4 Signs Your Power Bank Is No Longer Safe to Use

We’ve all been there: You’re halfway through a long flight or enjoying a summer hike through the mountains when your phone battery dips into the red zone. Thank goodness you have your trusty power bank with you, because it’s an absolute lifesaver in situations like these. But even though we tend to think of these portable chargers as invincible bricks of infinite energy, whether they are the best wireless or wired power banks, the reality is that they actually have a limited lifespan and must be handled with care, otherwise they can become damaged and become dangerous to use. In fact, if your power bank seems bloated, gets very hot, dies quickly, or is damaged in any way, it is not safe to continue using it.

Beneath the metal or plastic exterior of each power bank is a complex chemical setup, usually powered by lithium-ion cells. These naturally degrade over time. Even a good quality portable charger that withstands years of heavy use will eventually reach the end of the line. But the danger isn’t just that you’ll end up with a dead phone when you need it most: a damaged lithium-ion battery can pose a serious fire hazard that can put your personal safety at risk.

However, a dying power bank often shows physical and functional signs that it is failing. If you want to protect your technology and stay safe, you need to know exactly what to look for. Here are four major signs that your power bank is no longer safe to use.

Easily the easiest problem to spot is a bloated power bank case; in fact, this goes for any battery-powered device, like your phone or laptop. If your power bank can no longer lie perfectly flat on a table, or if the case appears expanded or cracked along the seams, you should stop using it immediately. Do not plug it into an outlet, and especially do not plug your smartphone into it. This swelling is caused by a buildup of dangerous gases inside the lithium-ion cells. And the internal components of the battery deteriorate over time, usually from overcharging, extreme temperatures in some way, or simply old age.

This buildup of pressure causes swelling, which will eventually push outward at the bank case, and this will only last for a while. If punctured or subjected to further stress, a swollen battery like this can easily catch fire or explode. For the record, there is no way to save a battery in this state; it’s a lost cause. If you notice a slight curve on your previously flat power bank, it becomes an active hazard.

When you have a lithium-ion battery that you no longer need, especially if it is damaged or swollen, the Environment Protection Agency states that “these batteries should not be disposed of in household trash or recycling bins.” And that, to dispose of them properly, they “must be deposited in recycling or household hazardous waste collection centers” that the agency recommends on its website.

It is completely normal for a power bank to warm up slightly while charging devices or when being recharged from a wall outlet. Electric current in motion naturally generates some heat, especially for fast charging. However, there’s a big difference between that expected gentle warmth and a device that becomes uncomfortably hot to the touch. If a battery bank gets so hot that you hesitate to hold it, or if it feels like it’s going to burn other materials, something is definitely wrong internally.

This extra heat often means that the internal resistance of the battery has skyrocketed. High-quality power banks typically work with built-in thermal sensors that turn them off if temperatures get too high. This is one of the reasons why external batteries continue to catch fire on airplanes. If your charger gets hot, it means these crucial safety mechanisms have failed or never existed.

Continuing to use an overheating external battery is a bad idea, as it either accelerates existing internal problems or creates new ones. Intense heat like this also passes through the charging cable, which can permanently damage the charging port of anything connected, like a smartphone or tablet. When a power bank starts to feel more like a hand warmer than a tech accessory, it’s time to unplug it for good and buy a replacement.

Have you ever loaded up a power bank, thrown it in your weekend travel bag, and pulled it out to find it completely dead? Noticeable drops in battery capacity like this are another big indicator that your battery bank has one foot in the grave. A healthy battery should hold a charge for at least a month when not in active use and should evenly distribute its stored power. Unfortunately, when a lithium-ion battery reaches the end of its useful life, its capacity gradually decreases. And while you might be tempted to save yours for emergencies, thinking it might offer you a quick 5% boost in a pinch, that’s just not a safe idea.

The problem here is that a battery with fluctuating voltage issues can create power surges and affect any gadgets you have connected to charge, potentially frying their delicate internal components. Additionally, a battery that continually struggles to hold its charge may overheat if you leave it plugged into an outlet in a desperate attempt to force it to 100%.

Once power delivery becomes this sketchy, the battery has crossed the line from a slight inconvenience to a real liability for your expensive electronics and your safety. It is better to abandon it and buy a new one. There are even power banks that do more than just charge.

People can be pretty casual in how they treat their technology on a daily basis, and that includes portable chargers. Power banks are thrown into heavy backpacks, dumped on sidewalks, and abandoned in cars during hot days and freezing nights.

Although quality manufacturers often use sturdy cases designed to withstand a variety of adventures, a big fall onto concrete can still cause serious damage to delicate components. And if a power bank has large cracks in its plastic casing or severely dented corners, it is statistically no longer safe to use. It is important to visually inspect your external batteries from time to time.

Relying on your sense of smell is also important. If you smell burning or chemical smells coming from your power bank, that’s a huge red flag. This may be the internal electrolyte fluid leaking from a ruptured cell. This liquid is incredibly flammable and toxic, even when the device is just sitting there and appears to be undamaged. Don’t let the stubborn desire to squeeze extra value from a cracked device lead to property or personal damage. If your power bank looks like it barely survived a war or smells like a science experiment, it’s unfortunately ruined.