Can a12v 10ah barttery be used in a ups that's supossed to use 12v 9ah battery?

Yes, a 12V 10Ah battery can be used in a UPS designed for a 12V 9Ah battery, as it has the same voltage and a higher capacity. This means it can provide power for a longer duration without overloading the UPS. However, ensure that the physical dimensions and connectors of the 10Ah battery fit the UPS properly. Always check the manufacturer's specifications to confirm compatibility.