Question: what is the ah of a 9v battery?
Answer: Lithium 9-volt batteries are consumer-replaceable, disposable high-energy-density batteries. In the PP3 size they are typically rated at 0.8-1.2Ah (e.g., >1.2Ah @ 900 ohms to 5.4V @ 23 °C for one type), about twice the capacity of alkaline batteries.