1,3,5 on a battery LED means that your battery has a problem. Best you have it replaced immediately.

Yup, that or flashing lights indicate a failed battery. Ask dell for a replacement and see if it is not required to do a bios update (which provides a better charging algorythm). HAppened on my old 8100 and I had to update the bios as well

BTW, as I understand it, the Inspiron 5000 is already EOL, so chances are your battery may be beyond the one year warranty. If it is, purchase a new one instead.