Sparkfun published a nice article about Nest teardown.
I wonder if the battery is replaceable other than by "contacting technical support" (update: from the link below - no, it is not replaceable).
As usual, comments are as useful as the article if not more.
C Wire-less SetupIn particular, here's a link to an article describing a subtle problem: Undocumented Nest incompatibility with single-stage wiring. Incidentally, all three of three HVAC units I have do *not* have the C wire. Here's what Nest has to say:
- When Nest needs a common "C" wire
- Should my B wire go in Nest’s O/B connector or in the common (C) connector? (this one is actually very important because it is a thinly veiled liability disclaimer ("If a common wire is inserted into any connector other than C, it may blow a fuse in the HVAC system and damage Nest"). Be sure that your B wire is not actually a C wire. It would be nice if they provided a way to determine this for sure using something as simple as a multimeter, more on this later.
- Power Specifications for the Nest Learning Thermostat
- Does Nest need a common wire?
- What do Nest's wiring errors mean?