Synergy Digital Smart Home Battery, Compatible with Nest Learning Thermostat 3rd Gen Smart Home, (Li-Pol, 3.7V, 380 mAh) Ultra High Capacity, Replacement for Nest TL284443 Battery

not too much instructions with replacement, but if you google the battery and the thermostat it tells you exactly what to do (video)

This battery is extremely disappointing. It lasted one day then died. Very unsatisfied. Do not buy unless you like wasting money.

Item works fine.

My gen 3 Nest battery died. I could charge it via USB and it would work for a little bit. I moved my basement thermostat in the malfunctioning thermostats place and it worked great. Tried this battery but it is only putting out 3 4 volts when 3 8 is required. Going to return this for a refund.

Bought this battery to replace the factory battery for my nest learning thermostat. It is not the exact same voltage or capacity, but would work. It is larger than the factory battery, so much harder to install. It still worked though.

The battery would not take a charge even after leaving it plugged into a charger overnight. The seller/Amazon replaced it promptly. The replacement did the same as the first battery. I was promptly refunded when I returned the second battery.

This is a bad product; the battery will not hold a charge.

DO NOT BUY! The wire is too long compared to the nest battery. The extra length of the wire when coiled up broke the chip in my nest. So this piece of crap battery broke my $200 thermostat.