I have an abbey freestyle 540 (2006) have just returned from a long weekend away, on mains with charger on, showing 14+v no probs for a couple of days then noticed the meter was only showing 12.3v and would dip with usage, switched illuminated charger switch off, no change, then back on again with no change, although I assume there is mains power to the charger as the switch is lit when turned on, it seems as though there is no output from charger as the meter only shows low to mid 12v. Can anyone please advise of the possible cause/fault