dealing better with low battery: add a new battery state "yellow"

boddeke

i have noticed a couple times that i get a tado e-mail that a device needs new batteries but when i look at the app it will show a green battery icon and "good"

the cause is, i think:

during a cold night the batteries have lower capacity and the e-mail get sent. the app will also show a red icon when looked at right after the e-mail is received

later during the day the temperature of the batteries is high and they will nog show up as "red" in the app

eventually, a couple days later, the batteries will need to be replaced

suggestion: add an new battery state "yellow" in the app after it has been "red" once but looks good again (now "green")