Samsung j7 is a very good phone in term of battery as well as its day to day performance the hardware has improved now as compared to the previous j7 the phne has got a metallic body.
And also the weight jas increased a little bit due to the metallic frame and according to me thats a welcome move because the earlier j7 was very light and we may not feel it in our pocket .But if you want a good battery backup with higj performance than go for the samsung j7.