The increasing portability of devices has genuinely revolutionised how we use technology; where once to do anything IT related you’d have to sit at a desk and keyboard, these days you’re far more likely to whip the tiny portable computer – most of us call them smartphones – out of your pocket and purse to check emails, pay for groceries or just while away a few lazy minutes with a simple mobile game.
That’s great… right up until your battery starts to go flat. That’s when you need some kind of portable charger or powerbank to keep your device going for at least as long as it’s likely to take you to reach a power socket.
There’s no shortage of portable power bank options open to you at a wide array of price points, but buying the right portable charger for the job will ensure that you’re actually able to charge up sufficiently on the go rather than left frustrated and flat.
Battery capacity: Get what you need
Battery capacity for portable chargers is typically expressed in mAh, or millampere-hours. It’s (very broadly speaking) a measure of how much power a given battery (or battery cell) can output.
The smallest portable chargers ship with very small batteries, typically 2,000mAh or less. The largest can pack 20,000 or more.
So, which do you need? It’s a matter of matching up your needs and the specifics of your devices. Let’s say, for example, that you wanted a power pack to bolster the battery in an iPhone 15 Pro.
That’s a phone with a 3,274mAh battery, so a 2,000mAh battery pack would fill roughly 60% of its battery back in theory. It would be actually less, because power transfer even over a cable does involve some inefficiencies. Still, a small, cheap power pack might be enough if all you want is a a once-in-a-while boost to last you an hour or so until you get home or to the office. Smaller power pack capacity also equals lower weight, so they’re far more portable.
If you’re travelling further afield, or if you want to charge multiple devices, however, a portable charger with a higher capacity will be a better bet. A 10,000mAh portable power bank for example could (again, in theory) fully charge that same iPhone 15 Pro a tad over three times over before being exhausted. Start out the day with a fully charged phone, and you could last four days or more without ever having to see a power socket at all.
A tip for flying internationally
If you’re flying internationally, check with your airline as to the rules and regulations around portable power banks. Most are allowable on flights if they’re 10,000mAh or less, but you typically do have to put them in your carry-on luggage, not your checked luggage for safety reasons.
External connectors: Match to the right plug type
All portable power banks use USB connectors to charge, but there can be some variance in which sockets – or how many – they have. Simple and smaller chargers will typically have a single USB type A connector – the same rectangular type you find on many desktop and laptop PCs – that you can then connect a cable to, but some newer or higher priced chargers may offer multiple sockets or USB-C charging.
This is a matter of making sure that the cables you’re likely to use match up with the right ends on the power bank in question. You’re typically only likely to see USB-A and USB-C on most power banks, so it’s not too tricky to manage, though again if you do need to power up multiple gadgets a multi-socket power bank is your best bet.
Charging Ambitions: Beyond the smartphone
Most power banks will easily charge a smartphone over USB, but what if you need to power up a tablet or laptop on the go? It’s feasible, but not from every single portable charger. That’s because laptops and tablets (and other devices like portable games consoles) have higher power requirements, and the lower rate charge from a cheap power bank won’t meet those needs.
What you want to look for here is a power bank rated for USB Power Delivery, or USB PD. That certification means that it’s rated for specific, typically higher-level power draws; you’ll often find that power banks of this type specifically call out a few models they will work with, especially Apple MacBooks. Charging from a power bank will still generally be slower than from a wall socket, but it can be a great way to keep your laptop going under circumstances where it would otherwise just be a hefty silicon brick.
Wired vs. wireless
Some power banks will also offer wireless charging features. That’s convenient because – as long as your device supports wireless charging – you don’t need to pack cables as well, but it is notably slower and less efficient than cabled charging.
Don’t buy the cheapest power bank you find online!
There are countless power banks and portable chargers that can be bought online… but many of them simply aren’t worth buying. There’s a plethora of very cheaply made models sold online that don’t always match up with acceptable safety standards when it comes to battery charging and discharging.
Over time, that could turn them quite dangerous indeed if the battery cells within fail. The smart play here is to buy from a recognisable brand and reputable retailer, not just the cheapest you can find. The chemistry of the lithium batteries that most power banks use means that if they do experience thermal failure (mostly typically while charging), the results can quickly be catastrophic. Do you want to invite catastrophe into your home just to save a few bucks?
The answer there should always be an emphatic no.
