I would assume that these should both extend battery life as it takes quite a bit of power to keep a screen lit up. However, I do not know for certain.
That said: I would find a 90 minute battery very difficult to use - I do quite a few back-to-back shops and periodically have video shops that run more than 90 minutes.... It might be worth your sanity to get a new battery: I have one that's good for six hours. I can use it all day, every day, if I am wise enough to plug it into my car charger when going from one place to another and recharge it fully overnight.
Hard work builds character and homework is good for your soul.