Hi all, i’m trying to make a simple graph showing two lines
- one showing this weeks accumulated heat usage
- one showing past weeks accumulated heat usage
We already have this for solar energy
just a raph showing current total next to yesterday total
but for this we use a “total_energy_today” sensor.
For my heat consumption i only have a sensor with total value that keeps growing.
If i simply plot the data in a graph like this:
type: custom:apexcharts-card
graph_span: 7d
span:
start: week
header:
show: true
title: usage week
show_states: false
colorize_states: true
series:
- entity: sensor.smartgateways_kamstir_heat_energy
name: this week
float_precision: 3
type: line
- entity: sensor.smartgateways_kamstir_heat_energy
name: past week
offset: '-7d'
I then get two graphs but starting at the total value of the beginning of that week.
I want them both to start from zero and accumulate
(sorry, new user, so i can only post 1 image yet)
but what i want is for both of them to start at zero and show the growing total.
I tried using the “statistics” option, adding this to the series:
statistics:
type: sum
period: 5minute
align: start
but that doesn’t do what i want. it takes the sum from the first value in the DB not the first value of the requested series, so it doesn’t start at zero.
is there a way to create this kind of graph with this value that keeps growing?
is there for example a way to transform the data by substracting the first value of the series so each line starts at zero? if i hardcode that, i get the graph i want. but it has to be dynamic ofcourse.
- entity: sensor.smartgateways_kamstir_heat_energy
name: this week
float_precision: 3
type: line
transform: "return x - 5.771;"
- entity: sensor.smartgateways_kamstir_heat_energy
name: past week
float_precision: 3
offset: '-7d'
transform: "return x - 5.146;"
this is what i want 
Or is it only possible when i create a custom “weekly_total” sensor?