That's all I use. I have one deep cycle marine battery and a smaller (motorcycle-sized) 55 Ah SLA battery. We use the small battery all the time for camping trips and stuff. It will run phones, radios, and a 12v fan or two for at least a couple of days. The big one will run even longer. I have a tiny 2 amp charger and a small solar panel, but if I had to, I could charge either from a car with jumper cables. I can't run the fridge or A/C but it does enough to get by and sleep in the heat. If things get really bad, we'll likely be too busy doing relief work to need much power at home.