That sounds good! I can see how that would save a lot of money on the bills. I especially like that you’ve got a “janky” template sensor haha. HA is so good for it’s openness and letting you bodge things together which have no right to work but do so all the same!
I’ll be taking advantage of the negative cost energy to charge my car. How have you got HA set up to take advantage? Is it automating certain appliances running when the rate is lowest?
I only have one at the moment. I bought a cheap Dell Wyse thin client from eBay, installed a light Linux distro on it and set it up as a Wyoming Satellite and as a snapcast client. That is connected to an old all in one mini HiFi for speakers. For the mic I just have a small omnidirectional USB mic plugged into the front. Biggest hassle setting it up was ALSA since snapcast and Wyoming were fighting over the devices
For me the car is the main thing that I can move to cheaper times. I’m also lucky in that I don’t need to do that many miles so I can often wait for cheaper times to charge. If I did more miles and needed to charge more frequently/consistently then it would probably be better to have a tariff with a set night rate, sometimes there are decently long stretches where the variable tariff doesn’t get as cheap as a night rate would be. On the other side there are days like this where I can get as much into the car as possible and get money back for it.
It definitely depends on your individual usage which would be better. If you’re with Octopus, I believe they have a tool which will show you what you would have paid on the variable tariff over the past months, obviously that wouldn’t take into account any behavioral changes you would make (or automate) if you had a variable tariff but could still be helpful.