Jim
I just use a power station. one of those rechargable battery
things that has jumper cables to jump your car and AC outlets for lamps or other things and they usually have usb charging ports. they are around $100 and will last for at least 6 hours for a keyboard. all differant brands at home depot, lowes walmart ect. Plus I have my bose s1 pros which will run on internal batteries.
MEL