Opposite of the "Daytime Dip"?


#1

I am seeing what I believe is a small dip at night after solar goes off. Has anyone else seen this?

Visually, I’d say it’s roughly 30% decrease after sunset on the mains display. If anything, I’d expect more power used at night due to oil heat furnace, but I see that coming on regularly at night (although not detected :frowning: ), but at smaller peaks.

My setup is a mains side solar connection. House usage should be the total mains minus solar production, but it seems wrong. I will try an experiment this coming week where I view a constant house usage with solar, then shutting off the solar and see if house usage changes.


#2

Got a screenshot?


#3

[quote=“NJHaley, post:2, topic:543, full:true”]
Got a screenshot?[/quote]
I had to wait for household to wake up to get a USB cord :slight_smile:

Here are 2 shots. March 18th after 2pm, household power usage was constant except for Oil Furnace. March 19th, it’s constant as no one is home as well.


#4

Ah, I see. I think I noted somewhere that there are several users that are seeing this, others are seeing the opposite, and some, like @sburque, aren’t seeing anything at all. Curious.


#5

Here is a better image with a cloudless day and no one home all day. It shows up very clearly… @HilarioAtSense


#6

If it weren’t erroneous, it’d be a pretty graph :wink:


#7

I have still been seeing the night time dip, but now I am getting 0 watts consumption at night at times! While I do aim to reduce my power, 0 just is not possible. I have roughly 100 night time watts after I go to bed (TV and computer off) plus furnace and refrigerator running at times.

So I have attached a view from yesterday and a zoomed in time at night where I am using 0 watts.


#8

Thanks for making us aware of this, Ira.

This seems related to this issue that Nick posted about: Solar customers: Recognizing the "Daytime dip" and how it might impact your Sense numbers.

As I said there: this is a known issue caused by miscalibrated solar CTs. The team is working to correct this and should have it fixed in the next couple of weeks without any action on your part. Sorry for the inconvenience!


#9

Here is a new view of my night time dip today on 4/14/2017 while I’m not at home this weekend and we got a nice clean, cloudless day graph.

Note that as Solar goes up, the consumption goes down slightly. I kind of wonder is if the slightly higher because of increased voltage when solar is backfeeding the grid.

Also, Sense had sent me an email and said they detected that one of my Mains CTs was not closed. As I have taken great care to make sure none of the CTs were pressed when panel was closed, I was sure this is not the case. Nevertheless, I checked it and they were fine and totally closed, and not in a position to be pressed. But just in case, I opened each and re-closed them. This is a result a day after this.


#10

I think that’s the classic daytime dip :slight_smile: also, that’s a productive system!


#11

[quote=“NJHaley, post:10, topic:543”]
I think that’s the classic daytime dip :slight_smile: also, that’s a productive system![/quote]

Oh my gosh, you’re right! It’s changed and I didn’t even notice!

But it is a nice picture of the daytime dip, though. Power is by 39 Sunpower 345w AC panels, 18 east, 3 south, 15 west. Surprisingly, each panel produces about the same total cumulative power each day, no matter which side they ere located.

The AC panels max power is 320w, despite being 345w panels, something I was never informed about, but see on the panel graphs, and buried in the specs. Anyone else considering them, may want less powerful panels.


#12

What in the wild world of sports - you flipped? Just by opening and closing your CTs, or did something else happen?

I had to look, we’ve got 28 LG 285w facing SSW, I think we max out around 240ish especially after it starts warming up around the first day of spring. The heat just kills production such that even though days are two hours longer on summer solstice, we get the same amount of daily kWh as the equinoxes.

Don’t tell APS, but we typically product about 50% or more over our consumption…bad math on our solar installer’s side, and we’ve really cut power use (partly with the help of Sense)…plus we’ve got a newborn who will be using her fair share soon.


#13

I don’t know. It’s hard to be sure, but it might have been after the update, or after me opening and closing the clamps (I did that just to the mains). I will look through the older days and see if I can find clear proof of when it flipped.

I will be watching to ascertain whether the heat affects the return. Since the inverters apparently max out at 320w, maybe that will probably be my limitation in the summer. Right now, East and west tend to max out just under 300w each and the South seems to max out out at 320w, which becomes a flat top of power for about 3 hours a day…

Here in Massachusetts, we get credit if we produce too much, and can transfer that credit to others (friends, neighbors, etc) as long as they are in the same “electrical district”, which is fairly large (about the size of a county). For my case, I can transfer credit to my son’s apartment. For you, once your newborn learns to switch on things (And forgets to turn things off), you will use those credits in no time! :grinning:


#14

Based upon looking at the Sense graphs, best as I can tell, the flip did seem to occur when the clamps were opened. But it’s hard to be sure, because of the noise of being home.


#15

Ah ha - but I’ve thought ahead :slight_smile: Every switch in the house is automated.

There’s still the extra loads of laundry, dishes, and probably longer water heater times to contend with, though.


#16

[quote=“miracj, post:14, topic:543”]
Based upon looking at the Sense graphs, best as I can tell, the flip did seem to occur when the clamps were opened[/quote]
Looking at the graphs more carefully, it does seem to indicate that after the clamps were opened it switched from night time dip to daytime dip., but I don’t know why that would be.

I’ll be interested if tech support indicates that the mains problem they said I had went away or not. Then the question comes whether the CT clamps can be closed completely, but somehow not working. Other CT clamps types actually snap close.

If this is the case, the daytime dip may have nothing to do with my night time dip, and now I am in the same place as everyone else.


#17

Two steps forward, one step back :slight_smile:


closed #18