Graphs of Utility Voltage for detecting issues


For a very long time I have been requesting graphs of utility voltage over time (say the same time scale and resolution as the current graphs), but Sense has not yet implemented this.

I want this feature in order to observe the power company grid fluctuations and be able to see as the “online tap changers” at my substation operate throughout the day.

This is a “power quality” monitoring feature.

The good news is that it is a trivial feature to implement (no complicated machine learning needed). The only trick is that it would require data storage and transfer similar to the current monitoring implemented today.

I just installed a brand new Sense unit today at a friends vacation home in the middle of nowhere that is at the end of the end of the end of the power grid. He is having power quality issues that are burning out electronics in his house (dryer circuit boards, etc…). We know the transformer is undersized for the 400a electrical service he has - we just need to prove it to the power company so they will come and upsize the transformer. So this is a pretty urgent need now! (where as at my house I want it mostly for trivia, this is a very real world need)

Obviously expansions on this feature could be alerts on power quality issues, etc…

This is a way to provide value from the Sense even without advanced device identification features.

POWER METER for Voltage

I agree with @eric2 comments. He makes valid points in his statement.


Here here! Up vote @eric2’s request. Sense is great, but it would be even better if it could ad the features requested. It will be great to keep the utility honest on their supply voltage.


I agree and want to upvote this feature. We had unbeknownst to us a faulty neutral line coming into the house. The only we we found out was the plumber got shocked doing work and sent out an electrician. Opening the sense app confirmed this.

I would expect that investing in a sense would be able to alert me to stick an easily detectable and potentialy dangerous situation.



I agree wholeheartedly, both with the desirability of this feature and the ease of implementation, this due to the fact that Sense is always aware of the incoming utility voltage. I’ve had this information for years as I have a 22,000 KVA UPS system from APC (Schneider) in my computer room. It’s insanely oversized, but I purchased the original back in 2001 on eBay. It was well used, but I bought a set of batteries and it was fine for years until 2016, when a battery cell shorted, causing excessive heat, which in turn caused the batteries to expand and more-or-less total the unit. When I contacted Schneider regarding parts availability, they told me to send the old one back for failure analysis, and they replaced it with a brand, new equivalent!

My logging interval is currently set at one hour, as you can see, but if I suspect voltage issues, I set it to one minute for a more detailed view. I mention this just to give Sense an example as to how this sort of information can be presented. An alternative could be a line on their existing continuous graph.


If we added every feature requested, Sense would be a very different product. Other features get prioritized for a variety of reasons. This is recommended reading for everyone in this sub-category: How to Submit a Feature Request. That said, we take feature requests seriously and have fulfilled quite a few of them and I can see this as quite useful.

For everybody - I’m curious about your thoughts on implementation. Would you like to see this as part of Data Export? As part of the Usage screen? As something under Settings > Sense Monitor (where you can see real-time voltage readings)? As threshold-based alerts? I’ll be sure to pass on the feedback.

I should also add that while some feature requests might seem trivial, they’re usually not once you get down to the actual implementation.


To answer your questions:

My primary use case for this is not as a data export. While that could be useful in some situations, I mainly just want the visualization if I had to choose one or the other. (though I could see the power company wanting an export to prove it to them)

I am not sure if we would want to overlay this on the usage screen necessarily since that may make it too complex, and the primary focus of Sense I think has been on utilization, so while I want a graph of the phase leg voltages, it should either be a separate graph, or perhaps something that could be toggled on or off along with the usage. (being able to look at voltage and consumption overlaid could be very insightful, but I also see the need to look at each separately)

I should call out that on the main usage graph, I really also want to see the two phase legs consumption able to be displayed as a stacked graph or something (maybe this is an “advanced” mode feature that could be toggled in settings). It would be really helpful in identifying some loads to see which phase leg they are on.

I very much dislike how buried the real time consumption and voltage data in Sense monitor is - it seems like making that more accessible in the app could be useful. I also think you should add a third reading in watts to the monitor: I want to see solar generation, total power flow out the electrical mains to/from the utility, plus values on each phase leg of the total power the house is consuming (so utility + solar). Power factor information (VA) might be interesting as well.

As to alerting, I would say the most critical would be around helping detect a loose neutral (or other sustained major voltage issue). So perhaps some upper and lower bound thresholds for each phase leg (probably could make them the same for both for simplicity?) that were defaulted to some reasonable levels. But let the user adjust perhaps since some folks may have really good or really bad power and want to modify the thresholds.

Then perhaps more advanced alerting would be around brief power quality events and extended issues. Things like short power blips (dropouts), overvoltages, actual outages, etc… It would be nice if Sense had some “ridethrough” ability in the hardware so it could stay online during brief issues (and still logging data about them). Then it would need to be able to queue that data up to send back to the “cloud” later assuming that often the Sense might lose its Internet connection briefly due to the issue. It may need to commit it to non volatile memory temporarily if its “ridethrough” ability was not long enough to make it through the issue. Some folks may want to be able to get a notification if their Sense unit becomes unreachable as this often will indicate a power outage.


Where is voltage reported? I don’t see it anywhere.

FWIW, the TP-LINK HS-110 Smart Plug reports voltage in its traffic, but I don’t see where it is exposed to the user.


The mains voltage data is buried in the Settings > Home > Sense Monitor screen.


Please consider adding a VOLTAGE METER that works just like the existing POWER METER, but for voltage only (L1 to L2).

The Voltage delivered from the power company varies greatly throughout the day, and I’d love to be able to track it. Furthermore, I have a 20KW solar array and want to be able to determine voltage drop between the meter and the micro inverters in the arrays. I’m already able to track/monitor the voltage each inverter sees, but I short of connecting a volt meter at the meter and write the down the values, I don’t have a way of plotting the voltage over time.

As you can see, my voltage fluctuates a lot, so determining how much is due to voltage drop (rise) vs. the voltage coming from the utility would be very helpful.


This would be great to have along with alerts you could set for high or low voltage. I know in the summer when the utility has voltage reductions there are times when I would want to take certain things off line to prevent overcurrents.


Yes, please add this feature. My Tesla Model S, set to charge at 40 Amps, will kick down to 30, when the Voltage drops below X, because it thinks something is wrong…

I’ve called my power company PP&L many times, they’ve even installed a meter on my meter with a resolution of a potato… according to them, my “Average” voltage (across… a week) was “just fine”…

I’d like to see real time, and historic, down to the second data of voltage.

When my wife gets a Tesla, I fear it will only get worse. We have a heat pump as well as electric dryer pulling power.

I’ve set my Tesla to 35 amps, and it has never kicked below that, but it’s frustrating when I should be charging at 40 amps, and do at other locations just fine. (NEMA 14/50 outlets).

…Also Sense doesn’t detect my Model S, which is 75% the reason I bought said Sense… a little disappointing there… When starting to charge the Tesla has a VERY distinct power draw.


Sense team, so how about it? Is this something you can add?


And, assuming you have a less than clean source of power (say a gas generator as I mentioned in another thread), probably tracking the frequency might be good too. Also, good for those who are totally off-grid, with battery backup (although I doubt there are many users who fall into this category).


Hi there, we appreciate your suggestion and will consider all of these ideas in the Product Wishlist for future product development. Unfortunately, we cannot say for sure at this time if and when this will be implemented, but we do thank you for your input.


@BenAtSense any idea if tracking voltage between L1 and L2 is in the cards this year?

This seems like a low hanging fruit to me, unlike device detection which seems to take one step forward and to steps backwards, perpetually.

Are all development efforts focused on device detection, or are there other teams/individuals focused on other enhancements as well?

Btw, thanks for the access to the beta web version. It seems quite stable, but alas, the 2 features that I really wanted it for (TRENDS and POWER METER) is missing. The focus seemed to have been, you guessed it, device detection and status.


Peter, we do have other teams focused on development outside of device detection, and are actively growing our teams so that we can tackle more improvements at a greater pace.

With regards to voltage tracking between L1 & L2, it is definitely a good idea and something we will consider adding in the future. We don’t have immediate plans to add this feature but have made note of your request. There are a lot of great features that we think will really improve the Sense experience, the challenge is having the time to tackle them all!

While the web app is still in beta, it is a priority for us. As I mentioned in another thread, the developer who was working on the web app is no longer at the company and that unfortunately means that additional web app developments are delayed until we find someone to pick up where they left off.


Sounds good Ben. Glad to hear development outside device detection is taking place!

I’m very impressed with the overall accuracy of my net usage compared to my POCO meter, which I get daily reports from as well (Delivered, Received and Net). The two track within 2% and most of the time within 1.4% percent!

Don’t get me wrong on device detection. That is certainly one of the main attractions of Sense, and I guess I’m pretty lucky in that I have 19 detected devices and 5 currently learning and another five that are “up next”. I haven’t had the time to validate all of them, but most of the detected devices have been consistent and show usage patterns.


It would be great or sense to do this for us but I don’t like to wait so I’m always looking for inexpensive ways to do things like this myself. I’ve been working a lot with esp8266 modules. You can create a pretty simple circuit to monitor voltage using an arduino, 9V AC to AC power adapter and an esp8266 to wirelessly transmit voltage. I like to use MQTT but you could write the data to a database and interface with it using a web browser.

Another option is to hack a kill-a-watt meter. Adafruit has a tweet-a-watt kit to wirelessly enable a kill-a-watt meter using xbee modules.

There are also many other projects on the internet that document various other ways to do the same thing.


Being able to see a voltage graph would be useful but I could also see a case for some machine learning along with it. It would be nice if Sense would give you an idea of your power quality, maybe compared with all users.

Recently I’ve had a bunch of AC/DC switching power supplies go out. Is it that they’re just cheap power supplies that died or have there been a lot of voltage related events that caused an early death? Do I have a lot of spikes that I should be installing surge suppression, or are there a lot of brown-out conditions so I should be complaining to the power company? If Sense could do some of that analysis that would be great!