Adjusting Sense Install w/ Existing Solar + New Tesla Solar w/ PowerWalls

Hi everyone

I’ve had a Sense monitor installed with my solar system for the last two years or so.

Tesla will be expanding this system with a new system and inverter along 2x PowerWalls.

I’d like to get inputs on how folks might incorporate Sense into this forthcoming installation. I do realize that Sense isn’t explicitly designed to support battery systems.

Here is my system design drawing from the design documents. Thinking of placing the Mains and Solar CTs at the red circles.

The way you intend to measure things, sense will never be able to measure loads directly. only calculate by substracting eg Z - 5 = load

I would think 3 & 5 would be more appropriate.
Would be interested in other reasoning.
Have you asked the support people from Sense for a suggestion?

No, I haven’t yet. I’ll have to do contact them.

Admittedly, I don’t really know exactly how the Sense hardware works. Though, I think that you propose is closer to what I currently have, 3 does seem like it would be more like ALL incoming power to the house, regardless of source.

Heard back from Sense support, they offered two suggestions

Option A: For each inverter system, there should be a feed for phase A and a feed for phase B of the panel. Group the A feeds from each system and place a solar sensor around them. Do the same for the B feeds with the other solar sensor. (See the illustration below:)

Doing this allows for Sense to monitor and isolate all of the incoming solar power so that it does not affect the usage readings. It is important that the sensors can remain fully closed around both sets.

Option B: Alternatively, if your multiple solar systems happen to feed into one subpanel, you may be able to account for these in a simpler way. You may consider installing the solar sensors onto the leads for that subpanel to capture all of the solar circuits feeding in at that point. See an example of that below:

( Important: If there are any live circuits for devices or appliances in this subpanel, their usage will subtract out of in-app solar readings throughout the day and night.)

I think that Option B is most like what @tomstiller original system looked like, as shown here

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That is a nothing saying answer.
They clearly did not understand your question.
You asked them where to put the CT’s.
They came back with an answer how to install the CT’s.
This could be a lack of knowledge though.

I would ask again if I were you.


Here’s the gateway panel so far - Tesla has said that their Neurio will be around the Solar Feeds and To Main Panel. Not sure if this offers any insight to folks.

I can’t give much more feedback except to say that you won’t get a full picture of energy flows with 3 sources (from grid, battery, solar) and 3 “loads” (house, battery, to grid), with just two pairs of CTs - you need 3 for a full picture. Long discussion of tradeoffs in this posting:

My 2c is that since your Neurio (formerly a Sense competitor, but gave up on detection) will be on to main and solar feed, you’ll want the Sense on to main and Backup feeds.

So it’s been about 4 weeks since Tesla installed my new solar and powerwalls, adjusting Sense in the process.

Here’s how they ended up doing it.

Things are working pretty well, although Sense doesn’t seem to agree with Tesla’s readings. Now, I realize that there’s no certain way to know who is more accurate, although I can say that Tesla’s solar production amounts are pretty much spot on with what my SolarEdge inverter is reading (Note: new solar no PTO yet, so reading only existing solar).

I am “struggling” to understand why Sense might be reading differently; for instance, here is Sense today

Meanwhile, here is some Tesla data

Solar Production - 25.3 kWh (1.0 kWh => PW)
Home Usage - 9.6 kWh
To Grid - 19.4 kWh
From Grid - 4.8 kWh

Specifically, I find it somewhat odd that some reasons are spot-on (like To Grid) while others like Production and Usage are off by more than 1 kWh or more?

Any thoughts?

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One thing that I noticed when thinking about how Sense’s Solar Production total is less than Tesla/SolarEdge.

I often have a negative solar production amount, I can’t recall if I had it before with certainty but wondering if the negative is getting totalized, thus reducing the sum?

Though, that wouldn’t explain why my Usage is off as well?