Rechargeable Battery Base for Google Home Mini - 7000mAh Portable Charger by Wasserstein (White)

Q: Instructions lack info on charging base - usb/micro to computer? usb/micro to wall? must mini be attached to charge? how long to charge?

Use the usb that came with the Google home mini About 4hrs and you don't have to remove it from the base but it will take longer if you are using it

Q: Is this fully compatible with nest mini? since they got rid of microusb port and connector.

The name of the product suggests that it works with the Nest Mini, but I don't see how, if the Nest Mini doesn't have a micro USB port. The battery connects to my Home Mini via its micro USB connection. I'm not saying it won't work, but I wouldn't buy it for your Nest Mini unless you can get either the seller or someone who uses it with a Nest Mini to confirm that it will work.