Unless your traveling under candle light, with map and compass in hand its almost certain that you will need to power your electronic devices during your travels.

In our experience there are two ways the travelling cyclist can do this,
Option 1: Charge when you stop
This means carrying with you a power bank, and mains outlet wall charger- so whenever you stop you charge your devices.  In my experience a multi plug wall charger works best- as you can charge lights, GPS, Power Bank ect all at the same time.
We always advise using one with a two piece design, as this allows you to plug into areas with limited access, and if needed get a plug with a mains connector appropriate for the region you are traveling within.
High wattage USB ports are recommended as they will charge your devices the fastest, ideally have at least 1 USB port that supports USB QC3 (Quick Charge 3). As this is the fastest way to charge most modern smartphones- and some power banks.
Option 2: Dynamo Charging
Dynamo charging is a great option if you are planning to be on the go constantly, or travelling for a prolonged period of time. Dynamo systems mean you can always charge up most devices while moving- be it fairly slowly.
We always suggest viewing a dynamo system as a ‘top up’ charging system- as its most effective at maintain charge- rather than being used to recharge depleted batteries. As such our preferred way to tour is with both a Dynamo, and a mains multi USB power supply. This means when we stop at a café, or camp site I know I can fully recharge most of my devices overnight in one hit- then just use the dynamo while moving to maintain charge on my power bank.
This also means, should USB mains charger or dynamo fail you have got a level of redundancy built into charging system.
View our range of dynamo charging devices here (Opens New Tab)  

Other notes:
In our experience, micro USB cables have been the easiest to get hold of, and as such we suggest carrying adapters. These will allow you to convert a micro USB cable to Type C, or Apple Thunderbolt. While you should carry all the cables you need for your devices anyway, these tiny adapters weigh nothing and can help you get out of a jam should your primary cable fail.
We also highly recommend using power banks with USB C type connectors, as these have proven to be more durable than the other micro-USB type. They are also reversable which makes it less faffy to connect to.