You classify your TV as 'essential equipment' You need to get your priority's straight! Seriously though, it's FAR cheaper in the long run for home use to purchase an inverter battery backup system than it would be to build one, by FAR. And modern UPS power supplies are far more sophisticated than most home brew systems. Check any major electronics store, especially one that sells a lot of Computer products and talk to a salesmen. They're plug and forget. You still need to replace the batteries about once every 2-5 years.