EV Car Wiring

[mobiledynamics]

OT, but how many of ya'll have run wire for EV charging, just because the walls were open, etc.

I pulled 6 wire when I did some trenching, etc and they have raised the bar now to support 72 amps.

 

[kd3pc]

Placement of the outlet is often the issue, most want the outlet close to the service entrance...but the car may want the charger in the front (Leaf) or on the floor with an inductive charger you drive over.

Many EV owners don't realize the amps needed to support the fast/super chargers, so that you may need a heavy up or second panel.

What will the EV require and where? Is the question.

 

[tyme2par4]

I'm planning on it when I get around to upgrading my main panel. I currently have an overloaded 100A panel and a 50A sub panel next to it.
I'd like to upgrade to 200A main panel, and move the sub panel to the garage. That would accommodate a 240V circuit for my Volt, as well as the outlets and lights in the garage.

 

[69385vette]

I installed ChargePoint Level 2 charger in my shop for my leaf. Does a really fast charge compared to the 110V cord.

 

[nadogail]

I installed a 30 Amp, 240 Volt circuit for my son's Leaf.

Because we are on Time Of Use metering, on an electric car rate schedule, I added an analog electric water heater time switch.

All my son has to do is remember to plug in his car when he gets home, the time switch will start charging his car at midnight and shut off power to the car at 5:00 A.M.

He can over ride the timer by simply flipping the lever that sticks through the cover.

The circuit is straight forward; a 30 Amp two pole breaker in the main panel, 10 Gauge NM wire to the time switch, a 30 Amp two pole analog water heater time control, and 10 Gauge to the receptacle.

 

[Charles (in GA)]

I installed a 30 Amp, 240 Volt circuit for my son's Leaf.

Because we are on Time Of Use metering, on an electric car rate schedule, I added an analog electric water heater time switch.

All my son has to do is remember to plug in his car when he gets home, the time switch will start charging his car at midnight and shut off power to the car at 5:00 A.M.

He can over ride the timer by simply flipping the lever that sticks through the cover.

The circuit is straight forward; a 30 Amp two pole breaker in the main panel, 10 Gauge NM wire to the time switch, a 30 Amp two pole analog water heater time control, and 10 Gauge to the receptacle.

All of that is fine and well, but a EVSE is specifically required by NEC 625 to be considered a continuous load.

625.14 Rating. Electric vehicle supply equipment shall have
sufficient rating to supply the load served. For the purposes of
this article, electric vehicle charging loads shall be considered
to be continuous loads.

This dictates that a LEAF on a "30 amp" EVSE (and a 6.6Kw LEAF internal charger will draw 27.5 amps at 240v) needs to be protected with a 40 amp breaker and would thus use #8 or heavier wiring.

If you used #10 wire and a 30 amp breaker, then the EVSE needs to be setup to handshake with the car for the car to not draw more than 24 amps.

If the LEAF has a standard 3.3Kw internal charger, then you are OK. You can easily determine the difference as a standard 3.3Kw equipped car will not have the large Level 3 CHAdeMO fast charge inlet in the front next to the Level 2 inlet. If the car has a fast charger connection, then it has the 6.6Kw internal charger.



You can also tell the car to downgrade to a 24 amp or less level by going thru the setup buttons on the instrument panel.
EDIT: I looked at the manual and cannot find where you can force the charger to downgrade, also went thru the car menus and did not find it, I had never tried it and was thinking you could. I know my GE EVSE has a jumper that can be installed to down grade it to a lower max amps, a few brands have controls on the face of them to do that. The EVSE handshakes with the car and the car agrees to downgrade the charge level if needed.

The car will, of course, charge slower/take longer, at the lower amp/Kw.

Where I work, they recently installed ten Charge Point Level 2 stations, Previously I could not drive the LEAF to work (46 miles one way) and make it home, but now I can drive the LEAF and charge it for a couple of dollars, a bargain to keep from running up mileage on my other vehicles. However, the ones at work are powered by 208 (tapped off 460 three phase) and thus the car charges at a max of 5.75Kw, and takes measurably longer than my home units for the same battery percentage.

Charles

 

[ForceFed70]

I wouldn't install a circuit over 50amps.

Yes, some chargers will use more - and literally bake your batteries in the process. Charging that fast isn't good for them and should be reserved for public "charge stations" where you're sitting around bored waiting for the vehicle to charge. Otherwise, let it take hours to charge at home - you don't need to charge the damn thing in 30mins.

 

[Charles (in GA)]

I installed ChargePoint Level 2 charger in my shop for my leaf. Does a really fast charge compared to the 110V cord.

4.5+ times faster to be exact. Your 120v cord charged at 1440 watts, vs the 6600 watts of the Level 2 unit.

Charles

 

[Charles (in GA)]

I wouldn't install a circuit over 50amps.

Yes, some chargers will use more - and literally bake your batteries in the process. Charging that fast isn't good for them and should be reserved for public "charge stations" where you're sitting around bored waiting for the vehicle to charge. Otherwise, let it take hours to charge at home - you don't need to charge the damn thing in 60mins.

Totally depends on the battery capacity of the car. If you have a Tesla, then you want all you can get, as they have rather large battery packs.

The charger is internal to the car. The EVSE is simply a very intelligent switch and special cord that handshakes with the car to determine the max amps the EVSE is capable of supplying so the car will not draw more than the EVSE is capable of. You could install a 100 amp Level 2 unit (I'm exaggerating here, they don't make them yet) and a LEAF will still only draw what the internal charger is capable of, 6.6Kw. You cannot force feed the car with more amps than the charger is designed for. The car manufacturers size the internal chargers to the battery pack size, for a good match.

Also charging the battery heavily may not do as much, if any damage, as many think. There was a LEAF in England being used as a taxi and the guy drove it something like 100,000 miles, fast charging it every time it needed charging, and the battery had not degraded or lost any measurable capacity.

Charles

 

[ForceFed70]

Tesla tells you straight up - charge at full amperage all of the time and it will lower the life expectancy of the battery pack.

 

[Charles (in GA)]

Tesla tells you straight up - charge at full amperage all of the time and it will lower the life expectancy of the battery pack.

That may be, but "full rate" refers to using a Tesla supercharger unit, which is 480v powered and outputs up to 120Kw......

As I noted, charging any EV with Level 2 means it is charging with the car's own INTERNAL charger and that charger outputs to the battery no where near the levels of power that a Level 3 unit or a Tesla Super Charger can.

The link has some good info and comparison graphs in it.

https://www.tesla.com/supercharger

https://www.tesla.com/models-charging#/highpower

It doesn't matter how many amps of power you make available at the wall, the cars internal charger will only draw what it is designed to draw. No where close to a level that can cook the batteries.

Superchargers and Level 3 chargers (CHAdeMO and SAE COMBO) are EXTERNAL to the vehicle and charge the batteries directly.

Charles

 

[wssix99]

I have allowed for this and the thing to do now is easy. Run lots of conduit to all the places you might need it. Then pull the proper wire to the proper location when you get the charger.

The cars all have different ports and power requirements today and it's just going to get worse. You could cover all the bases today and then be behind the times one year from now. A large conduit and multiple open boxes will allow you to adapt as things change after you go beyond your first EV car, as well.

 

[mobiledynamics]

Don't know much about lipo, but I am well aware that not all batteries are the same.
For example, on high performance AGM batteries on the bigger sizes by Odyssey, North Star , etc - it's not uncommon that it will like and prefer 50 amp charge ...

 

[tyme2par4]

The cars all have different ports and power requirements today and it's just going to get worse.

That's not necessarily true. With the exception of Tesla, they all have J1772 charging ports. This is an industry standard now. Even Tesla supplies a J1772 adapter with their cars.
For the DC fast charging, there are 2 options, but that will never really be an option for residential use because your house wouldn't be able to handle the power required.

 

[wssix99]

That's not necessarily true. With the exception of Tesla, they all have J1772 charging ports. This is an industry standard now. Even Tesla supplies a J1772 adapter with their cars.

I shouldn't have said "ports." The cars all have different charging "options" and my intent was to point out that. On the back end where the wiring is in the wall, there are too many variables to commit solidly to the future with fixed copper wires. (Even charting stations with the same "port" have different amperage requirements.) IMO - Conduit is a must to locations where one might end up mounting a charting station.

 

[Norcal]

All of that is fine and well, but a EVSE is specifically required by NEC 625 to be considered a continuous load.

625.14 Rating. Electric vehicle supply equipment shall have
sufficient rating to supply the load served. For the purposes of
this article, electric vehicle charging loads shall be considered
to be continuous loads.

This dictates that a LEAF on a "30 amp" EVSE (and a 6.6Kw LEAF internal charger will draw 27.5 amps at 240v) needs to be protected with a 40 amp breaker and would thus use #8 or heavier wiring.

If you used #10 wire and a 30 amp breaker, then the EVSE needs to be setup to handshake with the car for the car to not draw more than 24 amps.

If the LEAF has a standard 3.3Kw internal charger, then you are OK. You can easily determine the difference as a standard 3.3Kw equipped car will not have the large Level 3 CHAdeMO fast charge inlet in the front next to the Level 2 inlet. If the car has a fast charger connection, then it has the 6.6Kw internal charger.



You can also tell the car to downgrade to a 24 amp or less level by going thru the setup buttons on the instrument panel.
EDIT: I looked at the manual and cannot find where you can force the charger to downgrade, also went thru the car menus and did not find it, I had never tried it and was thinking you could. I know my GE EVSE has a jumper that can be installed to down grade it to a lower max amps, a few brands have controls on the face of them to do that. The EVSE handshakes with the car and the car agrees to downgrade the charge level if needed.

The car will, of course, charge slower/take longer, at the lower amp/Kw.

Where I work, they recently installed ten Charge Point Level 2 stations, Previously I could not drive the LEAF to work (46 miles one way) and make it home, but now I can drive the LEAF and charge it for a couple of dollars, a bargain to keep from running up mileage on my other vehicles. However, the ones at work are powered by 208 (tapped off 460 three phase) and thus the car charges at a max of 5.75Kw, and takes measurably longer than my home units for the same battery percentage.

Charles

If it was tapped off 460 3 phase it would be 265 volts. But if 480 volts is availible then a transformer is required for 208Y/120V or 120/240V.