At first when i charged the battery there was red light but later on it became blue so i unplugged the charger and charged it again it it started to blink 8 times in blue colour .
Hi Nirdesh and welcome. eGo type batteries do blink (8-10 times) when you take them off the charger. Nothing to worry about yet. It's normal--it just tells you that the charging process has been interrupted. Generally speaking, the light on your battery should go from red to green for fully charged.
Evod batteries come with several protection features that will cause the battery to blink rapidly:
Low voltage (over-discharge) protection: When the battery voltage is lower than ~3.3v, the battery will shut down before causing any damage. Make sure your battery is properly charged. Use the USB cable that came with your battery and a wall adapter (5V, 1A wall wart) to charge your battery. Do not charge from your computer unless you absolutely have to, especially if your battery is acting funny. You don't want to damage your computer.
Atomizer protection: 10-second Safety Cut-Off Feature to stop the atomizer from activating for too long and overheating or shorting. In other words, if you press the power button for longer than 10 sec, the battery will shut off.
Short circuit protection: When a short is detected, the battery will shut down until the short is removed. In other words, if your coil is damaged in any way (very low resistance or broken), your battery will not work. With the old eGos, a short would have killed your battery in an instant (don't ask me how I know). I hope this is not the case with the Evods.
So, if you're sure that your battery is charged properly and is turned on (5 rapid clicks on and off), you should examine your atomizer. Take it off your battery, remove the coil and install a fresh coil. Do you have an ohms meter, by any chance? Or a different battery you can test your coil on? That would be helpful. If not, just try a new coil--do not over tighten your coil and your atomizer--just screw everything in place until it fits snugly, but not to tight. If you over tighten your atomizer, you'll depress the center pin on your Evod and you won't be able to achieve a proper electrical connection.
If your center pin is already depressed, you may try to raise very gently (use a paperclip or tweezers) to its original position. Very gently!!!!
Or get a couple of those--this little gizmo will fix all your connectivity problems on any mod/atomizer.
Circuit Board Spacer - Madvapes
Once you have your new coil installed and your tank filled with eliquid (off the battery!), turn your battery off and on again to "reboot it," unplug and plug in your charger, put the battery on a charger again to make sure it is charged, take it off the charger, attach atomizer with new coil and see if that helps.
Good luck--and keep us posted.