Noob Q: how to cast/template/? a device to a domain that Google Assistant can interact with?

I’m an absolute noob to HA, though I’ve used other home automation platforms.

I have an Enphase PV system with a storage battery. The Enphase integration is working fine and I have an automation set up to notify my phone when the battery’s state of charge reaches 95%.

I’d like to be able to ask Google Assistant what my battery’s current state of charge is. This value varies from 0 to 100 percent. But the battery’s SOC reading is not a domain/entitiy/type that Google Assistant supports.

I’d like to cast/template the battery SOC value to a domain that Google Assistant does support, like a sensor or dimmer, so I can ask my smart speakers “Hey Google, what’s my battery reading” or similar. Can someone please point me in the right direction? Thank you!