I've got Drakino's old Gen1 nest and last night it failed because of a low battery. It was cold in the house this morning.

I can top of its charge by connecting it to a USB charger, and then when I put it back on the wall it works for a while before complaining about a low battery again. Though the indicator screen indicates that there is 37 volts of power coming to it (which their online troubleshooting wizard seems to think is sufficient), it doesn't seem to be successfully keeping the battery above its "low" threshold of 3.6 volts. Since, up until today, the unit worked fine, it looks like it's time to replace the battery.

Looking at the teardown pics, it seems that the battery is a straightforward LiPo unit with a connector plug. I should be able to just replace this puppy by ordering one online somewhere. But google searches aren't coming up with anything.

Anyone know whether I could get one of these things from, like, Digi-key or something, and which one it would be?

Another possibility is trying this guy's hack...