I have a asus router with a power rating of 19V @ 1.58A max for which I need battery backup for 1~2 hrs daily because of power outages.
Now I have 12V 7AH exide battery of an old ups which still works.
I also have a 12V 2A power adapter and a universal laptop charger which provide variable voltage from 15V to 18V at 4A and from 20V to 24V at 3A.
There are many lead cell charging circuits out there, BUT all of them are designed to output 12V where as I need 19V for my router.
@FvM
My router is always running at maximum power with a 1Tb external drive and about 7 devices connected across a two storey building, So i would say the router is drawing max power which is 19V @ 1.58A