hello , the lights will survive until the battery fall down  , because someting has happened and prolly you have a damaged or weak alternator or worne regulator ( best option ) 

where you read this 14 v ?  At the battery with engine run  with a voltmeter ? 
 If yes you have a problem on voltage regulator , you should have  1,5 volts more on 12 volts battery .
voltage regoulator job is to give always the same amount of juice , 14 is too much 13 is not enough 
If you ride a lot of time  you will discharge battery completely until lilghts will not work , than  the car will die without any juice.
Or you can have one of three " points " of altrenator damaged , still make some volts but gonna broke easy

My volt meter often reads 14.1 volt right after starting the car.  Soon afterwards it drops to 13.3 - 13.8 volts (varies).  A temporary reading of 14 volts is okay when the system is charging.

With the car running and you measure +14 to 14.3vDC, the alternator is charging the battery.  As another post indicated, this should drop to the 13.8vDC, or so, within a few minutes.
I'm not sure how the alternator light is powered on the solid-state regulator, but I'd start with the wiring, make sure connections are all tight and clean.  If that doesn't work I'd look into the regulator.