I'm wondering if/how the new Garmin Edge Touring allows for updates of its underlying OpenStreetMap (OSM) data.
I do not believe this is clear just yet. I have not seen any reference from Garmin to indicate the availability and method for updates.
If updates are available, they will be through Garmin's map update
page. The current tool for updating maps on the Edge series is Garmin Express
Meanwhile, the unit itself accepts SD cards that you can load with new and custom maps
To load the latest OSM maps on the Touring unit or any other unit for that matter, take a look at these two references:
BTW, I'm an owner of more than one Garmin GPS device, and I REALLY do prefer the much-greener NiMH (rechargeable via my solar panels) AA batteries. If a device doesn't use AAs (and NiMHs well), I might not buy it, and I'm not alone!
The unit has built-in rechargeable lithium-ion battery accordingly to the product specifications
page. This is the same for all the Edge series units.
Can you elaborate on your experience with solar panels in this other discussion: Solar Panel - Yea or Nay?
? The general feedback was "iffy" at best.