A guide to portable phone chargers

Whether you’ve been playing too much Candy Crush, or you’ve had to make a lot of business calls on a trip, sometimes your phone’s battery just isn’t good enough. Finding somewhere to plug in and keep your phone charged can be a massive challenge, especially when travelling or on a long day out and about. If you often face this problem, then a portable charger (or ‘power bank’) may be the solution.

Portable chargers provide the security of knowing you won’t lose phone access and the convenience of being able to use your device for longer without worrying about conserving battery. There’s a wide range of chargers on the market, with a wide price range to match. How do you sort through all of these and find the best charger for you?

Here’s what you should consider when deciding what kind of power bank to buy.

Size matters

Portable chargers are meant to be just that – portable. So it’s important to weigh up your power needs against the weight you’re prepared to add to your pocket or bag. If you’re just looking for something to help keep your phone topped up between access to power outlets, you probably only need something small and pocket-friendly. Conversely, if you’re working on the go with a tablet and phone to keep powered without reliable access to electrical outlets, it may be worth investing in something heavy-duty.

How much capacity do I need?

The charge storage capacity of batteries (including portable chargers) is measured in milliampere-hours, abbreviated to mAh. Essentially, the higher the number of mAh, the more power a battery can store.

Most products say on the packaging how many charges you can get out of the power bank, depending on the device being charged. You can figure out yourself what kind of capacity you need by looking at the battery capacity of your device or devices. For example, the iPhone 6 has a 1810 mAh battery. To figure out how many times your power bank will charge your iPhone 6, just divide the power bank’s storage capacity by the phone’s battery capacity.

Of course, it isn’t quite that simple. Storage capacity doesn’t necessarily correlate with how much of that power will reach your device’s battery. The performance of chargers varies depending on quality. It’s rare to get perfectly efficient charge storage and transfer. Poorer-quality brands with less efficient charging and discharging can mean as little as 70% of capacity is used, while better models hit close to 100%. You can guesstimate how many charges you can get out of a battery, but generally speaking you should keep your expectations lower than the on-paper performance. Checking out product reviews can be helpful.

Remember that if you’re using your device while charging, it will charge slower as you’re using up power that would otherwise be stored.

Cygnett ChargeUp

The Cygnett ChargeUp Sport has a capacity of 4,400 mAh and weighs 145g.

Why does amperage matter?

Not to be confused with mAh, the amperage (measured in amps, or A) indicates the speed at which electrical charge is transferred. A low amp connection takes longer to charge, and puts more strain on the charger. However, not all devices are capable of receiving high amp charges so it’s not necessarily helpful to go for the bigger amp output. More power-hungry devices tend to need a higher amperage charger to retain power efficiently. For example, tablets generally require minimum 2A to charge fast enough to get anywhere soon with recharging.

Most power banks come with one 1.0A USB output. Bigger power banks tend to come with two USB outputs – one rated at about 1.0-1.6A and another rated at 2.0A, or in some cases two 2.0A outputs. The 2.0A outputs will charge your phone, tablet, or other device much faster.

Can I charge my device while also charging my power bank?

If you’re really in a tight spot, you may find yourself with one power outlet and both a device and a power bank that need to be charged. Can you plug your portable charger into the wall, then plug your device into the portable charger and have both devices charging at the same time?

It depends. This is a feature called ‘charge-through’ or ‘simultaneous charging’. Not all portable chargers support this feature, and for those that do you should consider whether you’re getting the amperage to actually charge both at the same time. Essentially, your wall charger should be rated at a higher amperage than the power bank output you’re using to charge your device. This makes sure that the charge coming from the wall outlet is getting to both batteries.

Jackery giant+ image

The Jackery Giant+ carries 12,000mAh, has both 1.0A and 2.1 USB outputs, and weighs 295g.

Is it a good idea to buy online?

If you’re looking for a bargain, you might be drawn to eBay or other online shops to find a good deal. And at first, you’ll find thousands of power banks online that are much, much cheaper than the equivalents available in Australian stores. However, this is more often than not too good to be true. Like with any electronics purchase, you need to be wary of a few things.

Fake labelling is a massive problem with a lot of portable chargers sold online. The listing, packaging, and even power bank, itself may be labelled with a high capacity, but it’s only if you break open the case and look at the battery cells inside that you may find out that you’ve been ripped off. Your 10,000 mAh charger for $15 might actually just be a 1,800 mAh cell, which isn’t such an amazing deal.

Only buy from reputable, verified name-brand companies to ensure that you’ll get what you pay for. An eBay seller with high feedback doesn’t count!

Another consideration is laws about posting and importing batteries. This is again something that shouldn’t be a hassle if you buy from a reputable retailer – they should tell you if the battery cannot be posted to you before checkout.

How long will my portable battery last?

The battery inside portable chargers is almost always a lithium-ion polymer cell or cells. Generally speaking, there’s about 500 charge cycles in a lithium-ion cell before its capacity becomes diminished. If you’ve owned a phone for more than two years, you’ll have experienced this. As batteries age, charges start lasting less and less time for phones. When it comes to portable chargers, it starts to take longer and longer to charge up to full.

Another factor in how long your battery will last is construction quality. There’s a wide variance in the quality of lithium-ion cells. However, it’s difficult to tell what kind of cells are inside cases without tearing the charger apart. A useful way to get information about quality can be by reading professional and user reviews to find out what kind of performance to expect from the product.

Do I need a cable?

Don’t forget to consider cables! Many chargers come with a cable, but of course you can use a micro-USB cable you already own. It might be helpful to consider what cables you need to suit your needs. For example, it’s much more convenient to have a very short cable for pocket or bag charging, so you don’t have long cables needlessly getting in your way

So how do I choose?

When it comes to comparing the different products available, the following questions are important to decide which power bank best suits your needs.

  • Do I need something pocket-sized or can I easily carry something heavier in my bag?
  • How much battery storage capacity do I need?
  • Do I need a high-amperage output? Do I need more than one USB output?
  • Do I need ‘simultaneous charging’ functionality?
  • What’s my budget?

Once you’ve answered these questions, you can narrow down to a shortlist of portable chargers that fit your needs. Checking reviews from both professional reviewers and average users can help you decide which power bank to purchase, and from where.

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