iOS Device backup battery review two-pack: Mophie Juice Pack Plus for iPhone 5, Just Mobile Gum Max Duo

  • joko
  • October 24, 2016
  • Comments Off on iOS Device backup battery review two-pack: Mophie Juice Pack Plus for iPhone 5, Just Mobile Gum Max Duo

For the past few weeks, we have been testing two battery backup accessories for iOS devices: Mophie’s Juice Pack Plus case for the iPhone 5 and Just Mobile’s Gum Max Duo accessory for iPads, iPhones, and iPod touches. You can find our full reviews of both battery accessories below:

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Mophie Juice Pack Plus for iPhone 5:

Following the release of both the Juice Pack Helium and Juice Pack Air for iPhone 5 (which both received positive reviews in our March comparison), Mophie has released an additional “Plus” model of the iPhone 5 backup battery case. While the Helium focuses on being thin and light and the Air focuses on thin/light plus battery capacity, this new Plus model is all about battery power and ruggedness. It is the top of the line iPhone 5 battery pack from Mophie.

Like its less-powerful siblings, the Plus model includes two pieces for the case: a large part that holds most of your iPhone 5 and the actual battery and a second, small piece that connects the battery to your iPhone via a Lightning port. This bottom piece also allows you to charge both your iPhone 5 and the Plus case via a USB port. Like the other models, this design allows access to all hardware volume controls, sleep/wake controls, camera + LED flash, and the bottom earphone jack.

The bottom piece also includes speaker holes which slightly amplify sound. However, if you’re looking to purchase this case, it should be for the extra juice, not the extra sound. Those looking for more sound should check out some external speaker systems. Additionally, this piece includes the standard Mophie battery juice reader for the external pack. This button is akin to battery meters Apple included on its older notebooks: it’s an easy four light system for checking how much juice is left in your case. It also has a power switch for conserving power when your iPhone’s built-in-battery is full.


In terms of design differences, the Plus matches the Air in color options, but does not offer the dark and light silver metallics that the Helium ships in. Because of the bigger battery, the Plus case is less svelte than the Air and Helium, coming in at 0.7 inches thick (versus 0.59 inches for the Helium and 0.63 inches for the Air). I don’t believe this to be a huge trade-off in design for the extra juice that the Plus offers. However, if you’re into making your iPhone 5’s battery case as thin and light as possible, the Helium is your best bet.

In addition, the Plus offers a rugged texture along the sides of the exterior. This can help protect the case and even your iPhone 5 as the rugged texture could deflect some damage from drops, knocks, and the like.

The slightly extra thickness and weight of the Plus model yields a battery case with 2100 mAh of battery capacity. That extra .07 inches over the Air and . 11 inches over the Helium means an extra 400 mAh and 600 mAh of juice for the Plus, respectively. For an iPhone 5 in the Plus case, this means an additional 10 hours of 3G talk time, 10 hours of internet over 3G/LTE (12 hours on WiFi), 50 hours of music, and 12 hours of video playback. For anyone who has used an iPhone 5 without a backup battery, those numbers are a dream.

Here’s how the three cases compare (Plus, Air, and Helium – in order):

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In our tests, the Plus seems to live up Mophie’s expectations for battery juice. Additionally, we have found that the case does an excellent job of retaining battery over time (when it is not in use). This is similar to Apple’s MacBooks retaining battery life while they are in sleep mode for several weeks. You can leave the case fully charged in a drawer for a few weeks, come back, and have a lot of battery life to spare without the need to re-charge.

We highly recommend Mophie’s Juice Pack Plus for anyone looking for the best combination of intense battery life capacity, cool, slim design, and price. For example, the Plus model is $30 higher than the Air, yet delivers substantially better battery life improvements for your iPhone 5.

Just Mobile Gum Max Duo:


On the other end of the battery accessory spectrum is Just Mobile’s Gum Max Duo accessory. This one is not a case, yet it’s an external battery pack with two USB ports. It’s built up to charge iOS devices like the iPhone, iPad, and iPod touch, so it’s more functional than a single-purpose iPhone battery case. However, the trade off is a sized-device that you can’t keep connected to your iOS device in your pocket (for example).

After using the Gum Max Duo for several weeks between multiple flights and trips, one of the most impressive things about this accessory is its battery capacity. I have charged up iPhone 5s and iPad minis a couple times each, and I still have some battery life to spare. This is thanks to an impressive battery capacity of 11200 mAh, which is nearly double the 6000 mAh found in the external Mophie Duo that we reviewed earlier this year.


The Gum Max Duo charges itself over micro-USB, and as the name implies, can charge two devices via full USB ports. The product itself is about the size of a standard’s men’s wallet, which is impressive for the amount of juice that the device can hold. The two USB ports differ in outputs, so the 1A port is optimized for the iPhone while the 2.4A port is perfect for the newer full-sized iPads that feature large internal batteries. We mostly used this accessory with iPhones and the low-power-intensive iPad mini, but Just Mobile claims an extra 7 hours of full-sized iPad juice with the accessory.


The case’s aluminum design is durable and nice to look at, and Just Mobile ships multiple rubber covers for the accessory in some fun colors. We like the Gum Max without a colorful wrapping, however. The only button on the top of the accessory is one to check the battery meter.

We highly recommend this Gum Max Duo for anyone looking for a combination of high-battery capacity and great design for a fair price. The accessory currently runs for a little over $100 on Amazon.