The Jackery Solar Generator 300 can be used to charge the Shimano Steps E-Bike battery.
I looked at the Jackery Solar Generator line-up and I believe that the 300 is the smallest unit that can be used to charge the Shimano Steps Battery. I wanted this ability for a few reasons.
1) when camping and away from the Grid, the Jackery Solar Generator can charge while I am off riding. It can then be used to charge up the Shimano Steps Battery.
2) with the Solar charging ability, I can use to Jackery making he E-Bike a "solar powered" E-Bike.
3) If I needed to, I can pack the Jackery for short overnight tours, having a little less range anxiety.
It is able to charge the Shimano Battery to about 30% in a couple of hours.
A solar panel is used to charge the Jackery 300.
This is a good option to be able to add power to the e-Bike when your are away from the grid... or just use to have a "solar powered" e-bike.
In the future, there will be better options (smaller, less weight) but this works for now.