Panasonic CGR18650CG 4S módem router back up

[Venezuela Solar]

I'm planning to use this (see link) second hand packs to make an small mini ups to back up 3 routers and a modem, I know that this packs have more than enough energy for routers, but, the thing is that some times we loose power 6 to 8 hours and last time was 14 continuos hours and if things go bad it could be days.

So the real question is that this packs ranges from 12v (3v per cell) cutoff voltage and 16.8v fully charged, the power brick of the routers say 12v1A , do I need a buck converter? Or a buck/boost converter (I haven't be able to find one of this that convinces me)

Also, every 16.8 charger that I found looks like a cheap 2 uses power brick.

If I were to charge this pack with a 30-40w solar panel, would it need a charge controller, MPPT I guess it that case.

I plan to use 5.5mm barrel plugs for easy connections

Thanks

 

[DIYSteve]

You would need to design a circuit with a relay to switch between AC supply and the backup lithium pack. The AC to DC converter that normally supplies power to your modem will also need an attached circuit to recharge the lithium pack when required.
Secondly the lithium pack will need a regulator or buck converter to ensure a constant 12v to your modem.
Hope this helps you.

 

[Venezuela Solar]

You would need to design a circuit with a relay to switch between AC supply and the backup lithium pack. The AC to DC converter that normally supplies power to your modem will also need an attached circuit to recharge the lithium pack when required.
Secondly the lithium pack will need a regulator or buck converter to ensure a constant 12v to your modem.
Hope this helps you.

Actually, i dont thing i need the relay, the routers and modems i have work with DC, so i will be DC to DC conversion, the thing is the power supply/ charger that i need, most of this items are very cheap bad chargers, i think i will be using a laptop with a converter.

 

[DIYSteve]

Your right, I assumed you would tie it to the supply before the AC to DC adaptor. It does make a lot more sense to just tie both DC lines together.
You could add a charger to the cells that only kicks in at about 75% SOC.