Very few people have ever had good experiences with generic batteries. Either they don't work at all, or work for a short time.
My advice is to make do with one battery until you can afford a real Nikon battery.
If you start out shooting with a full charge, you can normally get several hundred photos out of the original battery. They are very good. One of the main power sucks is the display--go into the menu settings and set it for the shortest automatic off time, and minimize your use of it while shooting.
working on it in Middle TN Nikon D3100
35 mm 1.8 Nikkor 18-55 mm Nikkor VR 55-200 mm Nikkor VR 55-300 mm Nikkor VR 150-500 mm Sigma OS Feisol CT3471 & Markins M20 ballhead