Complex system advice needed

Emoncms Installation
1

Interested in expert advice for hardware needed for my quite complex system.

Components of system:

  1. Solar PV and batteries (Tesla PV and Powerwalls x 4). 3 Delta string inverters (8, 8, and 4kW) which are not currently monitored on a granular level.
  2. GSHP x 2 (Geocomfort 3 ton units - forced cold/hot air only)
  3. 2 load panels, one which has solar/battery input (this one is 400A). Both panels are fed by Tesla Gateway (limited to 200A).

Both load panels are next to each other in a closet with power and ethernet. Both GSHP are within 5 feet of each other in a utility room/crawl space. Solar inverters are on the outside of the house but feed a panel in the crawlspace.

Tesla app monitors total electrical consumption, pv production, and battery backup/usage (and does a very good job of that). My desire is to have more granular data on usage, especially the GSHP and ideally each individual solar inverter.

Questions for the experts:

  1. Should I try to “recreate” the monitoring I currently have with the Tesla Gateway with Emoncms (ie monitoring both panels, PV/battery input/output) or does it make more sense to just use Emoncms to monitor the individual circuits, GSHPs, and inverters separately?
  2. Related to #1, if I use Emoncms as a granular monitor is there a way to upload the data I’m already monitoring into Emoncms to have a “combined” dataset? I am currently uploading this data into pvoutput (sorry if this offends anyone!).
  3. Regarding GSHP monitoring, I would be happy with Level 2 monitoring. Can 1 EmonTx monitor 2 GSHPs or would I have to purchase 2 separate EmonTx units?
  4. I would love to have long term data from each Delta string inverter to be able to know when one is underperforming. Is there a way for a EmonTx unit (for example) to monitor output of each inverter separately (ie at the solar panel in the crawlspace)?

Apologies for my ignorance of Emoncms and electricity in general. Appreciate any insight!

2

Hello @homeontherocks

If you are able to extract the data you need from the equipment that you already have that’s usually a good approach. Are you able to adapt what you have to send data to pvoutput to also send to emoncms?
Can you extract the data from the Tesla Gateway via an API? I know some on here are getting data from Tesla API’s so it might be worth searching around if your not sure. E.g Getting data from my Tesla Powerwall

It sounds like these are near enough to make it possible to use the one emonTx. Is there a convenient point that you can get attach the CT sensors for each unit? I assume you will want to measure flow and return temperature for each unit, so a minimum of 4 temperature sensors. Are there any other temperatures that you wanted to measure? There’s a heat pump monitor guide for the emonTx4 here which may be useful: EmonTx4 Heatpump Monitor — OpenEnergyMonitor 0.0.1 documentation

3

Hi Trystan,

Thanks for the reply! I have the data uploaded to pvoutput right now and is working well. I have searched around but can’t find any real mature offerings to upload the data to emoncms. I’m not really experienced at python or programming but not sure where to start on this.

I agree with you that ideally I would be able to upload all the current Tesla data to emoncms then add individual circuit monitoring via EmonTx units (ie GSHP). Level 2 monitoring would be fine for my GSHP. The only other thing I would also like to monitor are the individual string inverters to be able to more accurately diagnose production issues with the panels and inverters but could also solve that with another EmonTx unit. I currently have the whole home data in 1) pvoutput, 2) local influxDB database with grafana (Powerwall-Dashboard/README.md at main · jasonacox/Powerwall-Dashboard · GitHub) and 3) Energy module in Home Assistant. If there were a straightforward way to get the data from either 3 of these to emoncms, then I could complete my monitoring with 2 EmonTx units (one for GSHP x 2 and one for inverter x 3).

4

Thanks, there must be a way to get the data from your influxDB grafana setup. Unfortunately Im not really familiar enough with either to be able to help but Im sure there are others here who may be able to give pointers

5

I’ve reached out to both the developer of that influxDB/grafana integration as well as the Home Assistant Energy Management integration community to see if there is an option for upload. Thanks!

Edit: The developer of the influxDB/grafana has already developed an integration that uploads to PVOutput here: Powerwall-Dashboard/tools/pvoutput at main · jasonacox/Powerwall-Dashboard · GitHub for those that are interested.

6

Regarding the 2 GSHPs, at a minimum I would want to monitor temperature in and temperature out for each, and I don’t see that a single EmonTx is capable of more than 3 temperature inputs. Ideally, I would also like to monitor desuperheater in and out, which would max out 2 emonRx.