Sense install with Solar and POWERWALL2

#1

I have an upcoming installation of a pair of Powerwall2 storage units to add to my solar. Could anyone with powerwalls installed (or knowledge of a proper setup using powerwall) provide me with information on best placement of c/t’s in that configuration? I’m concerned that with 3 sources of power in the panel, Sense may get confused as to what is coming and what is going. My installation will be utilizing demand offset (using the powerwall as primary power during high cost peak hours). Any thoughts or insight would be greatly appreciated.

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#2

Hello Dwleckie,

I also use batteries for my evening power usage. which helps with my TOU period. My main system uses enphase inverters to feed my loads during the day these inverters feed a 240 volt circuit in my main circuit panel. For my night time consumption using batteries and another inverter. power is feed back to the circuit to power the loads. in both situations from solar generation and battery storage both feeds pass though one set of CT’s for sense (solar), The main load CT’s from Sense monitors the power coming from the utility and the loads. keep in mind after you add the additional wires through the solar CT’s you will need to re calibrate the solar CT’s. I’m not certain how your powerwall will connect to you main circuit panel, but this is how I connected mine. I worked with the sense team during the connection process so all was calibrated correctly. hope this will help you…

Jmorrow

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#3

@jmmorusa. Thanks for the explanation…I’m confused as to how you routed both solar and battery inverters through the solar C/T’s. Did you align the dual wires from inverters so that current flows were in the same direction when discharging? The powerwall charges and discharges through the same wiring. With that in mind, I believe that the Sense solar C/T’s will pick up the solar output from the panels (minus what is feeding batteries as it will be flowing the opposite direction) and work as normal during daylight and when battery (powerwalls) is discharging it will again show up on C/T’s as solar output on the power graph?

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#4

Hello,
My main panel is 100 amp 120/240 split phase. so my connection are on the AC output of the inverters . both systems. both systems are individual connected with a two pole 20 amp breaker in my circuit panel the AC connections are routed through the CT’S monitoring the solar. just make sure you connect on the same phase on both battery inverter and solar inverter going to you breakers. I am using two 20 amp 2 pole breakers for both systems. Without knowing much about you system I can assume that your connection would be similar to my connections.

Thank you,
Jeff

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#5

Hello,
Once you route your AC out are connected to you breakers just route through CT’s. Make sense technical team aware of the additional feeds going through your solar CT’s and re-calibrate CTs. Sense team will program on their end.

Jeff

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#6

@jmmorusa. Thank you - that is what I assumed. I am curious as to what the power meter displays during charging and discharging of battery. Could you share a screen shot? What I am trying to accomplish is “seeing” both solar and battery (of course minus the 10% or so loss for battery inefficiency) on the solar power meter waveform. If that sounds confusing, that’s because I am confused as to what it will look like. I know it’s crucial to have wires in C/T’s properly phased and flow direction properly oriented. My breakers for solar and battery are 60 amp as I have a 15kWH solar system and powerwalls are rated at about 13kWh each. Thanks for sharing and I look forward to a screenshot if you could do that.

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#7

Hello,
This is from this morning. My system is set to discharge from about when the main solar stop producing. Since I am on TOU, and my time of use period 2pm til about 8pm is the highest amount I will pay for electricity I discharge during this period. The batteries are charged from solar panels. I have 23 kWh of solar storage. My main solar system is 5000 watts.

Thank you,
Jeff

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#8

@jmmorusa. Thank you - a picture indeed is worth a thousand words. I can see from the screenshot when your batteries start picking up the load and stay active until your TOU ends at 10pm. Your help has been greatly appreciated.

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#9

Glad I could help…

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#10

I also have a two PowerWall installation and I use some of the energy stored in the PowerWall to power my home through the night. As a result, the Sense never “sees the sun go down” during installation and doesn’t complete its signal check.

When I installed the Sense I disabled both the PV array and batteries at the “turn inverter off” stage and re-enabled them at the “turn on” stage.

Shortly after reaching out to Sense technical support (excellent) I set the backup reserve on the PWs to 100%. I don’t know if it was technical support or the PW reserve action but the signal check completed and the Sense began identifying devices.

My configuration is shown below:

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#11

@tomstiller Thank you for the diagram. I am still waiting for the plans from Tesla that show how my system will be tied and had no idea of interconnects and panels that will be involved. I’m sure mine will be similar, but not the same as I have opted for whole home backup.

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#12

I had a whole home backup as well but the circuits for the cooktop and oven violated a local electrical code and Tesla had to return and install a new main panel.

The local code specified that a 230v device cannot use the ground as neutral (necessary if there are any 115 v sub-circuits) unless it is connected to the main panel. A whole house backup installation converts the original main panel into a sub-panel and so the violation.

The township inspector thought Tesla would just move the two circuits to the PowerWall gateway, which was now the main panel, but that box has no room for user breakers. The two remaining options were to rewire the house for the two devices or add a new main breaker panel. Tesla’s option was a new panel.

I was extremely pleased with the competence, workmanship and professionalism of the Tesla installers. If there is any blame for the original issue, it would have to fall on the site inspector who missed the two circuits during the inspection on the home breaker panel.

I wish you the best of luck with your install and hope it goes as well as mine has.

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#13

I have sent the information below to support as well, but thought I might seek user base input as well. @tomstiller provided excellent information, but as I thought, my installation is quite different.

I am preparing to have Powerwall2 backup installed at my residence. I have Sense/Solar installed and I need some clarification as to the placement of the C/T’s for the Powerwall revision.

What I would like to accomplish is to see my PV Solar and Powerwall OUTPUTS as a common item. With the C/T location for the solar C/T’s as indicated on the attached diagram, I anticipate that I will see the PV Solar output when active (minus whatever is going to charge the powerwall) on the standard power meter display on the app. When the Powerall is actively DISCHARGING (powering the home), I anticipate seeing the feed as SOLAR on the power meter. My total solar production should still be captured minus the powerwall efficiency loss? Are these statements correct?, and do you concur this is the proper C/T location for this purpose?

The Main C/T location as indicated on the diagram will function as normal EXCEPT when the BACKUP GATEWAY has disconnected my home from the grid during a power outage. At which point, the Powerwalls will be providing energy to my home. The question is: Will I still be able to detect devices with only using the Solar C/T’s? I am assuming that I still will see the Solar on the power meter in the app. Are these statements correct?, and do you concur this is the proper C/T location for this purpose?

I am trying to ensure that I have the proper locations as I will only have one shot at placing the C/T’s. Any guidance you can send my way is greatly appreciated.

Thank you

David Leckie

623.764.5872

dwleckie@cox.net

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#14

The C/T connection points you indicate will accomplish what you want. That’s the way I was originally connected.

One word of caution: during the Sense install procedure you will be asked to turn your inverter off. If you designate a portion of your Powerwall storage for daily use, the Sense will not really see the inverter as “off” because the PW will have picked up the load.

At that point in my install I opened the breaker shown just to the right of your solar C/T location, shutting off all solar supply.

Both C/Ts will fit nicely within the PW gateway but lead length and dress may be a problem depending on the physical location of the various load centers.

Good luck and happy Sensing and Powerwalling.

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#15

I think the CT location that @dwleckie indicates is probably the most sensible location if one wants to track the storage as well. However, if the battery storage is configured to accept energy from the utility, and not just charge from solar, then this configuration becomes slightly less desirable.

Also FYI David your home address is on the drawing. Some might recommend that you black that out when posting to an Internet forum. On the other hand, redactions seem to be getting people fired up this week :slight_smile:

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