Flat battery in new pucks?

I did this in conjunction with https://github.com/dokterdok/Continuity-­Activation-Tool/

To force your system to use an external Bluetooth controller instead of the internal one, open Terminal and type:

sudo nvram bluetoothHostControllerSwitchBehavior=al­ways
then reboot. To revert to the default OS X behavior, type:

sudo nvram -d bluetoothHostControllerSwitchBehavior

You may need to turn off (or un-pair) Bluetooth accessories that are currently using your internal Bluetooth controller, as they can prevent the dongle from being detected by the Continuity Activation Tool.

The end bit was key. turning off the bluetooth devices and then bluetooth, then firing it back up finally did it for me.