DIY 12V UPS for home network equipment
I have a small cabinet for modem, router, network switch and 8-port patch panel. I've managed to squeeze in a small UPS as well. When I finally got DOCSIS 100/20 Mbit Internet, the cable modem was so big that I had to make some changes to the cabinet. It is good to have an UPS for the equipment. Internet usually works during short power outages and the equipment is not damaged by hard reboots. It also protects somewhat against voltage spikes. So when all of the equipment runs on 12 V it got me thinking. Why do I need an UPS that converts 230 V AC into 12 V DC (for the battery) and then to 230 V DC again, and then at least three small adapters to convert it separately to 12 V DC again? Instead I could replace it with one larger 12 V DC power supply combined with a battery. I found a 12 V UPS, a Mean Well AD-55A . It outputs 4 A at 13.8 V DC and a small battery can be attached (charge 13.4 V, 0 - 0.23 A). Output voltage is adjustable between 12 - 14.5V. It has of course to