I use a Raspberry PI to run the WeeWX Weather Staion software.
The weather staion it is connected to is a Vantage Pro2.

The Pi as we all know does not have a real time clock and gets its
time from the network.

WeeWX sets the clock on the Vantage at startup.

WeeWX starts up before the network is up and if there has been a power
outage it sets the time wrong. The Pi then picks up the corrects time
and there is a conflict of times.

I could have written a delay into WeeWX but thought I would have go at
adding a RTC.

https://www.adafruit.com/product/3386

Is the one I got. Very simple to set up and get running.

When the RTC is installed, as per instructions, I wated till the correct
time had been picked up from the network and then I used
  sudo hwclock -w
to set the correct time on the RTC. I then uninstalled the Fake Hardware
Clock.

Now the questions!

1) Is there anyway to check the battery level on one of theses (I
suspect not)

2) I assume that the RTC will not be updated with the network time
automatically. If this is correct I will need to correct the drift. Is
there a way to check for drift or should I just used crontab to do a
regular sudo hwclock -w if so how often? Hourly, daily, weekly or monthly!

Thanks

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