Is it good to keep laptop batteries charged upto 100%?

It’s perfectly alright, you can work no problem

Well, modern batteries are intelligent enough to know whether they are fully charged or not, once they are completely charged the laptop automatically stops charging and starts working with direct D.C supply from the adapter.

I always connect my laptop to charger when i was in home and places where i have facility to connect.

This makes my battery give backup like the new one even after two years.

by the way, it will not increase the temparature. It even cools the laptop, because during charging battery heats up, it makes laptop hotter. If you connect it with charger, laptop works with D.C supply from adapter directly without the involvement of battery. so no heat will be generated from battery.