DIY : Power Backup For Your Router
We get to solve different kinds of problems. One of the major problems I had to solve was getting a stable internet connection. When you work from home, having a stable internet connection as well as a stable power supply is essential.
In my area (or rather in my country :) ), a stable and consistent power supply cannot be guaranteed. You would experience planned power cuts which will last for hours and sudden power failures. Either way it would affect your day to day work. Imagine you having an important meeting or work to do and experiencing frequent power failures.
In market you would find many power banks and battery backups which you can plug in for your router. When I had a look, it turned out that those are using a BMS(battery management system) and some Li-Ion batteries.
So why not do it yourself :)
We would need following items
BMS x 1
There are different types of Battery Management Systems. The one I used was “3S 12V 18650 10A BMS”.
3S means 3 batteries in series. 12V is the operating voltage and 10A is the max supported current. 18650 is the supported Li-Ion battery size.
This tiny board comes with elegant features like Short circuit protection, Overcharge protection, Over-discharge protection, Overcurrent protection etc.
Li-Ion batteries x 3
Battery size need to be 18650 and the capacity(mAh value) can be of your choice. I used 4300mAh 3.7V 18650 Rechargeable Li-Ion x 3Pcs. Altogether 12,900mAh. When fully charged this could keep my router on for more than 6hours during a power failure. Of course you can increase the capacity by either adding high capacity batteries or by increasing the number of batteries. If you add more batteries then that needs to be multiplication of 3 as the BMS board support 3 series batteries to produce 12v. eg: 3,6,9 batteries
Battery holder x 1
DC Connectors (male and female)
Battery Level Indicator x 1 (optional)
12v DC Power adaptor with current > 3A
Usually a router takes ~1.5A current. To charge the batteries we would need another ~1.5A current. Therefore we would need a power adaptor which provides the current higher than 3A. I used a 12v 3A power adaptor.
Wiring
This is how you need to connect your batteries to the BMS board.
Below both diagrams are same. I added both for more clarity.
Then connect BMS board’s + and - terminals to DC connectors and the battery capacity indicator.
Thats it. Pack everything in to a nice container. I used an old plastic box :)
Budget
I purchased everything from local shops in Sri Lanka. Actually I ordered everything from online sites and was delivered to home. I wouldn’t mention the sites or the links here. Just search in your browser, you would find the same :)
BMS board — 350LKR
Batteries — 395 x 3 = 1185LKR
Battery holder — 135LKR
DC connector female + female — 40 + 40 = 80LKR
Battery capacity indicator — 260LKR
Power adaptor — 800LKR
Total = 2810 ~ 3000LKR
Enjoy 6+hours of power backup for less than 3000LKR :)
