Each time that my Philips T162 beard trimmer appears to be run down I remove the adjustable head, unlink the blades and switch it on. I leave it like this for an hour to ensure that the battery is completely discharged. Now recharge the battery in the usual way and it should last much longer than previously. If this trick does not work than, as another reader suggests, buy a replacement battery if possible, or a new trimmer.
Unclemac, September 2008