I have Lifeline gpl31xt 125AH AGMS in my setup. It is a sexy battery, very well made. They are expensive though, around $350 each but free shipping.
The charts at Lifeline show you will get about 1000 cycles for a 50% depth of discharge (DoD). Thus you have about 125AH available from a two battery system, which is 1500 watt-hr. Figure an inverter runs at 90% efficiency and you have available 1350 watt-hr.
You could run a hair dryer for 5 min at 1500 watts and use up 125 watt-hr. 5 min microwave would use up about 100 watt-hr.
So don't take a shower more than about 5 times a weekend and don't eat more than 6 tv dinners and you are good to go.
