I want to buy a MacBook Pro 2016, probably the 15" model.
Since I travel around on my bicycle a lot, I'd find it really nice if I could charge it with a solar panel. Does anyone know how much Output a solar panel would have to have to power a MacBook Pro via USB?
What I would recommend is going iPad Pro and keep a Mac mini somewhere else for things you simply cannot do locally. Since you are looking at the new models that accept USB C charging, you have lots more flexibility to use solar / iOS type chargers than before. The early 2017 lineup has 4W to 35W processors instead of the much higher wattage ones from 2016 and older.
Even so, running LTE network and remote access to where you have AC power for your Mac keeps your bicycle build light and reduces your cost for solar 10x or more.
I personally wouldn't bike with anything bigger than the MacBook with USB-C charging or iPad, but you could be thinking of a trailer where 35 pounds of gear and Arizona type sunlight would make a MacSafe MacBook possible. Also, the MacBook come with 29W, 61W, or 87W USB-C Power Adapters so you can pick a solar panel that would mimic those recharge rates. It's possible you could get away with a 29W charge on the biggest MacBook if you didn't run down the battery but 1/5 of the way each day and had good times to charge it (i.e. all day on the back of the bike in clear conditions).
I have heard of people using the 13" and 15" MBP for light work and running all day on a 10W range iPad charger. They lost battery charge all day and watched CPU intensive tasks, but for email, light web, no video or no encoding work - they made it most of the day with less than 10% battery loss and regained 25% battery charge with the Mac sleeping all night on the iPad charger. Now you have USB-A to USB-C charge capability with a small cable instead of lugging a MagSafe AC to DC transformer.
In the apple.stackexchange.com post on powering a MacBook Off-Grid which although not exclusively limited to solar- wind, pedal-cranked generators, whatever you could think of to power a Mac Off-Grid- I give granular detail on configuring a Portable Solar Power System to power a Mac:
https://apple.stackexchange.com/a/383779/319348
It's a pretty fair primer on getting started with solar and tells you all the key considerations for sourcing the correct- and compatible - components to work very remotely with your favourite fruit-based computing device.
A companion video demonstrating the solution for this apple.stackexchange.com post can be found at:
https://youtu.be/5STIzh6JCXkenter link description here
Since it uses a large 12v battery, would probably would more suit somebody traveling with an RV with a bike on the back of it, or working in a cabin however. HTH-
I have a 2016 15" mbp with usb c. That laptop comes with a 87w charger, but I have found that even a 5w charger will refill the battery if left plugged in long enough. I've also done a good amount of bike commuting and have the dream of charging my laptop via solar. Currently I am using a 28w foldable solar panel with usb ports off of amazon. They discontinued it but it has a 15w usb c port that usually lets me get through a day's work with a mostly-empty battery at the end of the day. There are also plenty of usb-c power banks that charge at 30w-60w. I think 2 batteries like that soaking up 12w each and one of those 28w usb solar chargers would be enough to keep you going most days that there is sun.
