Bug showing zero usage?

My monitor is running 1.35.3347 firmware. I keep noticing that my usage wattage is zero sometimes. App and web shows the same. I can open the meter and it will show zero usage the “now” dashboard shows shows a few usage bubbles, but calculates zero as a total. Anyone else having this issue?


I’m having a similar issue with my solar feeds, either it adds solar plus main and gives me a wonky number, or I get solar and it tells me mains are zero, like you show. I’ve been emailing tech support for a few weeks now, and they are no help, just say give us a day and then it’s working fine… really frustrating.

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I haven’t seen zero usage for a while. I’m guessing my calibration is off a bit. My inverter normally takes 5-10w to still be on/ keep WiFi active which normally reads-5w throughout the night. Now it bounces around quite a bit and shows it’s producing a few watts on/off during the night

There are 2 ways you can hookup Solar to the main panel:
line-side or load-side.
The majority of the setups use load side:
load-side-connection-diagram-for-pv-solar-systems-sense
In Blue the CT (current transformers) that measure current for the “mains”.
It is effectively what the meter is registering.
In Yellow the PV generated output from the inverter(s)

Suppose the PV is generating 500 watt
The blue CT’s measure 1000 watt from the grid toward the breaker panel.
That means that total usage is BLUE + YELLOW measurements added = 500+1000 = 1500 watt

Now with the other setup: line or supply side setup:
This is getting more and more popular because of larger solar systems being installed and not running into the so called 120% rule of the busbar (I won’t even try to explain it :wink: )
But this is how it looks:
line-or-supply-side-connection-diagram-for-pv-solar-systems_sense
In that case blue is measuring only the load from the house.
The yellow CT’s measure (like the other situation) PV generation.
Sense now needs to calculate the amount energy through the meter by subtracting:
1500 (blue) - 500 (yellow) = 1000 watt is being pulled from the grid.

So sense needs to know what your setup is in order to do the calculations right.
It doesn’t ask you if you have load-side or supply side setup when you set it up.
It somehow does some magic and figures it out by itself, and it is not always right.
I have installed multiple sense setups and often it has switched back & forth between the 2 possibilities.
After contacting support, they normally fixed that within the next business day or so.
I am not 100% sure this is this is the case in your setup, but it could be.
I can understand your frustration that no solution has been offered after weeks.
Maybe @JustinAtSense could take a look at this next week?

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I assume this is like the delayed auto-correct Sense does if the Main CTs are not oriented correctly. This presents some interesting questions regarding the (scalable & reliable) methods available to make things work as expected:

  • Is auto-correcting installation issues the best method?
    PRO: Not all users are electricians or comfortable with opening their panel and flipping/moving CTs so this method fixes things without that being necessary.
    CON: Manual intervention can confuse the auto-correct; delayed.

  • Is Supported modification scalable?

  • Do more install variations need to be documented and formalized by Sense to avoid the above? With that available, electricians can perhaps “get it right” at install time and/or end users know what to do without Supports intervention. They would also have the ability perhaps to call back an electrician and say “You didn’t install it right” without being billed.

Yeah I have been running a load-side with since Feb 2019. And if I remember correctly I started sense with no solar, then when I was adding solar… solar had to be actually producing something and during the calibration it had me turn on the inverter during the processes. I would assume this is when the sense meter detects load-side or line-side as far calculating if the solar production current is also going thru the main CTs for calculating usage. The solar CTs shown to the end user shouldn’t be changed in either setup… so a + value in solar CT at night would almost have to be a calibration issue.

The 120% rule is part of the NEC that says with solar production while in load-side setup (solar current is directly connected to the panel bar) you can add 20% more amps to you panel’s bus bar if that 20% is production… so a 200amp panel you can add up to 40 amps (9600w) to the bus bar and still meet code. Above (20%) 40amps and you have to connect you solar current to the line (between meter and main panel) aka line-side.

Before the NEC added this rule…you couldn’t add solar without adding the breakers together and having to stay below the bus bar rating.

The issue is the bus bar being rated at 200 amps and people have 160 coming in from the mains and then having 60 amps coming in from a back feed breaker (solar) then you have 220amps on your bus bar and no breaker flips.

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Yeah, I bought this new Solar ready panel recently, so my solar feeds in on the supply side. I get now what the support staff were toggling when they kept replying to my requests saying “we’ve changed something in the configuration, and now it’s working fine.” Unfortunately they never say which way they’re toggling, and I’m not clear what the expected values should be in Main and Solar feed.
Earlier today the monitors for Mains said ~900W, Solar ~10kW, but in reality I was pushing back ~9.1kW (-9.1kW). Does it ever show negative, or is the intent to show what’s actually being used?

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Usage will always be a positive number.
PV generation should during the day always be a positive number.
During darkness my inverters (i have both string & micro inverters in my setup) use about 13 watt power from the grid, showing -13 watt
Screenshot from 2022-03-05 19-41-07
So you will never see a graph from sense that shows how much power you pushed back into the grid.

That is where things like HomeAssistant come in handy

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What does it mean when usage is consistently negative numbers at night? The Sense power meter has always been wonky, it is significantly wonkier since I opened a support ticket last week.

This is real and not wonky behavior.
I have about 11.5KW of inverters hooked up and at night the inverters are drawing (in my case) 13 Watt over the period the sun isn’t shining from the grid.

It looks like mine started doing this on Jan 27th, 2022… never did it before. Not sure if there is somewhere I can see when an update came out. But mine is showing sometimes at night I am producing as much as 28 watts and it used to show -7w or so… meaning my inverter was using 7watts. It reporting that every night since Jan 27th that I’m still making power.