Ask Siri how much battery charge is left on my iPad

My mum is blind and so uses Siri to do most things on her iPad. Before she updated her iPad to PadOS15.1 she was able to ask 'Hey Siri, what is the current charge on my iPad' and Siri would reply. However, since updating this no longer seems to work. I tried the same instruction on my iPhone (iOS15.1) and Siri replies with the current battery percentage.

Does anyone know what Siri needs to be asked to reply with the current battery % on an iPad?