[quote=“rizwansadiq, post:4, topic:21667”]
Use 12V 7Ah dry battery with 13.8 Volt Charger and take desired outputs by using 78xx regulators or LM 317T you can get backup time of minimum 10 Hrs with DSL Modem (12 /9VDC and Mobile Charging (5VDC).
Note: Little know how about electronics required for assembling above arrangement, but after using you will be happy. for more safety LVD(Low voltage disconnect) may additionally used to prevent deep drain of battery(below 10.5VDC) if unattended longer shutdown of utility(more than 10 Hrs)
rizwansadiq, this is indeed a very good solution. My soldering skills are bit rusted, but I still have a soldering iron in the attic. May even have a 7805 lying around from my college days. I guess that I can do it, but will need more than a description -- a schematic will be quite helpful
As far as I understand, the above solution may not have automatic switching to battery power (when there is no electricity), and automatic battery charging (when the electricity is back). How complicated will it be if an (automatic) UPS with 12V, 7Ah battery is built?