Likewise — I have an RTC but no UPS on an RPi 3, and have zero problems with data loss or corruption due to power failures from a few seconds to several days in duration. The only issue is if the RPi is down for the 10-15 days that it takes the Davis logger’s memory to overflow.
Going back to the original question on this thread, the RTC should work just as easily with a Pi Zero as with a full-sized Raspberry Pi. IIRC the RTC module is about $4 so not a huge expense. -Les > On 19 Nov 2019, at 10:35, Andrew Milner <[email protected]> wrote: > > for what it is worth I do not use a UPS - and we get frequent power outages > here. I do use a usb hard drive though instead of the SD card on my rpi. > Weewx has always recovered the data from my current davis and my earlier > fineoffset without any issues, so i see no need for a ups. Anyways sometimes > our outages are for 3,4,5 hours so it is doubtful the ups would keep things > running anyway even if I had one. I do have an RTC installed to make sure > there are no hiccups in recovering the data from the station logger though!! > > > > On Tuesday, 19 November 2019 20:18:46 UTC+2, David VE3STI wrote: > Susan: Do you have a Davis system? The reason I ask is that, from my reading > of the comments over the last few years, this 'argument' between the RPi > starting up and the weather station hardware may be limited to the Davis > systems with their logging interface. Would you be willing to share your > coding/scripts/etc with the rest of us? Although I have added an RTC and a > UPS, I wish that my system was robust enough to reliably deal with power > interruptions without these additions. (The RTC and UPS cost more than the > RPi!) > > David > > On Mon, 18 Nov 2019 at 21:32, Susan Mackay <[email protected] <>> wrote: > I use an RPi Zero W for Weewx and Nginx as well. > I use systemd to manage it and have pre-requisites that the 'ntp.service' and > 'time-sync.service' have completed before it will start. > Susan > > On Monday, November 18, 2019 at 11:52:38 PM UTC+11, David VE3STI wrote: > The problems occur during the startup, before the RPi sets its clock from the > Internet, and appear to be issues with the RPi and the Davis equipment > disagreeing on the time and getting muddled. It has been the topic of much > discussion and you can read the gory details in the wiki. I won't go into the > details here. If you have a UPS and rarely reboot, it becomes almost a > non-issue. > > David > > -- > You received this message because you are subscribed to a topic in the Google > Groups "weewx-user" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/weewx-user/I5C5Wqvtw7c/unsubscribe > <https://groups.google.com/d/topic/weewx-user/I5C5Wqvtw7c/unsubscribe>. > To unsubscribe from this group and all its topics, send an email to > [email protected] <>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/weewx-user/c6136128-8d33-450f-84b0-e70e75c49330%40googlegroups.com > > <https://groups.google.com/d/msgid/weewx-user/c6136128-8d33-450f-84b0-e70e75c49330%40googlegroups.com?utm_medium=email&utm_source=footer>. > > -- > You received this message because you are subscribed to the Google Groups > "weewx-user" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/weewx-user/44bc2cd3-0c5d-45d1-8f6d-1913424916d0%40googlegroups.com > > <https://groups.google.com/d/msgid/weewx-user/44bc2cd3-0c5d-45d1-8f6d-1913424916d0%40googlegroups.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/D4715FFB-A16C-4D47-B9AC-9EBC7E095C7E%40gmail.com.
