Don’t worry: Portable cellphone battery chargers are not likely to explode

Q: How safe are portable power banks used to charge a cellphone or tablet?

With all the exploding battery stories surrounding the Samsung Galaxy Note 7, there seems to be a heightened awareness of battery issues, which is actually a good thing.

Lithium ion batteries are in just about every rechargeable device we own and there have been many instances of them catching on fire in everything from laptops to hoverboards to Tesla cars and even Boeing’s 787 Dreamliner.

In fact, there have been over 40 recalls by the Consumer Product Safety Commission since 2002 for products with defective lithium ion batteries.

Despite all of the stories of exploding batteries, it’s actually quite rare when you take into consideration the number of devices we all have with lithium ion batteries.

Why batteries catch fire

The very nature of how they work is also what subjects them to becoming a fire hazard.

There is a potential for a “thermal runaway” chain reaction whenever the battery becomes overheated, so keeping any device as cool as possible is important.

Well-made batteries have safety features built into the battery itself to prevent overcharging and overheating, which is why exploding batteries are relatively rare.

Common mistakes

The biggest mistake that most people make when using or charging a device with a lithium ion battery is contributing to the overheating.

For example, using a laptop for extended periods on a soft surface, such as a pillow or comforter, usually blocks off any air vents and acts like an insulator, which keeps the heat from dissipating.

This scenario can be even more hazardous if you’re charging the laptop at the same time, as charging always generates additional heat.

If your device has been exposed to direct sunlight and is hot to the touch, you should wait until it reaches room temperature before attempting to recharge it.

Using the wrong charger to recharge your battery is another major contributor to problems, especially when too much energy is passed during the charging process.

If you ever lose your charger, it’s always safest to replace it with the original manufacturers replacement instead of a third-party charger.

Portable chargers

To date, I’m not aware of any portable chargers that have been recalled because of a battery defect, but knowing that the design of the unit is a critical factor, I’d suggest you stick to name brand chargers.

I’ve always been a fan of the products from Mophie, Anker and IOGear.

Choosing a charger

A portable battery’s capacity is rated in milliamps hours or mAh and amperage (A) with the higher the numbers, the more capacity it has to charge your devices.

Generally speaking, the higher the capacity, the larger the battery as well, so finding the right combination of size and capacity is key.

Start by determining the battery capacity of the item(s) you want to charge and then divide the capacity of the portable charger by that number to determine how many charges you can expect.

If you plan on charging larger devices, like a tablet, you’ll also need to make sure the amperage is high enough to get the job done (usually 2A).