If you only have 3 pin, then you can simply change cells H7 to M7 from "=H4/7/$G$4" to "=H4/3/$G$4"
I might update it to have charge rate as a variable item.
Correct, you will need to add the standing charge. I have assumed they are all the same, but this is easy to add.
I might update it to have charge rate as a variable item.
Correct, you will need to add the standing charge. I have assumed they are all the same, but this is easy to add.