For thru hikers and backpackers alike, finding the right charging system and assortment of other electronics can sometimes be difficult. Everyone has their budget, but also their own preference on what they want out of their gear, so it can be complicated to come to a consensus. There's always a ton of options out there to choose from so it's pretty easy to get lost in the mix of the latest and greatest anyways, so here are some thoughts about my charging system that I've used on the AT, CDT and LT.
As far as charging your phone and any other electronics out on trail, I honestly believe there's a clear winner as far as battery packs, solar panels, and any other options go. If you've been out on any of the trails recently, you had to have heard of the company Anker. They make an assortment of electronics, but specifically thru hikers, and myself use their battery banks.
Both last year on the AT and this year on the CDT and the LT, I used the Anker 20,000 mAh Battery Bank. The option that I chose had the capability for Quick Charge, and weighed just around 14oz. I chose to go with a 20k mAh pack because I charge both my phone and my camera from the battery bank when I'm on trail in between towns. On the CDT, those towns were generally 110+ miles from each other, making for a much longer carry than on the AT, however; I brought the 20k one on the AT as well to ensure my camera would always have a charge. The 20k version yields about 7 full charges for strictly a smart phone, but I generally would charge my camera once or twice in between towns with it as well leaving me 3-4 full charges on my phone. Although the 20k option is indeed just about the heaviest piece of gear in my pack, it was nice to know that I wouldn't have to worry about my map system, camera, or phone going astray.
For most people carrying just their smart phone that would require a charge, I believe the 10k option would be MORE than sufficient. Those come in at right around 8oz, making for a MUCH lighter option that still provides 3-4 charges for your phone. Like I said above, I brought the 20k version because I carry a camera that can charge via USB, but if I didn't carry that camera, I would opt for the 10k version myself. Outside of charging a phone, I don't really see much need to charge anything else, except for maybe a headlamp, unless you're carrying a camera.
Along with the actual battery bank itself, I carried two of the Anker mini USB cables, an iPhone Lightening Chord, and an Anker Quick Charge 3.0 USB Wall Charger which allowed me to charge my devices quicker in town, giving me more time on trail. Having a dual/quad wall charger gave me the ability to charge all of my devices at once and not have to wait on one to charge before beginning the next. This significantly cut down the amount of time I needed to spend in towns.
As far as I'm concerned, theres really no debate about how you should charge your electronics on trail. Whether you're carrying 1 item that needs charged, or 3-4, theres an Anker Battery Pack to suit your needs. They provide the most charge to weight ratio, they are durable, inexpensive, easy to use, and most importantly, reliable. As far as any negative thoughts about the product, the only thing that ever comes up is the charge time for the 20k version. Even with quick charging capabilities, it still requires a good 6-8 hours for a decent charge on it, and around 10-12 for a full charge. I never let my battery pack get below 1 bar, so I never ran into any timing issues, but be careful of that.
They won't kick the bucket on you, and if the sun isn't shining when you need a charge, you don't have to worry. I'll be using Anker products until something better is developed. If you need any more reassurance, I can tell you that I felt confident enough to not bring any paper maps along the CDT this year, relying strictly on my phone, powered by Anker with ZERO issue. Take care of your gear and it'll take care of you!
Anker is hands down the best option for charging along the National Scenic Trails whether you're on an overnighter or on a thru hike.