I have two of these. I brought one down to Costa Rica to deal with the unexpected power outages that happen on a semi regular basis. I connected two 12v - 100 amp hour deep cycle batteries. This will run a few lights, my electronics, wifi, computer, music and short use of tools for a day or more (maybe longer). I would leave equipment with higher amp draws (like the refrigerator, pumps, washer, dryer, air conditioner) off the same power out electrical line or expand the battery bank for some mid amperage use.  When set to operate automatically and grid electricity goes off, this inverter takes over and supplies the 110 volts of electricity from the batteries via its' inverter without one noticing what happened. This unit will also switches to battery inverter mode when grid voltage drops low or spikes high. The batteries are automatically recharged when the grid electricity comes back on.  Likely best deal on the market.  I believe Tripp Lite knows what they are doing when I study their line of products. They also make auto power supplies for medical use. 2014 Update: My Tripp Lite APS750 has been working flawlessly for 6 years in a humid beach climate. A Plus for burglar alarms or security cams: This APS works 24/7 as long as your batteries do.  This unit does cut off when battery voltage gets too low to protect your batteries from early death via excessive discharge.