Hello. I started having trouble with my Nest thermostat losing battery. I had to remove from the mount and charge with USB but it only lasts a day or two and weakens again. I see the lin is at 20ma and I read that this is the bare minimum. So I tried to add a 24v power supply with a C wire which doesn't exist in the original wiring. I have an ac unit with a heat pump. When I added the 24v power, the lin went to 200ma which was good, but then I got an error message that the Nest couldn't find the ac/heat unit any more. It will not run on ac or heat with the 24v power attached. When I remove it , it works but doesn't charge properly.
My wiring is set as:
y1 - yelllow - cooling
G - green fan
Rh - red - power from unit
O - orange - heat pump valve
W - white
When I added the power supply I ran red to (hot) to Rc and white to C. that's when the nest could not longer recognize my unit. I don't know what to change to get this to work and charge.
