Portable batteries have become more stylish, cheaper, smaller, and faster at charging your tech. More improvements are on the way, thanks to gallium nitride (GaN), a more space- and energy-efficient alternative to silicon that can already be found in a few wall chargers. Nice as these advancements are, they mostly impact devices with small batteries. Wall chargers aren’t much help if you’re on the go. As more laptops and other high-powered devices adopt USB-C and move away from proprietary charging plugs, there’s an opportunity for big, powerful batteries that can augment your power adapters, and ideally, let you charge multiple devices at the same time. And now, a number of options are hitting the market aimed squarely at doing just that. We have tested a few models that are available now, as well as some that are coming out soon. The list includes Zendure’s SuperTank, Sanho’s HyperJuice, and J-Go Tech’s Tanker Elite and Tanker Xtreme. They all have a few things in common: they aren’t small or lightweight, so your bag will gain more than a few ounces if you stick one inside. Each of these batteries has USB-C Power Delivery ports capable of delivering at least 65W of power (and ...