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’s battery dips into the red zone. Thank goodness you have your trusty power bank with you, as it’s an absolute lifesaver in situations like these. But while we tend to think of these portable chargers like invincible bricks of endless energy, whether they’re the best wireless power banks or corded, the reality is that they actually have a finite lifespan and should be handled with care, otherwise they can get damaged and become unsafe to use. In fact, if your power bank looks swollen, gets super hot, dies quickly, or is damaged somehow, it isn’t safe to continue using.

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

However, a dying power bank will often have physical and functional warning signs that it’s failing. If you want to protect your tech 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.

Hands down the easiest issue to spot is a power bank case that’s swollen; in fact, that goes for any battery-powered device, like your phone or laptop. If your power bank can no longer sit perfectly flat on a table, or if the casing looks like it’s expanded or cracked open along the seams, you should stop using it right away. Do not plug it into an outlet, and definitely 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 break down over time, usually from overcharging, extreme temperatures one way or the other, or simply old age.

This pressure buildup causes swelling, which will eventually push outward at the bank’s casing, and that’ll only hold up for so long. If it’s punctured or subjected to any more stress, a swollen battery like this can easily catch fire or explode. For the record, there’s no way to save a battery in this state; it’s a lost cause. If you’ve noticed a slight curve to your previously-flat power bank, it’s become an active hazard.

When you have a lithium-ion battery you no longer need, especially if it’s damaged or swollen, the Environment Protection Agency states that “these batteries should not go in household garbage or recycling bins.” And that, to properly dispose of them, they “should be taken to separate recycling or household hazardous waste collection points” that the agency recommends on its website.

It’s perfectly normal for a power bank to get slightly warm while either charging devices or being recharged from a wall outlet. Moving electrical current naturally generates a little heat, especially for fast charging. However, there’s a big difference between this gentle, expected warmth and a device that gets uncomfortably hot to the touch. If a battery bank gets so hot that you hesitate to hold it, or if it feels like it’ll burn other materials, something is definitely wrong internally.

This extra heat often means the battery’s internal resistance has skyrocketed. High-quality power banks typically rock built-in thermal sensors that’ll shut them down if temperatures get too hot. That’s one of the concerns over why power banks keep catching fire on planes. If your charger is getting scorching hot, that means those crucial safety mechanisms either failed or never existed.

Continuing to use an overheating power bank is a bad idea, speeding up any internal problems it already has or creating new issues. Intense heat like this also travels through the charging cable, which can permanently damage the charging port on anything connected, like a smartphone or tablet. When a power bank starts feeling more like a hand warmer than a tech accessory, it’s time to unplug it permanently and buy a replacement.

Have you ever charged a power bank, tossed it in your travel bag for the weekend, 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 one month when not in active use, and should dole out its stored power evenly. Unfortunately, when a lithium-ion battery reaches the end of its usable life, its capacity fades gradually. And although you might be tempted to keep yours around in case of emergency, thinking it could offer you a quick 5% boost in a pinch, it’s just not a safe idea.

The issue here is that a battery with fluctuating voltage issues can create power surges and affect any gadgets you’ve connected to charge, potentially frying their delicate internals. What’s more, a battery continually struggling to hold a charge can overheat if you leave it plugged into an outlet in a desperate attempt to force it up to 100%.

Once power delivery gets that sketchy, the battery has crossed the line from a mild inconvenience to a genuine liability for your pricey electronics and safety. It’s best to just ditch it and get a new one. There are even power banks that do more than just charging.

People can get pretty casual with how they treat their tech on a daily basis, and that includes portable chargers. Power banks get tossed into heavy backpacks, dropped onto sidewalks, and left rattling around in cars during hot days and freezing nights.

While quality manufacturers often use rugged shells designed to hold up during various adventures, a big drop on concrete can still do serious damage to the delicate components. And if a power bank gets big cracks in its plastic housing or has severely dented corners, it’s statistically no longer safe to use. It’s important to visually inspect your power banks every now and then.

Relying on your sense of smell is also important. If you smell a burning or otherwise chemical odor wafting from your power bank, that’s a massive red flag. That’s possibly the internal electrolyte fluid leaking from a ruptured cell. This fluid is incredibly flammable and toxic, even when the device is just sitting there and otherwise looks fine. Don’t let a stubborn desire to squeeze extra value out of 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 done for.