Both Nest Learning Thermostats lost power and won’t recharge

[Bjer1973]

Both of our Nest Learning thermostats (2 zone HVAC) lost power in a storm and will not turn back on. We’ve taken off the base and charged with USB but they don’t stay charged and shut off after few hours. Any ideas? 

[Raphaeldlv]

Is your heatlink still functioning? I have a similar problem, but my heatlink won’t power on with 240v but will show some activity on usb.