I have been working on a small DIY project. Reference for this project is the following video from YouTube. DIY - 12V Mini UPS
While I was able to put together everything and it works for most part, I see one issue and need some help there.
The device works from the backup perspective. So, when I have power from the mains, the router works on mains but when power goes off, it works on the batteries from this device.
So, when I started, the batteries has full charge so I was getting 8.4 volts out of them. To check the working I turned off the main power. After sometime I checked and as the voltage had dropped to 7.5 volts I switched on the main power. While the router did not have any interruptions due to this, I noticed that the batteries are not getting charged even when I have main power available.
Question - Does this type of BMS charge the batteries? This is one of those cheaper BMS available online through a number of sites and from the description of it I had the impression that it charges the batteries as well. The actual link from where I bought this BMS is mentioned below. 2S 10A 18650 7.4V-8.4V Lithium Battery Protection Board
Any help will be appreciated.