Wish to calculate remaining Wh from 2 batteries

Configuration
1

Hi,
What is the best way to create a new sensor that gives me the estimated Wh available from 2 installed batteries (totalled).

So far instance, both batteries give me these as available capacities:-
9905.28 + 9832.32 = 19737.60.

Thats what the batteries capacities are.

I also know that the capacity left in both batteries is 27% (ive added both together already in a separate template).

How can I get these pieces of information outputted to a new sensor giving me an estimate of how many Wh I have remaining?

I would do 19737.60 x 0.27 = 5329.15 but I’m unsure how to translate 27% from my created template to 0.27.

Thanks for any assistance, I’m relatively new to the power of templates.

2

Post your current code, then we can adjust that.
And also post the sensor outputs from developer tools, so we can see how the values is coming into HA.