This all important item? A high-powered, portable battery charger. There are three important features I looked for before buying one:
1. Multi-use compatibility: There are lots of portable chargers for individual devices. For example, portable HTC One Chargers and iPad chargers. But I'm not brand loyal, so I needed something that could quickly and effectively charge a tablet, phone and even a GoPro camera.
2. Charge capacity: Again, there are plenty of chargers on the market capable of restoring battery life once or twice, but on a roadtrip where access to outlets is limited, it's important to get more power than that. Anything with 10,000mAh of capacity or above should charge an iPhone at least four to five times, an Android phone three to four times and a tablet at least once.
3. Fast and accurate charge: It's not uncommon for a car charger to show it's charging a device quickly only to find out the true battery power is about 30% to 40% less than reported. Accuracy is key when on the road, because I have to decide to conserve or use power on a case by case basis.
The product I ultimately purchased was the Anker Astro35. The charger offers four ports and provides one of the fastest and more accurate charges I've found to date for under $40.00 and with over 1,500 reviews on Amazon averaging 4 1/2 stars. Just note a Lightning adapter is required for newer iOS devices to work with this charger unit.