PV and EV charging

[zƬesla]

We’re about to have a PV array and 2 PowerWalls installed. We do not currently have an electric vehicle but can see us getting one down the road.

What additional equipment would typically be required for solar charging the EV? Ballpark costs?

And other than oversizing the PV, anything else we should do now in support of home charging an EV?

 

[getakey]

Depends on your rate structure whether you want to charge the EV from solar. In my case (CA PG&E), its better to charge from grid at off peak rates (11pm to 7am) and then have any excess solar credit to the grid during the day.

You will need a 220 charger, but wait until you get the EV to decide which charger.

 

[jboy210]

You will want sort of charger installed at home. Tesla has their own charger for around $500. Other EVs (and a Tesla) can be charged with a generic EV Charging Equipment. Price range from $250 on up. And you will need to get them installed with appropriate 240V circuit. I use a 240V 60A circuit to power my Tesla charger. Wiring costs depend on where you panel is located relative to your garage/parking spot.

 

[jrweiss98020]

When I had my PV installed, the installer included the EV charging circuit (240V 50A) to the garage, with a 14-50 outlet. That extra circuit required they also upgrade the panel from 100 to 200A.

Whether you install a 50A or 60A circuit is your choice. 50A is the max the Model 3 with the mobile charger and 14-50 adapter can handle. The Wall Charger can handle 60A, but that also costs $500 instead of $35 (plus the extra cost of the larger circuit)...

 

[zƬesla]

Thanks all. We’re in NH with net metering but no time-of-use/peak-rates. Basically we get some $ for everything we send to grid but it’s not 1:1, so better off using what we produce. Sounds like we should wait until buying the EV to figure this out. We’re getting a new 200A panel in basement for PW2s, so at worse, it may require new power cable from basement to garage.

 

[cwied]

If there's a chance you'll end up with a Tesla and you'll want to use the new Powerwall car charging control during power outages, make sure you have room for at least a 50 amp circuit on the backed-up side of the Powerwall Gateway. That way you can plug in during a power outage and have the car absorb any excess solar energy that would otherwise be wasted when the Powerwalls are full.

 

[SoundDaTrumpet]

Similar to @cwied, I have a 50A circuit backed-up by the Powerwall Gateway via backup load panel. I elected to have Tesla install the Tesla Wall Connector for $1600, non-backed up, which may sound expensive, but considering EV permit is $250, and they used 100A wire, it was a deal in my book. I installed the Clipper Creek 32A charger myself with permits, so I should know.

 

[bob_p]

When our 15.4 KW/4 PowerWall system was installed late last year, we kept our two Tesla Wall Connectors on the grid and added a 14-50 outlet to the house circuits powered by the solar panels and PowerWalls.

We don't plan to use the 14-50 outlet, except during an extended power outage, and only to add a few extra miles of range to our S or X.

Fully charging an EV takes a lot of power - our top priority was powering the house. Trying to charge our Tesla vehicles regularly off the solar panels & PowerWalls would have needed a much larger system.

Instead, we'll likely shift to a "free nights" plan soon - charging our vehicles overnight - and using the solar panels and PowerWalls to minimize grid usage during the days.

 

[zƬesla]

If there's a chance you'll end up with a Tesla and you'll want to use the new Powerwall car charging control during power outages, make sure you have room for at least a 50 amp circuit on the backed-up side of the Powerwall Gateway. That way you can plug in during a power outage and have the car absorb any excess solar energy that would otherwise be wasted when the Powerwalls are full.

Based on the diagram provided, looks like they're installing a new 200A panel with following breakers shown: 2x 30A for each PW, and 80A to the 100A PV meter. Is this what you mean, or on the old house panel that the gateway will also connect to?

 

[jboy210]

When our 15.4 KW/4 PowerWall system was installed late last year, we kept our two Tesla Wall Connectors on the grid and added a 14-50 outlet to the house circuits powered by the solar panels and PowerWalls.

We don't plan to use the 14-50 outlet, except during an extended power outage, and only to add a few extra miles of range to our S or X.

Fully charging an EV takes a lot of power - our top priority was powering the house. Trying to charge our Tesla vehicles regularly off the solar panels & PowerWalls would have needed a much larger system.

Instead, we'll likely shift to a "free nights" plan soon - charging our vehicles overnight - and using the solar panels and PowerWalls to minimize grid usage during the days.

free nights!! So jealous. Our off-peak rate is $0.20 and on peak is $0.40.

 

[bob_p]

Our current plan is $.091/KWh for all electricity.

The last time I checked, the "free nights" plan charges $.204/KWh between 9AM to 9PM and free from 9PM to 9AM.

 

[jboy210]

Our current plan is $.091/KWh for all electricity.

The last time I checked, the "free nights" plan charges $.204/KWh between 9AM to 9PM and free from 9PM to 9AM.

Our Summer rate is $0.40/kW M-F 4PM-9PM, $0.20 otherwise. But, with SolarGlass Roof and 2 PWs we have been 100% self-powered this week. I am starting care less and less about power rates.

 

[getakey]

I'm on an EV plan with PG&E. Below is from last year, might be higher now
Peak is $.53/kWh
Partial Peak is $.27/kWh
Off Peak is $.12/kWh

With PWs, I'm never paying Peak. Charge the EV on Off Peak

 

[Patrick66]

While they are there get the 14-50 outlet installed! It will make everything ccleaner and minimal added cost today. You might also want to plan for a third PW to make sure you can charge in an outage.

 

[zƬesla]

While they are there get the 14-50 outlet installed! It will make everything ccleaner and minimal added cost today. You might also want to plan for a third PW to make sure you can charge in an outage.

why wouldn’t I be able to charge with 2?

 

[jboy210]

why wouldn’t I be able to charge with 2?

It's a question of how big the charge reservoir is, how fast it gets refilled from solar, and issues with days were production is limited by weather, etc. With 2 you have 28KW max and you can might have 100KW battery. With 3 batteries you would have 42 kW max, so more excess to put in the car.

 

[power.saver]

It's a question of how big the charge reservoir is, how fast it gets refilled from solar, and issues with days were production is limited by weather, etc. With 2 you have 28KW max and you can might have 100KW battery. With 3 batteries you would have 42 kW max, so more excess to put in the car.

All units above should be kWh, not kW.

 

[eevee-fan]

free nights!! So jealous. Our off-peak rate is $0.20 and on peak is $0.40.

Your power price range justifies getting solar + powerwall. NV Energy Time of Use is 5-6 cents off-peak and 42 cents peak for Jun-Sep Mon-Fri only, so it's negative ROI for me to get rooftop solar. Powerwall also negative ROI too (if thinking of charging during off-peak to feed peak needs - but that's not allowed).

It's crazy how much PG&E charges for power while NV Energy (owned by Warren Buffet) can be profitable with such low power prices.

 

[jboy210]

All units above should be kWh, not kW.

Opps, sorry. You are correct.