, since every phone throttles charging above roughly 35 C.
How large a power bank can I take on a plane?
Up to 100 watt hours, about 27,000 mAh at 3.7 volts, travels in carry-on with no permission needed. From 100 to 160 Wh you need the airline's approval and are usually limited to two. Above 160 Wh it is refused. Spares never go in checked baggage, and the watt hour figure must be readable on the case.
Does fast charging wear out the battery?
Heat does, and speed makes heat. A 20 W overnight charge is gentler than a 65 W refill in twenty minutes. Phones taper the wattage above about 50 percent anyway. Use the fast adapter when you have fifteen minutes before leaving, and the slower one beside the bed. Keeping the pack between 20 and 80 percent matters more than either.
How much of a 10,000 mAh power bank actually reaches my phone?
Around 6,000 to 7,000 mAh in phone terms, so one and a third full charges of a 5,000 mAh handset. The gap comes from voltage conversion: the bank lifts 3.7 volts to 5 or 9 to send power out, your phone drops it back down, and each step loses energy as heat. Over a wireless coil, expect closer to half.
Is wireless charging bad for the phone?
Not bad, just wasteful and warm. Induction loses 20 to 40 percent of the energy, and most of that heat lands in the phone. It suits a nightstand, where eight slow hours cost nothing, and suits a rushed morning badly. Keep the case under about 3 mm thick and remove any metal plate, or the coils will not couple.
Can I charge my phone with my laptop charger?
Yes, on any USB-C charger that uses USB Power Delivery. The phone requests a voltage and current it can handle, and the charger supplies only that. A 140 W adapter will hand a phone its usual 20 to 45 W. The reverse fails: a 20 W phone charger will run a laptop at best and often will not hold the charge against the load.
Is an expensive charging cable worth the money?
Sometimes, for two measurable reasons. Above 60 W a cable needs an e-marker chip to declare 5 amp capability, and that costs real money. Data speed is a separate purchase, since a 240 W charging cable can still transfer at only 480 Mbps. Braided jackets and molded strain relief mainly buy lifespan at the plug neck, which is where cables die.
Do chargers waste electricity when left plugged in with nothing attached?
Almost none now. Efficiency rules cap no-load draw near 0.1 W, which is under 1 kWh a year, or a few cents. Charging a phone daily costs about 9 kWh a year, roughly a dollar or two. The real reason to unplug is a cheap uncertified adapter left unattended, not the bill.
