Updated: Sep 8, 2018
Electronics are increasingly a part of mountain bike setups. Lights and cycling computers are almost standard issue and they need a power source. Then add your phone, tablet and camping power requirements and it becomes clear that this is an important part of planning a multi-day trip.
There are some great gadgets out there from solar to generating hubs to meet your power needs on tour. However these solutions will take a financial investment, something to consider if you do regular unsupported journeys.
I found what I think is a great portable power solution that combines a hydration pack with a solar charging station! With a bit of online research you will find the best solution that works for you.
For most of us power is usually in the form of a battery, but they are limited in capacity. For longer rides and tours you will require some sort of backup power or charging point at camps. Make sure to ask if there are charging stations along the way and plan accordingly.
I suggest that an extra set of batteries is carried for your devices. It is much simpler just to do a swap vs. carrying solar chargers or power banks with you.
Most mountain bike lights carry a rechargeable battery, and if you plan to do a lot of night riding solar or a backup power bank will be a solution.