Energy Products

Home Energy Gateway app bug

Is anyone else having an issue with the way the app calculates Energy Usage? My experience is that it seems to be off by a factor of two when calculating the Solar Energy produced in a given time period. It also has a problem calculating the Home Usage energy. I've swapped a few emails with Tesla tech support but pretty quiet in that department. The app reports it is version 1.49.0 but the Tesla webpage with the changelog states 1.50 and 1.50.1 are out there. Google Play Store only has the 1.49.0.

Comments

  • Depending on what inverters you have, some inverters have displays where you can check values. You could also check the instantaneous value from the electric meter against the app, during solar production while minimal house loads are running.
  • To answer your first question, no, no accuracy problems here.

    Is it possible that a CT on one of the two legs of the 240V is faulty? I guess it really depends on how Tesla is calculating current flow, i.e. each Hot leg to Neutral, then added together, or across both Hot legs. Having a factor of two in the error is mighty suspicious.
  • Well, the meters on the inverters show a total value almost exactly twice what the app reports for Solar Energy Usage. I have downloaded the data from within the app and the kW reported for each time interval seems correct. If you integrate those data for the Solar power you get a number almost exactly twice whatever the app reported for energy. Interestingly, do the same calculation on the grid power data and that number agrees with what the app reports. It's not clear to me where the data resides and where the calculations are done. If the Gateway hardware stores the data and calculates the results then that's where the trouble lies. I suspect the app may store the data but the calculation for energy is done on the app. Tech support says they have elevated the issue to Tier 2 (whatever that means). I'm still interested in what others actually see on the app and how those numbers compare with other data, such as inverter meter readings.
  • My Tesla app data is consistently 1-2% different than what's on the front of my inverter. I chalk that up to wire crosstalk in the CTs that feed the TEG data inputs. The CT-based measurements aren't revenue-grade, but the measuring circuits in the inverter are.

    I trust you're accounting for home usage directly from the solar production that never sees the utility meter? Home usage +plus+ what the utility meter reads going outbound (if overproducing) should agree with what the inverter says was produced for a given time period. If under-producing, the utility meter number should be treated as negative. The factor of two difference tells me that the above is not the case.

    In my experience, the numbers reported from the inverter to the little communications gateway box (via Zigbee RF) are significantly more accurate than what the TEG reports via the CTs. But then again, I have the luxury of a legacy Solar City system, where I can see data from three different reporting systems, the Tesla app, the MySolarCity website, and the SolarGuard website for comparison. They all (pretty much) agree.
  • Just want to make clear I'm referring to the energy (kWh) being reported by the app. My system has three SMA inverters monitored with two separate Wh meters in addition to the watt meters on each inverter. The sum of the inverter watt meters matches what the app shows in real time as Solar output in watts. The problem is that the solar output energy (kWh) reported by app for a given time period is half that which is reported by the sum of the two Wh meters on the inverters. I've reached out to the installer to see if there might be a wiring issue but I doubt that is the case since the wattage is being reported correctly.
  • Sounds like there might be a bit flipped somewhere in the monitoring software in the Tesla server, that's causing the kWh to not be added together before reporting. They may not have integrated the data from the three inverters correctly. I'd bet that if you can talk to someone at Tesla that has mean skills in the data-crunching side of things (an engineer and/or coder) this can be fixed in software, over the phone.
  • Key word in your post is "IF". Trying to get a dialog with Tesla has not been very successful. I have swapped a few emails with Tesla tech support and suggested exactly what you said. Let me talk to an engineer or code person! However, I think this might work out through my installer. I left then an email describing the issue and should hear back next. I'll be sure and post anything I learn,
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