I did a quick test for an hour (with my 4G mobile phone as a wifi hotspot) but hope to get confirmation from the community that this will work:
The Iotawatt device needs wifi in order to get it configured, but is it OK to remove the wifi after configuration of the clamps for about a month, then reconnect the wifi in order to export all measured data?
Is there any risk to not having complete registered data when wifi is not available during longer ‘measurement’ period?
I’m going to install the monitor at a large facility underground, where no wifi, nor 4G is available. So I plan to setup a hotspot without internet connection, just to be able to configure all clamps and leave it there for a month without any wifi connection.
I remember an issue with a customer long time ago with timing server on their network not being Google and therefor not working installation/measurement?
you don’t need wifi for the unit to run. Storage is all local.
Thanks for your reply, but besides the local storage on internal SD card, I have already encountered a TimeServer issue with customer that had their own TCS setup on their network and this blocked Iotawatt from correct functioning. So my question remains open…
Are you contemplating connecting to a local network w/o internet or not connecting at all?
As the location where I need to install 3 devices has no wifi nor 4G data signals, I could set-up a temporary wifi router, just to get the Iotawatt devices connected and be configured using my mobile phone on the same wifi router. But the Iotawatt device will indeed never connect to internet. What happens if I just power down the temporary wifi router after configuration? I know the status led will turn to red heartbeat, but what about the ‘normal’ working/data registering? Can I trust that once I get back to the devices after 1 month, that I can just use the graph or query api to extract the measured data?
Using this temporary wifi router, I am indeed NOT connecting to a local network (except the router).
What have you tried so far?
The system was originally designed to run without internet, but WiFi has since become a practical requirement. Internet is only needed to keep time accurate, as both the ESP8266 and onboard RTC drift—sometimes by a minute per day. With a time server, corrections are made hourly, preventing drift from growing into the 15–30 minute range over a month.
While more accurate RTCs exist, they are costly, not direct replacements, and still subject to drift. In practice, short outages rarely cause issues.
WiFi, however, is more critical. Most problems reported in recent years relate to WiFi connectivity or, less frequently, SD cards (the latter largely resolved). IoTaWatt recovers from power failures within seconds, but routers take longer to restart, sometimes leaving the unit disconnected. To address this, firmware includes fail-safe restarts: two minutes after a power failure if WiFi is absent, or every hour if no connection is established. These measures have significantly reduced user issues.
A system run without WiFi will restart hourly and accumulate clock drift. Removing these restarts would reintroduce old problems, so any option to disable them would be best left to advanced users modifying the open-source code.