Here's info for your Galaxy J7 V / Galaxy J7 (2nd Gen.), including tips to extend battery life.
Battery Specifications
3300 mAh Li-Ion non-removable battery
Up to approx. 38 hours Use Time.
Up to approx. 14 days Standby Time.
Battery Basics
Battery life depends on the network, signal strength, temperature, features and accessories used.
It's common for batteries to be warm from use or charging.
This device has Quick Charge 3.0 capability with cool charge - up to 50% charge in 30 min.
Battery Care Tips
Avoid exposing the battery to extreme heat and cold.
For the first 3 charge cycles, fully charge the battery overnight and allow it to fully discharge before recharging (battery conditioning).
A Lithium-ion battery may be damaged by extensive overcharging (continuously on a charger for more than 24 hours).
Use the battery. If possible, avoid letting the battery sit idle for long periods of time.
Use only the device options and accessories that are really needed.