why does my battery keep draining ?

Posted by abbasakhtar
Im using a siemens sl65, bought a new battery, let it charge up for about 6 hours, then i used it and it ran out the same day, just general use, the sl65 is about a year old,

i cleaned the contacts and the pins under the cover, but still,this is the 2nd time iv charged it, and the battery is half way and it was fully charged overnight when it ran out last night,

the maximum talk time i got was 2hours and it conked out, the battery is 3.7v 500mah, bought new, it was supposdely high quality, i should get at least 3.5 hours