I have a need to organize some kind of battery backup power supply for my adsl router ( 12v dc ) and the simplest option available to me is to use a spare UPS box. However, this strikes me as being a bit OTT as the power supply for the router will have to convert the mains output from the UPS in to 12v dc. A simpler solution, perhaps, would be to connect the router directly to a 12v battery ( such as the small 7ah batteries used in the UPS ) and then connect a trickle charger to the battery - thus saving space and doing away with the need for all the switching and power conversion gubbins.
Does anyone here know if this is a reasonable proposition, and if so what would be the requirements for the trickle charger?
Regards,