UPS Hat: Car Power Boot Up and Car Power Off Shutdown

Fully aware this isn’t necessarily the use case of the UPS Hat, but it seems so versatile it could be ideal for the job. Perhaps I’m just not steeped in the terms to know if it’s possible out of the box.

I was curious if the UPS Hat could be configured in such a way that it would power the Pi on when the 12 VDC from the car comes on? (is this the sleep functionality?)

I don’t know that this is necessarily the use case, but I was curious if it could be configured this way.

I understand that the UPS hat can clearly detect the absence of the car power and continue to provide power from a battery, so it can give the Pi a heads up to cleanly shut down.

Hi @thomas.dorr,
You can configure it as follows, though not exactly:

  • Go to Power Software → Configuration → Set Battery Percantage
  • For example, set the safe shutdown level to 90%.

When the car power is turned off, the battery level will drop 90% and the system will shut down safely.
When the car power is turned on, the battery charge level will rise to 95%(90%+) and the system will turn on automatically.

We’ll be adding this mod feature soon. :partying_face:
Thanks for your suggestion. :+1:

Sincerely.

I will order one in hopes that this feature is relatively easily integrated.

I do wonder how this will fare here (DLH, MN, USA) with our -40 degree winter temps, but that’s a different problem :slight_smile:

You know I suppose the power on is probably more of the puzzler… I was thinking about this… Maybe a timer of X seconds (10, 15 etc) with stable power and X % battery (50, 60, etc) … Could power on the Pi…

I assume there will be a way the Pi can see when the power is absent from the Hats input and begin it’s graceful shutdown after a software timer…

Many components above the HAT operate at -40 degrees, but normal 18650 batteries do not operate at this temperature.
These batteries work up to -20 degrees. For these conditions, different types of special batteries should be used.

We can see if there is power at the input of the HAT. It’s easy for us to add this feature.

Any word on getting this basic function working…

External power = Rpi power on
No External power = (any kind of safe) shutdown

Could someone explain why this doesn’t work? Or, without using the battery level solution how can I command a safe shutdown? Neither of those work in this use case.

For now, I run ‘watch python3 ./shutdown_on_battery.py’ which is just a script to read the power mode and create the shutdown event. It works, but regardless of the other settings, the Rpi does not come on unless the button is pressed.

S