Mophie says the Juice Pack Reserve is the most compact battery case it's ever created, adding just 0.3 inches of thickness and 75 grams of weight to the iPhone 6 or 6s. In my testing, I found that Mophie's claim that the case is in a form factor that "you'll barely notice" is mostly true, although with a caveat. Its soft-touch back provided a comfortable and easy-to-grasp grip despite feeling noticeably more dense. However, the case's lower lip, where the speaker grille resides and the case plugs into the iPhone, is far more noticeable and users not accustomed to the extra length will have to spend some time acclimating to it when scrolling or typing.
The case's extra mass was not a hindrance when attemtping to quickly capture moments at the wedding though, as it slipped in and out of tuxedo pockets fairly easily. In fact, the in-pocket feel of the case was barely noticeable in tuxedo pants, even during more intensive activites like dancing. The extra mass of the case is, however, more obvious visually. In more regular daily use, the case was even less of a hindrance.
Mophie claims the Juice Pack Reserve will provide an additional 60 percent charge to an iPhone 6 or 6s, with the latter carrying a 1,840 mAh battery. This claim was actually conservative in my testing, with an iPhone 6, as I was able to consistently get a full charge from the case. For example, I was able to go from 10 percent to 100 perfect battery in just about two hours and six minutes and then 4 percent to 93 percent in about the same time.
The back of the Juice Pack Reserve features four LEDs that indicate the case's battery level next to a small button. When you hold this button down for a couple of seconds, it turns on the case and begins to charge the phone. The case was also able to easily get me through a full 14-hour day of battery-intensive Facebooking, Snapchatting, video recording, and photo taking while using the battery pack on and off during the wedding.
The rest of the case functioned without much trouble. The pass-through volume and power buttons are easy to use and reliable, the speaker holes generated no noticeable dip in audio quality, and the slot for the headphone jack was not an impediment. However, the cutout for the mute switch did make access a bit more difficult than without the case. The pass-through microUSB charger for the case's battery also worked well, intelligently sensing when it needed to charge the case versus the phone.
The smaller and more compact Power Reserve 1X, which houses a 2,600mAh battery in its soft-touch case, comes with both a single USB and a microUSB port. The microUSB port is for charging the battery pack while the USB port is to charge smartphones and wearables. Of course, users will have to provide their own charging cables.
Like its larger cousin, the Power Reserve was able to provide a full charge to my iPhone 6 in about two hours. It too has four LEDs indicating its power level next to a small button. With its larger battery capacity compared to the Juice Pack Reserve, the Power Reserve was able to provide a total of one and a half full charges to an iPhone 6. Additionally, the small button on the Power Reserve is only used to view the battery pack's power level, as devices plugged into it automatically start charging.
Mophie says the Power Reserve uses "Charge Vault" technology and digital power management to hold its charge while also intelligently detecting the device its plugged into to adjust charging speed accordingly. In my testing, these claims appear to be true. I did not use the device for a week and then came back to it, pressed the power indicator button and found that it still had a full charge.
Carrying around the Power Reserve is a fairly easy endeavor, as the actual battery pack easily slips into pockets and it's equally easy to forget about. However, having to carry around a USB charging cable for your device makes the entire thing a little less practical. It is worth noting, however, that at the wedding I was able to easily share a charge with several other iPhone users who needed it.
Mophie says the Power Reserve 1X also works for wearables, in my case an Apple Watch, but in practice it feels a little silly. Not only do you have to take off your wearable to charge it, but you have to carry around the Apple Watch's charging cable, which is highly impractical and unwieldy, particularly if you're using the 2-meter cable that comes with the watch. If you need this device to charge your Apple Watch on the go, it would be wise to find a shorter charging cable.
Both the Power Reserve and Juice Pack Reserve did experience rare hiccups when testing, although for the most part they didn't significantly impact overall usability. For instance, in one case my iPhone battery displayed a 10 percent charge while being charged by the Juice Pack, but when the charge case was turned off the phone switched to 1 percent.
The Juice Pack Reserve is a good recommendation for those who want the convenience of a battery case without too much of the extra mass. It's also a very good option for when you need extra power during special events, like a wedding or reunion or even a vacation. The smaller Power Reserve is a little more difficult to recommend, however. While it works well and is largely convenient to carry around for iPhone users who need to share charges in a group environment, there are cheaper alternatives on the market that provide more charge than it can.
Both the Juice Pack Reserve and Power Reserve 1X are available in white, black, purple, blue, and pink and are available on Mophie's website.