Energy logging, offline


Hope somebody can help me with this. We are doing a research project at work where we need to log energy usage. we need to logg 1 minute intervalls and for up to 8 weeks (due to that we don’t have access to it). The problem is that there is no wifi available where we are and would like to find a logger that is offline and can store the data locally. The readout of the logger could be wifi (cloud or local) with phone as a hot spot or Bluetooth. we are looking for something similar to shelly plug with a Schuko (typ f plug)

does anybody know a logger that can do this?

thank you

I have serious doubts if you will find devices which will log 1 minute intervals since it would kill storage on it quite fast due to almost continuous rolling of data. Most of wm-bus meters I saw and still remember have logging for past 12-months plus previous year. Maybe if you look closer you will find some devices which will have a log within 30 days. Anyhow, functionality you look for is usually done by data loggers which have proper flash storage.

How accurate does your data need to be? Do you need a “real” energy meter with calibrated values?
What energy values do you need? Active? Reactive? Forward? Reverse? 8 weeks can be possible on a smart meter, but it depends how many values you want to store.

So you can not set up your on local wifi network with an openHAB instance and for example a SonOff Pow R2?
You can also use a meter with e.g. modbus interface and read out with OpenHAB.

This forum is on openHAB so your question is somewhat off-placed here.
But why don’t you setup OH on a Pi Zero ?
Using openHABian, it’ll not directly write everything to SD but to RAM so ensure you complement that with a periodic copy to some safe medium, or switch off zram and use a largish commit parameter
(see Corrupt FileSystems every 2-3 month? - #20 by mstormi).

thank you everybody for your reply.

i know this is way off topic. but there is metering devices used in home automation so i was hoping that somebody knew of something that could work.

what we need to store is actually only active power and accuracy is somewhat important but i think that budget has to go first unfortunately. And we can not install anything, thats why i need plugs.

we have thought of a pi with openhab but because its about 15 different sites with 1-2 meters in each, things got complicated. (its for metering how people use light in their livingspace/appartments). if we would have gone the pi route we would also need to set up our own wifi-network.

have a feeling that we have to skip this for now and at a later stage go for a pi setup to log (and also for control).

/Thank you

Well you could setup a Shelly plug and a RPi it logs to via Wi-Fi - you can configure the RPi to be a WiFi AP so effectively setup your own two-device network.
And when it’s people to live in there, don’t they have a Wi-Fi you can use?

PS: If you only plug into where you can plug in, you won’t get the full picture: people will also use builtin lighting, won’t they. Sorry I don’t want to spoil your study design but I think the results may not be what you’re looking for then.

I’m just the assistant helping out with the stuff needed for this study. So I don’t know how the data is going to be interpreted but this is what they asked for and it should be enough for this study.

Can the pi be run as a access point? Cool didn’t know that. One other researcher did a study with wifi-connectet plugs and installed energy meter connected to the users WiFi and the network became very slow. Don’t know if it was that equipment (or a part of it )but now they are a bit cautious.

Ok once bitten twice shy but that was just bad luck. Lots of home automation users all over the world happily do this all day without that it takes their network down.
Maybe it was a bad product or badly setup (default password ?) and got attacked by some botnet, ultimately causing that slowness.

I’d deploy a Shelly and a RPi Zero w/ openHABian and log there. About 50 bucks. Put both of them into user’s Wi-Fi. When you have Internet that way, you can have the RPi be part of a VPN without a need to expose either the sensor or the RPi to the Internet.
Nonetheless you can login at any time and batch-copy data over. And you can access the openHAB instance and even use it to control things. Or add more sensors.

thank you. i’ll have a look at this. seems to be the easiest way.

thank you

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