No complaints here. Just want to know how to get a new one installed, preferably in Chiang Mai? 

Don't expect miracles if you do change out battery on your Pixel

 

Had a new, larger capacity battery , installed in my Nexus 5 X and my Nexus 7in pad,   with no increase in run time

 

Fairly simple process so long as the shop knows where the latch points are on the phone 

Replacing the battery yourself, or having a local technician do it (with a reference to one of the many Youtube videos), isn't really the major challenge. Finding a suitable replacement battery will be.

 

I guess you could check with HTC Thailand, or maybe order one from Amazon/eBay in the U.S. (shipping batteries remains a challenge in and of itself), then ask a local tech to do the replacement? Or maybe if you know someone coming from the U.S. you could order one or two for delivery to them, and then ask them to hand-carry them, preferably in their cabin bag.