Hi Dave,
Your BB1 should have come with a power adapter. As Peter says it is a standard 5V 2A USB charger type adapter, which you may already have from a mobile phone or other device. If not please email us on - thebrennanb2 @ gmail . com - no spaces.
Other owners on the Forum are using rechargeable Lithium batteries which they say last around 8 hours between charges. Power banks (the devices you use to charge your phone on the move) have also been mentioned.
Paul
Brennan Support