If this Choetech power bank looks familiar then that's because it should be - it's the bigger brother of the B611Q, rated at 15600mAh, which I reviewed about six months ago. In fact. the casing seems to be identical, with just a higher number of Li-Ion cells inside, adding around 15g in weight and around 4600mAh in capacity. In all other aspects, the B613Q is essentially identical. However, it was sent in for review and does join the elite group of power banks that break the 20000mAh capacity threshold without being stupidly large (here's the other one I've reviewed).

Plain packaging for a rather plain power bank, but this is all about function over form, so no worries on that score...

Showing the tech specs of the four inputs/outputs. One Quick Charge 2.0 input (microUSB) and one Quick Charge 2.0 output (USB Type A)...

Much of the text from the review of the B611Q applies here. From my conclusion:

In summary, I liked the solidity of the accessory, the price is very reasonable, the dual (i.e. in and out) Quick Charge 2.0 facility is unusual but welcome (I'm sure we'll see other chargers this year appear with the technology) and the Lightning input option... quirky. Though, living in a house of iPhone owners, maybe even I'll get to need this one day, in an emergency!

The B613Q is really.... solid. A massive capacity that will keep most families going for a weekend, or a single person for a week's road trip, dual (fast) charging for both input and output, and a no-frills black plastic obelisk design. However, I can't help but feel that something's missing...

And that something is USB Type C, which has been appearing in smartphones for six months now and will be almost the default by the end of 2016. The switch from microUSB to USB Type C in the industry has been a long time coming, but the advantages in terms of ease of use, robustness and bi-directional power handling just can't be ignored. Both the new Lumia flagships support fast charging via USB Type C (even if Quick Charge 2.0 support seems debatable at this point) and we've seen USB Type C in the 2015 Macbook, the Nexus 5X, 6P, the OnePlus 2, and so on. So why not add an extra jack to this design? A USB Type C in/out port would be a really useful and future proofing feature. And would make the Choetech power banks a real jack of all trades.

Maybe for the new 2016 models, which should be available later in the year? In the meantime, the B613Q is a very solid choice if you need high capacity, Quick Charge 2.0 topping up of the power bank tself, and Quick Charge 2.0 output for at least one device.

You can find it here on Amazon UK and at other good outlets online.