Planning to buy power bank? Know which one suits best:Check these 5 things before choosing the right one for your phone, tablet, or laptop

A power bank has become an everyday essential for millions of Indians, whether it’s for commuting, travelling, working remotely, or dealing with power cuts. But buying one isn’t as simple as picking the biggest battery or the cheapest option. Safety experts and consumer advisories have repeatedly warned that poor-quality power banks can overheat, swell, or even catch fire due to faulty batteries and internal short circuits. Before you buy one, here are the five things that actually matter. 1. Safety comes before price The first thing to check is BIS certification. In India, power banks should carry the Bureau of Indian Standards (BIS) or CRS certification mark, which indicates the product has been tested for safety standards such as protection against overcharging, overheating, and short circuits. A power bank may look identical on the outside, but uncertified products often compromise on battery quality and internal protection circuits. Spending a little more on a certified device is usually the safer choice. What to check on the box: BIS/CRS certification, warranty, and safety protection features. 2. Choose the right capacity for your lifestyle The mAh (milliampere-hour) rating tells you how much power a power bank stores. However, the printed number is not the exact amount your phone receives. Around 15–30% of energy is lost during voltage conversion, so the usable capacity is always lower than the advertised capacity. A 10,000 mAh power bank is suitable for everyday users, making it a practical choice for office, college, and daily commuting. Depending on the phone’s battery size and energy losses during charging, it can generally provide around two full charges. A 20,000 mAh power bank is better suited for frequent travellers and people who need more backup. It can be useful during long journeys, vacations, or power cuts, especially when you need to charge multiple devices. If you travel regularly, a 20,000 mAh model is generally the more practical option because it can charge your phone several times and also power accessories like earbuds or smartwatches. 3. mAh and wattage are not the same thing This is where many buyers get confused. mAh tells you how much power the battery stores. Watt (W) tells you how fast it can charge your device. A high-capacity power bank with low wattage may still charge your phone very slowly. If your smartphone supports 25W charging, buying a 10W power bank means you won’t get its maximum charging speed. Also read: Want to buy a smartphone, but looking for something new?: Top 5 phones launching in October 2026 with 10,000mAh batteries and premium cameras

4. Different types of power banks serve different needs For most buyers, a USB-C power bank with both input and output ports offers the best compatibility with modern devices.
5. If you fly often, know this important rule Power banks are allowed on flights, but only in cabin baggage. Never place them in checked luggage. Airlines require passengers to carry power banks in their hand baggage so that any battery-related issue can be identified and handled quickly if necessary. It’s also advisable to avoid leaving a charging power bank unattended during a flight.
How does a power bank work?
A power bank is essentially a rechargeable battery combined with electronic circuits that control how electricity enters and leaves the device. – Battery cells store the energy
Most power banks use lithium-ion or lithium-polymer battery cells. When you plug the power bank into a charger, electrical energy is stored chemically inside these cells. – A charging circuit controls incoming power
The circuit inside the power bank regulates the electricity coming from the wall charger. It prevents the battery from receiving unsafe amounts of current or voltage. – The battery stores power at a different voltage
A typical lithium battery cell operates at around 3.7V nominal voltage, while USB devices generally charge at around 5V or higher. – A converter increases the voltage
When you connect your phone, the power bank’s DC-DC boost converter increases the battery’s voltage to the level required by the USB output. For example: Battery → ~3.7V → Boost converter → 5V/9V/12V etc. → Phone For fast charging, the power bank and phone can negotiate higher voltages and currents through standards such as USB Power Delivery (USB-PD). – The USB port sends the power to your device
The output circuit delivers the appropriate voltage and current through the USB cable. Your phone then uses that electricity to charge its own battery.
Popular power banks available in India These are widely available examples across different categories, not ranked recommendations. A power bank is a safety device as much as a charging accessory. Choosing the right one means looking beyond price and focusing on certified quality, suitable capacity and the charging speed your devices actually need.