what is ah?
In Europe and rest of the world, capacity of an battery is usually given at 10 hour basis. Some manufacturers give it at 20 hour basis in specific applications (e.g. Sonnenschein, Austria).
When you have battery of 10Ah in Europe it is always: 1A discharging current for 10 hours, end voltage 1,80V/cel, 20 degC ambient temperature ( not any other combination) if otherwise stated.
In USA ambient temperature (table value) is 25 degC and in Europe is 20 degC.
Always, one need to look at manufacturer's discharging tables and datasheets and see all combinations of parameters for given battery: temperature, end voltage, discharge current, time, ...).
In UPS applications end voltage is usually 1,60 V/cell.
In Solar applications capacity is given at 100 hour basis.
Regards for Greece from Serbia.