Home Vehicle Charging with lots of solar panels and net metering question.

[SDSean]

I figured I'd try asking this question here first since it is about my F150 Lighting.

When charging my lightning (up to 90%), I'm drawing roughly ~15KW. I have 41 solar panels that can max generate as much as about 12-13 KW but that of course is only at peak times. I average about 7-8KW over the course of the year. More than enough to "net out" and come out ahead in terms of billing, but not enough to charge my truck directly from just solar panels only.

(I'm aware of course that in theory I could turn down the charge rate in my app, though it's been debated a lot here whether that actually works or not, and besides it would also slow down my charging anyway).

So whenever I'm charging my truck, I'm pulling from the grid basically always, and according to my meter as noted that's ~15K. Here's my question. . .where does my solar power go in that case? Is it even getting used/somehow dropped? Is it still powering the other parts of the house, or is it just getting fed back down? I can see that if say I turn on my microwave while I'm charging my truck, the meter goes up to ~16K. But if this is during the day I'm still getting the suns rays but I don't see that applied on my meter really at all. According to my solar provider, once you go above the threshold for whatever your panels provide, you're pulling from the grid which makes sense to me but like I said. . . where does the power go that's still coming in after that mark has been hit? What am I missing? I'm pretty sure it's not a case of say solar bringing 7K, and grid bringing 15K b/c if that were true then the truck would show that's it's charging at a rate of 22K, which is not what's happening. . .

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[RickLightning]

You have no way to reduce the power the truck asks for. If you have the Ford Charge Station Pro, then you can set it to lower amperage in the app if you connected it.

No debate - no way to adjust the truck's demand.

 

[Maquis]

If you pair an Emporia EVSE with their energy monitor, it will automatically limit the charge rate to the excess solar being produced.

 

[K6CCC]

I have had solar with Net metering for about six years so I can answer that part. The truck really has zero impact on that - it's just another house load.

Whatever the solar is producing gets sent to your main panel. If the house load is larger than what the solar is producing, then some power is drawn from the utility. If the solar is producing more than the house load, then you feed some power back to the utility.

 

[SDSean]

I have had solar with Net metering for about six years so I can answer that part. The truck really has zero impact on that - it's just another house load.

Whatever the solar is producing gets sent to your main panel. If the house load is larger than what the solar is producing, then some power is drawn from the utility. If the solar is producing more than the house load, then you feed some power back to the utility.

Right but my question is if the solar is producing less than what I'm drawing (e.g. b/c the truck is charging), but is still producing where is that energy going? Like I said, when charging I can see that i'm drawing ~15K according to the meter and I know that's the rate the truck is charging at. . but if it's noon, i'm also making 9-10KW of power from the solar and I don't know what's happening to it. . .

 

[Tfarrell73]

My unity meter reads negative when I have excess solar production.

 

[Tfarrell73]

 

[K6CCC]

Right but my question is if the solar is producing less than what I'm drawing (e.g. b/c the truck is charging), but is still producing where is that energy going?

As I said, if the solar is producing less than the house load, than some of the house load is supplied by your utility. For example, if the solar is producing 6KW and the house load is 8KW, then your utility is supplying the remaining 2KW of load.

And again, the truck charging is irrelavent - it's simply a house load.

 

[SDSean]

As I said, if the solar is producing less than the house load, than some of the house load is supplied by your utility. For example, if the solar is producing 6KW and the house load is 8KW, then your utility is supplying the remaining 2KW of load.

And again, the truck charging is irrelavent - it's simply a house load.

What you're saying is what I thought would be true, but if that was true then my meter wouldn't be reading 15KW in from the grid at noon when I'm charging the truck. It should be reading something like 6-7KW in b/c I'm also generating solar right? Plus how would it be that my meter and the amount of energy coming into the truck read almost the same. . . This is why I'm confused the math doesn't add up. Or maybe it's just a limitation of the meter, showing me the total in from the grid b/c it's over the amount that's coming in from solar but that power is still coming in and used to feed at least the rest of the house.

 

[Scorpio3d]

I too have solar, but we technically do not have net metering but I do sell my excess energy back to the grid. I have the Ford charge station Pro and Tesla power wall three they are hooked up to separate breaker panels as I did not have 100 amp spare capacity in my existing breaker panel but I can calculate the excess energy that my panels are sending back to the grid and adjust my charge station Pro down to that level based on the Tesla app and the FordPass app.
So if I’m producing 11 kWh and my house is using 2 or 3 kWh I adjust the FCSP to around 40 Amps which pulls about 8 instead of 16 kWh, sometimes I do have to reset the FCSP when I want to go back up to full power i.e. 16 kWh
What EVSE are you using? does it have an app?
Does your solar inverter not have an app?

 

[SDSean]

No my solar inverter does not have it's own app. It's all SunRun, but I in effect have 2 systems b/c part of it was leased and part was not. I also have the Ford Charge station pro and the home integration kit to power the house if power goes out.

I certainly can adjust my FCSP, and am thinking about doing that (at the cost of slower charging) but since my net metering generally covers me anyway I don't think that's an issue. . .

I'm really just trying to figure out where the solar power goes when it is not enough to power all the load in the house. . . I thought it would be a net effect as mentioned but the math so far says otherwise, hence my confusion.

(I don't know what EVSE means. . . admitting that does make me feel a bit noob-ish ;-) )

 

[Scorpio3d]

EVSE = FCSP
Electric vehicle supply equipment= Ford charge station Pro

Your excess solar should be going back to the grid do you have a smart meter that you could pull up on the Internet?

 

[K6CCC]

Why are you trying to make this complex. Assuming you have one meter (as opposed to a separate meter for the EVSE), it's very simple math. House load (including the EVSE) - solar generation = utility meter load. If the math results in a negative number, you are feeding power to the utility. If the math results in a positive number, you are drawing power from the utility.

 

[SDSean]

I'm not making it complex. . . I'm simply telling you all what's happening.

It's noon in SoCal. I know that I'm "receiving" 10-13 KW from my 41 solar panels.
I plug in my truck to charge, which according to the Ford app is pulling in 15.6 KW.
My power meter also says I'm pulling in roughly 15.6 KW from the grid. . .

Where does the 10-13 KW from my solar panels go. . . ? To the ground? To heat? Partially back to the grid?

You're trying to tell me that it goes to the main panel and thereby into the truck, but I'm saying if that was true then the meter would not be reading -15KW and the meter could not possibly equal the same value as what the truck is charging at. . .

Yes it's all one meter I should add. . .

 

[Bushwood CC]

Does everyone have some form of off peak power? I have solar panels but almost all of that goes back to the grid. I charge at night for less than half of what I get paid for what was produced.

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