Phones keep getting bigger and better, but battery life remains largely the same. The aptly named $129.99 LG X Power is a step in a different direction. It packs a positively massive 4,100mAh battery into a slim and lightweight build, while offering solid performance and a 5.3-inch 720p display. It has a hefty UI layer and its camera isn't the best, but if a long-lasting phone is what you want, the X Power can easily keep you running for more than a day. It's a good affordable phablet for Boost Mobile power users.

Design, Features, and Display
The X Power isn't going to win any beauty contests. It's a simple black polycarbonate slab that only stands out because of how thin and light it is in relation to its large display. Measuring 5.9 by 3.0 by 0.3 inches (HWD) and weighing 4.9 ounces, it's just as thin as the Samsung Galaxy J7 (6.0 by 3.0 by 0.3 inches) and more than an ounce lighter (6 ounces). It's also significantly smaller than the LG Stylo 2 (6.1 by 3.1 by 0.3 inches, 5.1 ounces), which itself has a sizable 3,000mAh battery under the hood.

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There's a micro USB charging port and audio jack on the bottom, and a power button on the right. The volume rocker is on the left, with a combined SIM/microSD card tray that works with a 256GB Samsung Evo+ card.

Somewhat uncharacteristically for LG, the back of the phone is sealed shut and the battery is nonremovable. But it makes sense when you consider the size of the cell—a whopping 4,100mAh—and the relatively slim build. LG likely optimized every millimeter of space in order to fit it in.

The front is home to a crisp 5.3-inch, 1,280-by-720 IPS LCD. It works out to 277 pixels per inch, which is a bit sharper than the larger display on the Stylo 2 (258ppi) and the ZTE Warp 7 (267ppi). Viewing angles are good and there's no noticeable pixelation to text or icons, but brightness is somewhat lacking. Even when set to maximum, the screen isn't visible enough to use in direct sunlight. The Galaxy J7's AMOLED display is a much brighter and richer panel.

Network Performance and Connectivity
The X Power runs on Boost Mobile, which is part of Sprint, so you'll find identical service across the two carriers. It supports LTE bands 2/4/5/12/25/26/41, giving it decent connectivity in midtown Manhattan where I saw speeds similar to other Boost Mobile and Sprint phones we've tested in the same area. Like the Warp 7, the X Power also supports international roaming in Mexico. However, it doesn't have NFC or dual-band Wi-Fi, which isn't too surprising givn the price. For those features, you'll need the more costly J7.

Call quality is good. Transmissions are clear and have natural tones, and earpiece volume is loud enough to be heard over a noisy environment. Noise cancellation can lend a slight robotic edge to voices on outgoing calls, but it's not drastic.

Processor, Battery, and Camera
The X Power has an octa-core MediaTek MT6755M processor clocked at 1.3GHz. On the AnTuTu benchmark, which measures overall system performance, it scores 43,023, nearly double the scores of the Qualcomm Snapdragon 410-powered Warp 7 (26,882) and Stylo 2 (26,822). It also scores significantly higher than the Snapdragon 617-powered J7 (33,107).

Real-world performance good. The phone handles multitasking well, and doesn't suffer from serious slowdowns when using resource-heavy apps. That said, the phone does only have 2GB of RAM, so it's possible to hit the usage limit if you push it too hard, at which point you'll notice some stuttering. Playing high-end games like GTA: San Andreas is possible, but you're likely to experience the occasional dropped frame or sluggish controls.

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Battery life, as mentioned, is excellent. The LG X Power lasted for 8 hours and 48 minutes in our grueling battery rundown test, in which we stream full-screen video over LTE at maximum brightness. It's one of the longest results we've seen on an affordable phone. It just about matches the top-of-the-line Samsung Galaxy S7 (9 hours), and significantly surpasses both the Warp 7 (5 hours, 49 minutes) and the Stylo 2 (6 hours, 6 minutes). This is definitely a good phone for anyone who usually finds their battery needs a recharge by lunchtime. The phone supports fast charging with the included adapter, but because of the capacious battery, it still takes about two hours to reach a full charge.

Camera performance, on the other hand, is nothing to write home about. The 8-megapixel rear sensor is mediocre, even in good lighting conditions. Trees, bushes, people in motion, and areas of fine detail ended up blurry, noisy, or simply out of focus. I was only able to take some good shots, but only after manually focusing the camera and allowing ample time to set up the shot. Video records in 1080p at 30fps, but it has the same issues with focus and noise, while low-light pictures suffer from grain. The 5-megapixel front-facing camera, meanwhile, takes clear and well-focused shots outdoors, though it can be somewhat muddy in lower light.

Software
The X Power runs Android 6.0.1 Marshmallow, with LG's fairly extensive UI layer running on top. The app drawer has been removed, which is frustrating. Instead, apps are splashed across the home screens, similar to the Apple iPhone 7.

Bloatware is also heavy. There are 16 pre-loaded Boost apps, 5 Amazon apps, LG SmartWorld, Facebook, Instagram, Messenger, and Uber. Most of the Boost apps can be uninstalled, but the rest can only be disabled. There's even an Uninstalled apps app that shows you your recently uninstalled apps and lets you reinstall them if they've been removed in the past 24 hours. That app cannot be uninstalled, amusingly.

You're left with 10.03GB out of a total of 16GB of storage. You can add a microSD card, but Marshmallow's Adoptable Storage feature that allows the card to be formatted as internal memory is disabled, so you can only use it to save pictures and video.

Conclusions
For the price, the LG X Power is a capable phone for Boost Mobile users that can keep you browsing, texting, and talking for hours longer than most comparable devices. The Samsung Galaxy J7 gets you a brighter AMOLED display, a sharper camera, and features like NFC and dual-band Wi-Fi, but it'll cost you $70 more. The LG Stylo 2 is more affordable and has some useful stylus-optimized features, but it's held back by an aging processor. The Warp 7 is a strong rival, thanks to its lower price and nicer build. But if you're tired of worrying about your phone dying and don't want to carry around a backup battery, the X Power is a solid option.