Your LG G4 has a removable battery, and this kit helps you make the most of it.
Say what you want about Quick Charge or wireless charging, for many power users and frequent travelers, nothing beats the instant 100-percent refill delivered by a removable battery. The LG G4 is one of the few high-end phones still offering this feature, and to fully take advantage of it you'll want LG's extra battery kit.
The purpose of this kit is simple: You'll get an extra battery for your G4, and an external charger to juice up whichever battery isn't in your phone. In the U.S., LG is offering the extra battery kit as part of a promotion. And soon after launch it'll be available from top retailers like ShopAndroid.com
While older LG chargers came with a spring-loaded battery slot and could double as a cradle for the phone, the model for the G4 adopts a more Samsung-like approach. The charger itself (BC-4800) seals the unit in place with a hinged door, meaning it also doubles as a carry case for your spare battery. Up top there's a microUSB port, and an LED to show you when it's done charging.
The charger juices up the G4's battery (BL-51YF) at a lower voltage of 4.4V/1.5A, likely to avoid any unnecessary wear on the battery. That means it charges more slowly than it would in your G4 — the bundled charger supplies 5V/1.8A, and the phone also supports higher voltages through Qualcomm QuickCharge. But it's unlikely you'll be in a hurry to recharge your spare battery, so the lower output of the external charger makes sense.
The G4's extra battery kit isn't as flashy an accessory as a leather back, but it might just be the most useful investment a G4 owner can make. After all, if you've always got a spare battery ready to go, you'll never need to worry about being tied to a power outlet.