Hi
I am a newbie for HA. but i manage to create my own dashboard . I want to get my offgrid battery output power but i have only V and A values. can some some explain to me how to calculate power?
You need kWh for the energy dashboard.
First you need to make a template sensor to get what, which means you need to multiple volt and ampere (W=V*A). (Template - Home Assistant)
The you need to make a new sensor from that sensor above that handle the measuring over time to get kWh.
HA has made an integration available for that. (Integration - Riemann sum integral - Home Assistant)