I started with trying to find 2 UPS for 2 of my routers with the following input specifications:
- 12v 2A
- 9v 0.6A
I realised that buying 2 power banks will be economical than buying 2 UPS for the AC power source.
I started searching for the power banks with the output specifications which matches my routers' input specifications. I did not have issues finding the 9v 0.6A. However, I am unable to find the 12v 2A, except for car jump start power banks (which are very costly and I am not sure if they allow charging while connected to the router at the same time).
I thought of building one by stacking sufficient Lithium-ion 18650 batteries should not be difficult with configurable output voltage and amperes.
I came across these instructables
But none of the above matches one of my router's input specs (12v, 2A)
I also checked other questions on StackExchange, but not very helpful, example:
- Powering 12V 2A device from high-power USB portable charger - No conclusive answers.
- Creating a Li-on backup for a 12v router - Good schematics and answer but the output specs does not match mine.
So, I landed up here to understand how this can be built. I am based out of Bangalore in India and I would prefer to procure materials available here.
- Build a power bank which can charge itself and also power the router at the same time (work as an UPS)
- Display output voltage and current preferably
- Configurable unit on the built device which can moderate the output voltage and current.
- Battery overcharge protection unit
- Under and over voltage protection
- Cost effective - I am ok to sacrifice point 2 from the above to cut down on cost! I can always use a voltameter to check the output specs manually ;) Fine with leaving behind point 3 as well and have a fixed output instead of variable one, however, I would love to have point 3 covered!
This is what I can think at the moment from requirements perspective, is there anything else I should consider?
I am very naive at electronics but very much interested to learn and build :) Looking forward to lots of fun and education from the community and a fruitful product!!