How to add integer to a timestamp?

Configuration
,
1

I am using this template in a markdown card to see when my power meter battery was last changed and how much time is still remaining before i need to change it again:

<center>Battery last changed <b>{{((as_timestamp(now()) -
      as_timestamp(states("input_datetime.power_meter_battery_changed"))) /
      3600) | int }}h</b> ago on 
      {{as_timestamp(states("input_datetime.power_meter_battery_changed")) |
      timestamp_custom("<b>%A, %b %-d </b>at<b> %H:%m</b>")}}.<br/>Estimated<b>
      {{states("sensor.power_meter_battery_life_remaining")}}h</b>
      remaining</center>

all works great, I get this result:

Battery last changed **16h** ago on **Thursday, Sep 16** at **17:09** .
Estimated **244h** remaining

Now what I’m trying to do is to also include the time when the battery is about to run out, i.e. add the integer stored in sensor.power_meter_battery_life_remaining to now()… and no matter what I do I can’t get the types to line up, i.e. I get a str from as_timestamp() and I can’t figure out how to add the int (correctly multiplied…) in the sensor to it so that I can then translate the resulting timestamp to a date… any ideas? I also tried using timedelta, once again no luck with type match…

Thanks!

2 
{{ ((as_timestamp(states("sensor.power_meter_battery_life_remaining")) | int) + (now().timestamp() | int)) | timestamp_custom("%Y-%m-%d %H:%M) }}

I think that should do it.

3

unfortunately not…

{{as_timestamp(states("sensor.power_meter_battery_life_remaining")) }}

returns a “None”

4

Like your thinking

I wrote this

set the replacement date basic on percentage use and date it was replace.

5

Assuming sensor.power_meter_battery_life_remaining is in seconds, should plainly ve

{{  (states("sensor.power_meter_battery_life_remaining") | int) + (now().timestamp() | int)) | timestamp_custom("%Y-%m-%d %H:%M) }}
6

Ahh… of course.
That is hours, not a timestamp…

{{ ((states("sensor.power_meter_battery_life_remaining") | int *3600) + (now().timestamp() | int)) | timestamp_custom("%Y-%m-%d %H:%M) }}

The state is string of hours, so int it then multiply with 3600 to get seconds and add to now, then convert to date string.

7

That’s it! It didn’t occur to me to convert both to int and then just add them up… thanks.

Final config:

      <center>Battery last changed <b>{{((as_timestamp(now()) -
      as_timestamp(states("input_datetime.power_meter_battery_changed"))) /
      3600) | int }}h</b> ago on 
      {{as_timestamp(states("input_datetime.power_meter_battery_changed")) |
      timestamp_custom("<b>%A, %b %-d </b>at<b> %H:%m</b>")}}.<br/>Estimated<b>
      {{states("sensor.power_meter_battery_life_remaining")}}h</b>
      remaining until {{((states("sensor.power_meter_battery_life_remaining") | int * 3600) + (now().timestamp() | int)) | timestamp_custom("<b>%A, %b %-d</b> at <b>%H:%m</b>")}}</center>
8

Neat, unfortunately my use case doesn’t allow that, I am powering an ESP32 with two different power banks that deliver a constant voltage regardless of their battery level so the only thing I can use is knowing how long they last… fortunately they have a distinct enough voltage for me to check which one is connected and then use an input_number to determine the total lifetime of each one of them plus a helper that get’s reset to now() everytime the ESP restarts (after I confirm it via a actionable notification)

    power_meter_battery_life_remaining:
       friendly_name: "Power Meter Battery Life Remaining"
       unit_of_measurement: 'h'
       icon_template: "mdi:battery"
       value_template: "{% if states('sensor.power_meter_input_voltage') | float >= 4.97 %} {{states('input_number.battery_life_power_bank_11200') | int - ((as_timestamp(now()) - as_timestamp(state
s('input_datetime.power_meter_battery_changed'))) / 3600) | int }}{% else %} {{states('input_number.battery_life_power_bank_18650') | int- ((as_timestamp(now()) - as_timestamp(states('input_datetim
e.power_meter_battery_changed'))) / 3600) | int }}{%endif%}"