We've been getting quite a number of complaints from Tecno F7 users about their battery levels remaining constant or even dropping despite charging for several hours. Here's a quick troubleshooting guide to help resolve this isssue.
Note: Ensure to read this guide @ http://blog.hovatek.com/how-to-fix-an-an...er-source/
A Tecno F7 not charging or experiencing a dropping battery level despite being plugged to a power source points at three possible problems.
1. Faulty charger
2. Faulty battery
3. Faulty port
* Its possible the charger is not powerful enough to charge your phone. Try using a desktop charger. If it charges the battery of the Tecno F7 normally then that rules out a battery problem; so its either a charger or port problem.
* Try using the same charger on another phone and observe. If it charges the other phones normally then the charger is ok, making it either a faulty battery or faulty port issue.
Try charging the battery with a desktop charger and observe how long it lasts after a full charge. If the battery drains quickly then its either a damaged battery or your Tecno F7 is not well optimized for reduced power consumption ( See How to make an Android phone's battery last longer)
* Charge the battery with a desktop charger. If the battery lasts normally on the phone then you might need to change the charger to a more powerful or firmer one to make proper contact with the port.
* Try mounting the mass storage of the phone on a PC. If the PC is able to read the phone's memory card properly then that rules out the port from being the problem.
If the issue persists despite changing all these then consider re-flashing the stock ROM using Sp flash tool @ https://forum.hovatek.com/thread-159.html
* Faulty charging Diode
If all the above methods fail then consider changing the charging diode