Would it be possible to take this one step further and produce a UPS?

I have a bank of 4x 100A Deep Cycle Lead Acid batteries and 2x 3000W 12V DC to 120V AC invertors.

I was hoping to put 2 batteries on each invertor and make some sort of charging system to go between the batteries and the invertors.

I would like to put a PIC with either RS232, RS485, USB or even LAN in the charger to interface with a computer and an LCD to display the current power source (either AC or the Batteries) as well as how much power (either battery capacity or time) is remaining to allow for safe shutdown of the computers.

I figured by using the AC invertors and a good 30A AC Power Supply might help make the project a bit easier. I would just have to make the interface between the power supply, batteries and invertor.

Any help pointing me in the right direction would be greatly apreciated.

Thanks.