Hands on: Aukey PB-T11 30000mAh Power Bank review

One thing that hasn't improved a lot over the last decade in technology is battery capacity. The trend towards cramming more into ever-thinner chassis sizes has forced designers and engineers to aim for new sweet spots in terms of dimensions and weight.

Witness the rise of smartphones with larger than 5-inch displays and ultrathin laptops with 13-inch or bigger screens.

Couple that with components which demand more power and it is not surprising that emergency portable chargers, or power banks as they are commonly known, have grown so much in popularity that they are even given away.

Now an essential part of the gadget assortment of every businessperson, the power bank is becoming more complex and, like the mobile phone, is gradually adding more capabilities to its feature list.

Aukey sent us a 30,000mAh power bank, the PB-T11, for a quick test drive and while the product is not currently available in the UK, it's only a matter of time as the 20000mAh model is on Amazon for £27.99 (around $35, AU$50). This product is so new that Aukey's website still hasn't listed it, and it's currently on sale in the US for $49.99 (around £38, AU$65).

The portable charger is surprisingly small at 150 x 82 x 28mm but weighs more than we were expecting (552g), which makes it rather hefty/dense. It's made entirely of plastic which makes sense to save costs and also because that material is unlikely to damage other more expensive devices when lumped together in a rucksack.

The device is shaped in a way that allows you to hold it comfortably with one hand, and is just small enough that you can slip it into the interior pocket of your jacket or your jean's back pocket if you have a large one.

The Aukey power bank came with one leaflet and a short USB Type-C cable; there are no other cables or power adaptors.

The device comes with a full two-year warranty although it is unlikely to cover the gradual drop in capacity that affects all batteries (remember that they're powered by chemicals and as such degrade over time).

You can charge it via Lightning or microUSB – or charge faster by using both at the same time. Sadly, there's no option to charge via USB Type-C, which is odd given that the bundled cable is USB-C. The only output connectors available are two full-sized USB Type-A connectors, one orange and one green.

The first one is a Quick Charge 3.0 port which offers a wide range of voltage and amperage: 3.6V-6.5V/3A, 6.5V-9V/2A, 9V-12V/1.5A in steps of 0.2V; that allows devices to be refuelled faster – up to four times faster according to Qualcomm – without running the risk of frying any components.

This technology, by Qualcomm, requires a compatible device in order to work correctly – that means using a smartphone powered by a mainstream or high-end Qualcomm processor in most cases. A QC 3.0 device will charge to 50% in about 30 minutes.

The second connector is rated at 5V/2.4A, which is pretty much the standard for standalone chargers. Both ports support Aukey's proprietary battery technologies (AiPower Adaptive Charging Technology and Aukey EntireProtect) which aim to charge devices faster and more safely.

There's a nifty little white LED which can be switched on by long-pressing the power button. The latter turns to red to indicate a battery level below 30%, green for anything between that and 70%, and white for anything above 70%.

Note that the PB-T11 will automatically turn off after 15 seconds. Just bear in mind that this is a 30Ah brick which means that even under ideal charging conditions, you can expect it to take a long time to reach full capacity.

Expect it to take at least 12 hours using one port and about half that if you use both the microUSB and the Lightning port.

In the world of batteries, never take numbers as absolute truth. They're more often than not just a rough indication of what capacity a device can offer in optimum, out-of-the-box situations.

And this usually gets worse pretty much immediately as the potency of the chemicals starts to fade. So don't expect a rechargeable battery to offer the same capacity after a couple of hundred charge/discharge cycles.

From full (after leaving it for 15 hours to charge from the mains using a 12W charger), we were able to use this unit to fully charge the Chuwi Hi12 twice (11Ah battery) and the Jumper EZpad 5S once (8.5Ah) before the power pack ran out of juice.

Bear in mind that the actual battery capacity of these two tablets is likely to be less and they were not totally flat before charging (both were showing single digit battery percentages on Windows). So it's not exactly 30,000mAh, but it comes pretty close.

Early verdict

Choosing power banks and portable chargers can be a bit of a minefield and the safest way to go about it is to buy from better known brands – if you're not sure, check Amazon's bestseller list to get an idea of the main players out there.

For roving business people power banks are a godsend and the higher the capacity the better. This one is no exception – it's light for its capacity, surprisingly compact and, based on US prices, relatively cheap as well.

We'd prefer to have an integrated cable (for times of emergency) and a USB Type-C connector, though with the ability to automatically start delivering power when connected. We would also have liked a faster way of charging the device itself.

And while this device can charge most 2-in-1 convertibles (the tablet ones with detachable keyboards), you won't be able to charge laptops (except for the new MacBook that is).

• Check out our round-up of the best portable chargers