That's very nice. But a generator/UPS combo would be better as you can keep refueling the generator. Honda makes some nice generators. Hondas have a special inverter board that makes them work well with electronics/computers. Since you have a battery bank, you can use a regular generator though.
Yea, it makes sense for larger practices. A battery bank would be hard to justify for a solo provider especially since you see many on the board hesitant to spend more than $1,000 on a server.