Ur battery is 12V at 9Ah. So that's what it supplies. Due to which it gets discharged and ur recharging it with the coil! (I may be wrong too, am very weak in all these electricals and electronics from +2). Better ask Santoosh, he is the best person for all these electrical stuff. No problem with a 35W HID man. In that case with ur Avenger coil u probably will be over charging the battery. the normal life of a battery depends on usage. If u go for a 55W HID U can get out of that problem too. A max of 18 - 24 months is the avg. expectancy of a battery. I swear by EXIDE or AMARON.

Oh! Cool. Apar saar. One more question. Just out of curiosity. What is the maximum power that the stock battery can supply? At later stage, if I'm going in for HID, do I need to change the coil/battery again?
AND, what's normally the life of the stock battery? Which is the best replacement for it?

If u change the coil there will not be any issues. Since ur using a 55/60 there will be extra load on the stockcoil. Ur compensating the same by using a higher wattage. Its absolutely cool!! No issues. I wud recommend that upgrade in fact to evry Pulsar owner!!

And will the total power be good AFTER I change the coil? I mean, will my horn sound weak when I honk while using the light?

Yes changing stock coil is compulsary as ur stock coil is designed to output only 35W. Else u can remove the pilots and use the 55/60. Even then power will not be that great.

If u had asked me 15 days back I wud have given u the Avenger Coil. I had used it on my Pulsar and now Badri is using it. The coil costed 780 when I bought it. U will get the coil in Probiking. Its just plug-n-Play. As for the light, Check out GP road car shops. Ask for Osram NB 55/60W, H4 with P43T socket. Or check online for shops.

Apar saar! I need your help! Where can I lay hands on an OSRAM nightbreaker? How much will it set me back by? And do I have to change my stock coil if I'm to use it? Which coil do I use?