Advice on System Design for DC Loads

I have a potential client who wants to power a dc load using solar and batteries. He has access to utility power but only wants to use that as a backup source to charge the batteries if necessary. The load draws around 19A at 12V and needs to run for about 10 hours a night. I will eventually size the battery bank and solar array based on his location, but for now I'm concentrating on possible design approaches.

I've attached a simple block diagram of the first design that came to mind. It uses a solar charge controller, an AC battery charger, a relay to control when the battery charger needs to be turned on and off, and a relay to disconnect the load in the event the batteries don't have sufficient charge to power the load for whatever reason.

I've since though of a second approach using an inverter/charger setup similar to what is done in grid-tied solar electric systems with battery backup. Think Xantrex XW or Outback FX. But in this case nothing would be hooked up to the AC output of the inverter. One advantage of this approach would be the possibility of selling excess solar energy back during the summer months since the solar array will be sized based on the minimum solar insolation for the location.

I've already made clear to the client that solar and batteries will never be the most economical way to handle his load, particularly since he has utility power available.

I would appreciate any advice on the potential merits of the two approaches or any other approach you may think of.

Scott.