Some people carry around tiny external batteries, usually only for partially charging a dead phone. Others prefer a slightly larger unit, to recharge phones or tablets once or twice over. But if you're planning to go without power for a few days, and you need to charge all the things, Anker's giant 120,000mAh battery has you covered. Now you can get it for $329 on Amazon, $170 off the usual price of $499.
The PowerHouse is equipped with a 12V car socket, a 110V AC outlet for devices up to 120W, and 4 USB ports. It also has a handy LED indicator at the top, showing the remaining capacity and other info. You probably won't be able to take this on an airplane for PC gaming at cruising altitude, but it would be great for long-term power outages or camping trips.
If you've been wanting to grab this behemoth, you can do so at the link below. It's sold by AnkerDirect, not by Amazon, so there is no Prime shipping available.