It sounds like the battery may be bad or the battery could simply have unplugged itself and needs to be plugged back into the motherboard.
When I purchased the hoverboard, face the same problem. I changed the battery and now it is working perfectly.
I also think of bad battery.but before changing your battery you should reset your board once.In order to reset or recalibrate your hoverboard, you need to make sure your hoverboard is turned off and it's sitting level with the ground on its wheels.
Without moving your hoverboard, press and hold the power button for 10 seconds. Ignore all flashing lights and beeps in this 10 seconds. Then let go of the power button and turn the hoverboard off. The hoverboard is now reset and ready to be turned on.