If your Acorn stairlift is beeping, it is not receiving enough voltage to charge the battery. Check to ensure that your battery isolation switch, a flat round button with a small green indicator light, located under the seat and to the left of the key is turned on. If it is off, press to turn on, activating the green indicator light. If the light does not come on or the beeping does not stop, call Acorn immediately to schedule a service visit from a technician.