As much as you try to conserve battery power on your Apple iPhone 5 the iPhone’s battery will surely start crying out for more juice before you get the chance to recharge it. See: What's the best battery case for iPhone 5.
Mophie and others tackle this problem of low battery power with a range of battery back ups for the iPhone 5 and other smartphones.
The most agile solution is the battery case – a protective case for the iPhone that includes a slim battery that you can switch over to when your iPhone starts dying on you.
The Mophie Juice Pack Plus is the iPhone 5 case with the largest battery charge: in technical terms, 2,100mAh compared to the Helium’s 1,500mAh and the Air’s 1,700mAh. In practical terms this translates, in Mophie’s claims, as an extra 120 percent charge for the Plus, 100 percent for the Air, and 80 percent for the Helium. See: iPhone 5 review
That means that the Plus should be able to charge a dead iPhone battery right back up to full power again, and then up to 25 percent when that had been used up before requiring a recharge itself. See: iPhone case reviews
Battery boost claims tested
With the Helium we found the claimed 80 percent recharge translated in real terms as closer to 70-75%. The Juice Pack Air’s claimed 100% was more like 95%, so pretty close for both battery packs.
With the Mophie Juice Pack Plus we certainly managed a full 100% recharge in real-world tests, but couldn’t get much more out of the battery case after that.
Mophie Juice Pack Plus design
The Plus is very like the Air in terms of design, with a top-quality feel and robust protective feel. It’s slightly larger than the Air but the same weight (76g).
When you first slip the iPhone into the Juice Pack case you’ll notice the extra bulk created by the battery, but after a day or two it just becomes natural to you. Yes, you’ve bulked up a super-slim smartphone, but that mobile will now last a couple of days between charges.
There are cutouts for the camera and the same covered button overlays for the Sleep/Wake, Ring/Silent and Volume buttons that we liked on the Air.
There’s one caveat we’d add when comparing the Air and the Plus battery cases. While the button overlays worked perfectly on the Air we found the volume switch on the Plus was not as easy a fit as it is with the Air. That's why we've scored the Mophie Juice Pack Air higher in terms of build quality.
Like all battery cases for the iPhone 5 users with an angled headphone jack will need to use the supplied pass-through headphone extension. Most headphones, however, work fine with these cases.
The Mophie Juice Pack Plus is available in black, red and white colours, at a price of £109.95.
(The Juice Pack Helium costs £69.96, and the Juice Pack Air £89.95.)
Mophie also makes a Juice Pack battery case for the Samsung Galaxy S4.