Smart Solar Charging

[skiingj]

How does the Emporia Vue take into account Powerwall's? i.e. Does the Emporia know you have a Powerwall so you don't drain them?

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[ridgebackpilot]

How does the Emporia Vue take into account Powerwall's? i.e. Does the Emporia know you have a Powerwall so you don't drain them?

Good question. I don't think the Emporia Vue will know or care that the Powerwalls are powering the house. I assume you connect the Vue energy monitor only to the mains and the solar feed, not the feed from the Powerwalls. That way, the system will sense both solar production and energy consumption from the grid, and stop EV charging when solar production drops too low.

Fortunately, I can avoid all that by going one step farther and installing the Emporia Vue Utility Connect energy monitor. That unit connects to my PGE Smart Meter via WiFi and measures net energy metering. It will work with my Emporia EVSE to charge the vehicles only with surplus solar power whenever it's available. No wiring or sensors required!

 

[ridgebackpilot]

You're one of the lucky ones. Here we only get a fraction back, have to pay extra fees per month, upgrade to a 320A meter, and have to carry $300k liability insurance to get a grid connection.

That's crazy! $300K liability insurance just to connect to the grid?! Talk about a disincentive to install rooftop solar...

Here, PGE's biggest liability isn't rooftop solar but their old transformers and other infrastructure that tend to start wildfires in remote areas.

 

[skiingj]

Fortunately, I can avoid all that by going one step farther and installing the Emporia Vue Utility Connect energy monitor. That unit connects to my PGE Smart Meter via WiFi and measures net energy metering. It will work with my Emporia EVSE to charge the vehicles only with surplus solar power whenever it's available. No wiring or sensors required!

Thank you so much. The Emporia Vue Utility Connect wireless device would know the difference from solar or Powerwall? Not sure I can use it, waiting for my utility to comment on the smart meter having Zigbee/HAN.

 

[ridgebackpilot]

Thank you so much. The Emporia Vue Utility Connect wireless device would know the difference from solar or Powerwall? Not sure I can use it, waiting for my utility to comment on the smart meter having Zigbee/HAN.

The Vue Utility Connect only measures net energy metering. That is, it knows when your solar array is sending surplus energy back to the grid. When it senses that, the Emporia app tells the EVSE to charge your car instead using that surplus solar power.

Since your Powerwalls never send energy back to the grid, they're not involved in net energy metering. The only exception to that is Tesla's voluntary Virtual Power Plant program, which allows us to sell electricity back to PGE during grid emergencies at four times the normal rate.

With PGE, solar customers enrolled in net energy metering have to contact the utility and ask them to allow the Emporia Vue Utility Connect energy monitor to link via WiFi to their Smart Meter. Good luck and let us know what they tell you.

 

[skiingj]

The Vue Utility Connect only measures net energy metering. That is, it knows when your solar array is sending surplus energy back to the grid. When it senses that, the Emporia app tells the EVSE to charge your car instead using that surplus solar power.

Excellent. Thank you so much for the useful information!

 

[woody]

WOW!
You get 10X what I get

You'll need an EVSE that ramps charging speed to match solar output. That sounds like a good application for an Emporia EVSE and Vue energy monitor. The energy monitor will monitor the solar output and tell the EVSE to adjust charging speed to match the panel output in real time.

I'm curious if the variable charging rate will work with the Mach-E or if it will trigger a charge fault.

my wager is on the latter

 

[ridgebackpilot]

Not sure why a variable charging rate would trigger a charge fault?

Because of my electrical service, my current EVSE is derated to 40 amps rather than the 48 amps the MME can accept. Other chargers are rated for even less power. So we know the car is capable of AC charging at a range of amps.

Anyone with an Emporia charger care to comment whether variable charging rates cause a fault in the MME?

 

[Mach-Lee]

Not sure why a variable charging rate would trigger a charge fault?

Because the current charger module software is persnickety about some EVSEs if their pilot signals are not 100% consistent and in spec. Lot of people were having charge fault issues in the past couple months. 4.2.6 is supposed to help.

 

[woody]

WOW!
Only paid $0.047/kWh? You get 10X+ what I get for my solar generation (5mils/kWh but they only pay me for 80%* of the kWhs I send them, so actually only 4mils/kWh)

10.695kW array - provide more than we use, but not enough in winter
Not enough kWs(7-9kWs max.) most of the time for EVSE
One of our EVs charging at L1 directly from solar most of the daylight hours
~97/98% of charging L1
Basically only use EVSE to ensure it still works
battery is only 29kWhs for back-up
refuse to give control of EVSE to Xcel or enroll in any of their "programs" (no smart EVSE nonsense)

If Xcel paid us for our power generation (as yours does), our costs would be offset (unless TOU is charged, which will mean an increase of about 44% in winter [double in summer] ).

*in our six years of solar, Xcel has changed their billing/accounting six times for our account. Their current scam is TOU smart meters(in lieu of spending money on infrastructure) which they are threatening to install (you can opt out but you must pay "$12-$24"/month if you do).

 

[WI Mach e Fan]

I like others have 37 panels on my roof for a max of 11.4 KWh with a SolarEdge inverter. I have my inverter set to use excess solar energy, but it really doesn't matter when I charge since we are on Xcel net energy plan. They pay retail rate for any energy we produce that is more than we need.

Love the Mach-e

 

[markboris]

Not sure why a variable charging rate would trigger a charge fault?

Because of my electrical service, my current EVSE is derated to 40 amps rather than the 48 amps the MME can accept. Other chargers are rated for even less power. So we know the car is capable of AC charging at a range of amps.

Anyone with an Emporia charger care to comment whether variable charging rates cause a fault in the MME?

I posted earlier in this thread ( #5 ) that I use the Emporia EV charger and have the option "Excess Solar" enabled. The charger constantly varies the amperage in 1 amp increments from 6 to 48 amps. I have not seen any faults or issues on the MME with this variable charging rate in the 7 months I've been using this charger.

Edit:
As a side note, the EV charger needs to see a minimum of 1.4kW excess solar for 2 minutes before it starts charging the car.

 

[Maquis]

Because the current charger module software is persnickety about some EVSEs if their pilot signals are not 100% consistent and in spec. Lot of people were having charge fault issues in the past couple months. 4.2.6 is supposed to help.

I agree, the pilot signal needs to stay within spec, but we do have evidence that it can be done. Remember all the posts about FMCs throttling back the charge rate when the EVSE was (pretending to be) overheating?

 

[ridgebackpilot]

I like others have 37 panels on my roof for a max of 11.4 KWh with a SolarEdge inverter. I have my inverter set to use excess solar energy, but it really doesn't matter when I charge since we are on Xcel net energy plan. They pay retail rate for any energy we produce that is more than we need.

Love the Mach-e

That's great your power company pays you the same for excess solar power as they charge you for electrical energy you draw from the grid.

My utility (PGE) pays me retail rates for solar power used to offset the grid power I consume each month. But any excess solar energy I produce over what I consume each month is paid at the end of the year (net surplus compensation) at the paltry rate of $0.047/kWH, far below retail rates.

 

[MachEMaster]

I am lucky enough to have a power company that doesn't differentiate between time of day and power generated. I get essentially a one-for-one exchange with my local coop. What I cannot tell you is how much I've generated vs what I've used (I know I've generated more than I've used since months where I use more than I generate I still only pay the base load rate of 21/mo). Regardless of that, I charge my MMe only on the weekend since I seldom use more than 50% of the battery over the course of a week. I also have a Nissan Leaf and a Jeep Grand Cherokee 4xe that get charged almost daily. So far I have managed to keep my usage below what my solar array (~12kw) generates in a given day (assumes sunny weather). We are also in the process of adding a battery, but that hasn't happened yet. I can only hope that my coop doesn't decide to reduce my reimbursement rate anytime soon.

I have a Sense Home Energy Monitor installed. It has a good App, that shows how much Solar is generated, and how much you pulled from the grid. It also "learns" which loads are on in the house, so you can see real time when the hot water heater, toaster, basement light, etc. is on.

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