Tempest voltage levels and power save modes, no rain detection etc

@jawoodfield - Before I comment more…Your timeline would be about right from a full charge to going offline without much opportunity for charging but have you monitored/looked at the timeseries data for the battery? Since your unit was brand new in the middle of winter, you don’t really have confirmation data that it had been charging properly (my unit ran all summer and fall, so I know it worked well in that regard). That may be something to investigate just to check that box of the potential list.

I haven’t found a solution in all my reading that I like. I have had my unit pop on twice since it first went offline (so assuming some good sunny days… it should charge… thus my unit doesn’t seem to be the issue… just my property). So far my thoughts from reading and monitoring the help community here have been:

  • Acknowledge that the unit wont work in the dark months (Nov-Feb) without something changing - this would be an expensive bummer and I like to think its not the solution.
  • Wait for the powerpak upgrade - sounds like it could be here before next winter.
  • Taking the unit down to charge with artificial light indoors - this is a chore … and I don’t want to bias my “climate record” or “calibrations” with indoor data or inconsistent siting information after install/reinstall (but if data points/ranges could be flagged by me as bad? i suppose that would be a small encouragement).
  • Run an extension cord to charge the unit outside with artificial light - i can do this… i think… my unit might be at the end of my extension cord length and I wouldn’t want to do it while its raining (which is pretty much all the time right now… and I would have to get my lamp up to 2+m high… oof maybe this isn’t it either) Perhaps this is a good task for a coming weekend?
  • Move my unit - other than lifting my unit up in the air more to perhaps increasing the exposure duration (an engineering task to set up guy lines and the like for any appreciable change). Unfortunately, I think my current sighting is optimal given my property - its in the center of my cleared land away from nearby obstructions/buildings (but not so far as to not have a wifi signal). I do have a barn that I’ve contemplated installing it on the top of… but it would be a trade off to some extent as it would be higher, but closer to the treeline and probably have its own microclimate due to roof heating and wind eddies and arg… I don’t have the bandwidth to do optimization tests for light levels around my property for what might only be 1-10% enhancement in light at the expense of other characteristics.

In the meantime, i have an old P/T/RH/WS Accurite sensor and a wealth of RH/T IOT type arduino sensors around to keep me busy and patient. Given the tech embedded in this sensor (i’m sure its neither trivial nor easy to manage the power) and in the backend systems, I still believe in the product and have faith that the unit will surpass any other consumer met package. The commentary on this page here makes me hopeful and the longer days do too… I’m guessing with no modifications, my unit should be up in a month or so.

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To avoid the data issue you could power off your hub then charge the Tempest until you think it is charged enough. Then just before putting the Tempest back on its mount power cycle it to clear out the data in its buffer and immediately mount it to avoid false rain then go in and power up the hub.

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It is unfortunate that you got your unit close to the shortest day in the year. Without sun the battery only goes down. Not a great first experience.
I totally agree, you shouldn’t need to charge using artificial light. I did write a post about it (Tempest charging with artificial light), but you shouldn’t be needing it. For me it was easy to do, as it was an extra unit I have, so it doesn’t matter when I bring it in. Currently I’m running an interesting experiment that might help some people to get through long stretches of dull (winter) weather. But of course it takes time, to get the different discharge curves. If that works great. Who knows it might get implemented. If not, the upcoming power booster should solve the problem.

Reaching the state where it only samples once every 5 minutes with the rain sensor and lightning sensor disabled is already something that IMHO shouldn’t happen. If your unit doesn’t get any good sunny days, it soon will shut down completely, waiting for better times. It should wake up by itself after receiving enough sun.

I’m now down to 3.5 volts here in southern England. Only just found out that the voltage was so low when rain was not detected. For me solar greater than 200W/m2 is needed to keep battery at a steady-state.


this number of 200W/m2 is probably the value reported by the tempest, isn’t it.
If so the charging very much depends on the season. In winter when the sun is very low and almost perpendicular to the solar panels, and parallel to the window that measures the solar radiation, the charging will start at a lower number than when the sun is high in the sky during summer.

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