hello. can anyone recommend me a laptop that is optimum for CS students like me?

Preferences(Major):
-Budget: 2000-3000
-At least 3 to 4hrs of battery life
-4 RAM will do(i guess..), not too high/low
-Purpose: for coding/programming either in IDE or terminal + text editor, oh and also less emphasis on gaming since i rarely play PC games
- Good warranty and after sales services

Preferences (Minor):
-Brand: Any will do, though I've been hearing good things about HP when comes to battery life.
-Weight: Don't mind if it's bulky/heavy/light
-anywhere between 13 to 14 inches will do
-Do not overheat rapidly

P/S: My current notebook (ASUS X540LJ if I'm correct) battery life only lasts for under 2hrs. I've been using it since Dec 2013, hope I'm able to get a decent laptop that has a longer battery life. If it weren't for it's battery flaw, then I would've keep using it for much longer period... Thanks

Thanks for the recommendation. I'll look into them further.

Nice, thanks for the recommendation.

Oh btw, this might sound a bit silly but, is there any distinct advantage between a laptop with removable battery and the ones without removable battery? My previous Asus laptop's battery is unremovable(have to send to shop if need be..) and compared to my peers, mine lasted only roughly like 3 years, whereas theirs with removable battery is still going strong, and their battery life is way way more longer than mine....

yeah, i feel so... so where do i start with, lenovo? is HP/Dell okay too?