recommended battery for 750 watt ups

It depends on the voltage of the battery. Use the following formula to calculate the voltage.

volt = watt / amp  

or

V = W / A

For a 750W UPS hooked up to a 175A battery, the battery would have to supply at least 4.3V, so either a 6V, 175A battery or a 12V, 175A battery would supply enough power to run a 750W UPS.