This is a kind of 'Hack' to help you, we are not saying it will work with all models and on every single device...but it will help some of you out there!
A common issue when connecting a battery up to a new control board or a board that has no power is a big spark. Now as long as a quick and solid connection is made this isnt the end of the world, but if you plan on doing it several times its a good idea to try and limit the spark. The spark occurs as the capacitors are empty, and are filled rapidly as soon as power is connected.
What you can do to solve this is to simply use the motor as a generator to 'push' power into them BEFORE connecting the battery. The MOTOR cables must be connected at this point to complete the generating circuit.
See a quick video: