Offline data storage during internet outages

Hi, I have installed 2 Air units and will add their sky units to some very remote locations.

They are connected by a 4g network on one and a satellite connection on the other. The connections are powered by wind and solar but experience outages due to power supply and satellite conditions.

Is there a way to retain data on the hub for short periods when an internet connection does not exist and for it to fill in the data when the connection is re established?


Luuk Veltkamp
Par Avion

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David (@dsj) will need to reply as to specificly how much data is stored but this is built into the devices and the Hub.

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My understanding is that the Hubs shipped to all of the backers has internal memory to buffer data in case of a network connectivity problem. In addition (I just tested this last night), the sensor units will buffer data when they can’t talk to the hub and then send it when the connection is restored…

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For a Davis VP2 the amount of storage in the datalogger is a documented thing (typically, up to about a week of data for typical setups). What’s the corresponding number for the WF gear ?

Does the Hub have battery backup like the Davis console does ?

(can’t check mine because I haven’t received it yet - c’mon factory build build build!)

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No, but the Air and Sky do.

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Actually, the field test Hubs (which @GaryFunk has) do not store data because they were not built with external flash. The production Hubs, however, do have external flash.

So, both the end device (AIR & SKY) and the the Hub will store data when necessary in a first-in, first-out buffer. The AIR & SKY will store several hours of data if the Hub is without power or out of range. And the Hub will store several weeks of data if the Internet connection is down. Once the connection is restored, the data will backfill.

  • AIR will store about 2.5 hours of data (if it can’t reach the Hub)
  • SKY will store about 1.5 hours of data (if it can’t reach the Hub)
  • With one AIR & one SKY, Hub will store about 8 days of data (if it can’t reach the Internet)

I was answering the battery backup.

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Oops, I mis-read the question. @GaryFunk is correct: There is no built-in battery backup in the Hub. However, you can use any standard USB power brick to provide backup power to the Hub.


Ok, so there is no storage on the hub? I loose power at my remote site every night and there are gaps in the data.

What can I do as this is now useless to me :grimacing:


there are simple solutions to simple problems, put an external usb bank between you power and the hub, it’ll continue to power the hub for hours when you have a power outage (depending on size of the bank) and when power comes back, well it’ll charge the bank and power the hub till next power outage (choose a power device big enough so it can charge the bank and feed the hub simultaneously.

Hi, yes I have this in place already, the hub does not seem to store data when there is no internet connection regardless of being powered, how can I make it store data?


@eric - Most of those power banks shut off their output when connected to a charger, so they are useless as UPS-type devices. The industry is moving away from the older units that did pass-through power, because they overheat and also tax the limits of the incoming power to both drive a device and charge the battery at the same time. I have a growing collection of off-brand units that people claimed did pass-through power, and at this point could have saved money by just getting a desktop computer UPS in the first place.

As I side note (here we go again!), I just saw this on Amazon and it was tempting enough where I just clicked to order one:

Obviously only useful to those of us in North America with our wimpy 120 volt mains/wall power, with a footnote that some of the reviews hint that these may be old stock with stale batteries. (My weather shelf has two Raspberry Pi computers, a Davis Envoy, and the WF Hub…so this unit is almost purpose-built for my particular application.)

@luukveltkamp - Both the Air/Sky and Hub are supposed to buffer data during times of communications problems. If the Hub loses power, the Air/Sky will send their buffered data when power is restored to the Hub. If the Internet link drops, the Hub will store data until the link comes back up. There’s a post here detailing the buffer size, and I know that I have seen reports of it taking an hour or more for the data to back-fill on the WF site when a Hub is catching up following an Internet outage…

Thanks, I remember reading the post about buffer sizes before my sky arrived, but now I have 3 sky’s up and running around my business this is simply not happening, despite 100% up time for the hub, the data gaps still appear during internet down time.

What am I doing wrong?

There is a bug with the current firmware (v47) that causes the Hub to think it’s online when it’s not. This can result in what you’re seeing (holes in the data) under certain conditions. We have a new firmware build in testing right now that attempts to correct this issue.


My hub is firmware 49 and im definitely seeing massive gaps in my data. I’m having a issue with my air/sky going offline at the moment and coming back online intermittently and when looking at the graphs see massive gaps.
have a look at my station and check the graphs

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Hi @wavedr. This does not look like the “backfill” issue. Your Hub is online and has been for more than 5 days. Yet your AIR & SKY do not seem to be staying connected. Please open a ticket with support (email and someone will help you one-on-one.


Hi @dsj,
today I had a main power loss for few time. Then all returned online but not a wireless access point where HUB is connected to.
Station was offline for about 10 hours. When I came home I change connection access point and I reconnect my HUB. But I cannot see data but a big hole.
Does I lost today data? How much time is needed to HUB to fill data online after it return network connection?


Now, after few minutes, I see some data but original question remains: how much time to sync data online? When I can assume acquired data is loss?

Thank you… immagine

The Air and Sky can store short periods of outages (couple of hours). The hub can store longer periods (a few days) but to do that you need to have an UPS attached to the Hub to keep it powered up during those times when the electric goes off.

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I had a supply hole (few seconds) at 6:30 am, just the time to switch it off. From 6:30 am hub was powered. I don’t understand why I’ve a big hole until 5:00 PM. I fix the connection problem at 8PM and hub was powered (red light but powered).