Well, by now I guess it's clear that your battery problems are from bypassing the registration. Because the device is not meant to run unregistered there is some process that keeps running until it is registered.
Just register it with an email address. Doesn't even have to be a real one. They don't check. I have set up a BN account that I use exclusively for registering devices that I give away. People over here can't buy from the BN store anyway, and I don't have to put in any credit card details. But, like I said, you don't have to set up an account at all. Just put in an email addy and go!