Quick answer: Use a power bank from a trustworthy brand, keep it cool, stop using it if it swells, heats strangely or is dented, and never leave it under a pillow or in a hot car. For flights, carry it in hand baggage and check the airline’s limit. Junaid Telecom, Chiniot: ask on WhatsApp 0345 7701965.
What is inside a power bank, and why is safety important?
A power bank is a battery pack, usually made of lithium-ion cells like those in your phone, plus a circuit that manages charging, discharging and protection. Lithium batteries are very useful, but they store a lot of energy in a small space. When one is damaged, overheated or poorly made, it can swell, leak or in rare cases catch fire. Following a few habits keeps the risk very low.
Daily-use rules
- Buy a known brand. Protection circuits make a difference. Unbranded power banks often list high capacity numbers that are not real.
- Use proper cables and adapters. A damaged cable or fake charger can overheat. See our guide on fake chargers.
- Charge on a hard, open surface. Not on a bed, sofa or under a pillow.
- Keep it cool. Don’t leave it on a car dashboard, in direct summer sun, or beside a heater. Heat is hard on any lithium battery.
- Don’t cover it while it works. Avoid wrapping it in cloth or stuffing it in a crowded bag during heavy charging.
- Don’t charge it and charge your phone from it for long hours if it gets very hot. Pause and let it cool.
- Don’t drop, crush or pierce it. Internal damage may not show outside.
- Keep it dry. Water and charging don’t mix. See our monsoon care post.
- Don’t use it with wet hands or in the bathroom.
- Supervise children. Cables and power banks should not be toys.
Warning signs: stop using it if you notice
| Sign | What to do |
|---|---|
| Swelling, bulging case | Stop using it, do not charge, keep away from heat, and dispose of it properly |
| Strong heat when idle | Unplug everything and let it cool away from flammables |
| Burning or chemical smell | Move it away to a safe, non-flammable surface and stop using |
| Dents, cracks, leaks | Stop using |
| Port that sparks or feels loose | Stop using |
| Phone charging very slowly or stopping | Try another cable first, then replace the power bank if it persists |
Do not try to open a power bank. The cells inside can be dangerous if damaged.
Why does my 10,000 mAh power bank not charge my phone ten times?
Capacity labels are measured at the power bank’s internal battery voltage (around 3.7V), but phones charge at 5V or higher. Converting voltage wastes some energy as heat, so real usable capacity is noticeably less than the label. A good power bank is honest about this, while a cheap one may deliver only a small share of its label. If a “20,000 mAh” power bank is suspiciously light and cheap, the number is probably inflated.
How do I convert mAh to Wh for travelling?
Watt-hours (Wh) matter for airlines.
Wh = mAh x battery voltage / 1000
A common cell voltage is 3.7V, so a 20,000 mAh power bank is about 74 Wh. Many airlines allow power banks up to 100 Wh in carry-on without special approval, and need approval for bigger ones, but rules differ by airline and country, so verify with yours before travel. Key points:
- Carry power banks in hand luggage, not checked baggage.
- Keep terminals protected, such as in a pouch.
- Many airlines ask you not to use power banks during flights; follow crew instructions.
How to store a power bank
- Keep it around half charged if you won’t use it for months.
- Store in a cool, dry place.
- Top it up every few months.
- Avoid leaving it plugged in forever.
Choosing a good one
- Look for clear brand name, capacity, input and output ratings printed on the body.
- Check that the output suits your phone, including fast charging if you need it.
- Ask whether the power bank has protection against over-charge, short circuit and over-temperature.
- Compare weight; a very light, big-claimed unit is suspicious.
Junaid Telecom supplies power banks from authorized brands, including Erorex, Biboshi, Ronin and Audionic. Retail customers can buy a single piece at the wholesale price, and rates change daily, so ask on WhatsApp. Warranty follows each brand’s official policy.
Disposal
Don’t throw swollen or damaged power banks in household rubbish or burn them. Keep them in a cool, dry, non-flammable container and ask a local electronics shop where they can be taken.
Visit Junaid Telecom
Junaid Telecom & Repairing Lab, Madrasa Banat Road, Mohalla Garah, Dhol Sikandar, Chiniot. Open daily 8:00 AM to 9:00 PM.
- Owner WhatsApp: 0345 7701965
- Staff WhatsApp: 0348 8651965
- Repairing Lab WhatsApp: 0345 7599995