What about battery charging and hot shower facilities? - Day

Access to both battery charging and hot shower facilities while trekking may vary depending on the part of Nepal one is in and what kind of accommodation options there might be. Some general points follow.

Battery Charging
Teahouses and Lodges Most of the teahouses in popular areas such as the Annapurna and Everest regions have charging facilities available at a cost. Power generation often comes through solar, generator, or hydroelectric systems.
Portable Power Banks Bring a portable power bank for charging during trekking. This would be useful on longer routes where the access to facilities might not be well developed.

Hot Showers
Availability Hot showers are available at almost every teahouse and lodge, but usually for a certain extra charge. Its price can vary from location to location and, probably, depending on the heating method- solar or gas.
Camping Treks If you are on a camping trek, hot showers may not be available, but some companies do offer portable shower tents and water heating for their guests.

Tips
Check in Advance Prior to your trek, check the particular accommodations you are using and what the amenities are like.
Plan Accordingly Bring extra batteries or power banks if you use electronic devices a lot, and be prepared to deal with different situations concerning showers.