The inReach SE, inReach Explorer, inReach SE+, and inReach Explorer+ charge via a micro-B USB port. This means that any charging device that has a USB output will be able to charge the inReach device. The charging times will vary since USB current can be anywhere from .5A to 2A. 

Mirco-B USB sample picture:

Sample charging devices:

• Solar panel: http://shop.inreachcanada.com/collections/inreach-accessories/products/goal-zero-guide-10-plus-adventure-kit
• External battery pack: http://shop.inreachcanada.com/collections/inreach-accessories/products/goal-zero-guide-10-plus-battery-pack

A full list of charging accessories can be found here: http://shop.inreachcanada.com/collections/inreach-accessories