Hi there.........your fault you have described is the most common cause for the main carriage batteries need replacing in the stair lift carriage..the life of the batteries can be anywhere up to 3-5 years depending on wear and tear of lift...........checked first that the mains supply has not been turned off by mistake as this can happen quite often,causing the batteries to drain,if the main switch is on your looking at new batteries,hope this will help........paul/portsmouth
paul
July 2014