Home Charging System / Charger Kit

[ajdelange]

I'm not sure I agree with the 800 pole Amps. IMO, it should be closer to 400.

No problem. Use 400 or any other number if you want to. But your load factor is 100%? That's really, really high.

To use 800, you'd have to make sure both side (H1 & H2 are balanced, AND your actual use is only at most 50% of the circuit breakers combined capacity).

Most people's load factor is way less than 50%, hence the doubling I suggested. My EVSE is in a 400 pole amp panel with 1360 pole amps of breakers in it. That is a factor of 3.4 times the panel capacity well over the factor of 2 I recommend and corresponds to a load factor of 29%. In fact, in the last year, my average draw from that panel was 3.37% of capacity. That's my real load factor. But my maximum draw (while charging the car) was 239 pole Amp which is 59.6% of that panel's rating.

Did the inspector arch an eyebrow at 3.4? Yes he did. So how was I able to get away with this? The answer is by being able to show the inspector what the nominal and peak loads on the panel actually are. I didn't even have to do that. The electrician just told the inspector "this guy measures everything" and as the panel was dripping with CT's he accepted this.

Does the Code allow for this?

The code is, IMO, pretty vague about how to size a panel. There are detailed requirements about so many VA per square foot and how many for an electric range etc. but when it comes to a welder outlet in the garage the guidance is less clear. Obviously while the welder could be on at the same time as the emergency heat in all the house's air handlers at the same time your Mrs. is using both electric ovens and drying laundry such an event is very very rare. My average load (for the whole house) is 4 % of the service. Given this in a complex situation (and modern houses are getting pretty complex) rather than a detailed load calculation the code permits submission of actual consumption data. Obviously there are considerations as to how you get this but ultimately it is the best way to go. An awful lot depends on the jurisdiction. In Virginia I got by with the 400 A service that was already installed because even though the factor for one panel was 3.4 time capacity most of the loads are not in use most of the time. In Quebec I was forced to upgrade to 600A service where half that proved to be plenty.

Maybe it does. I don't know. I just checked, and my home pannel has 320 A on one side and 300 A on the other; based on Circuit Beaker Capacity. So maybe it can be pushed further.

You didn't say what the main breaker was rated, Assuming it is 200 A you have 400 pole amp capacity and 620 pole amp installed. Installing a single 120 pole amp EVSE would get you to 740 which is under 800 so you should be able to do that. I don't know your local jurisdiction's policies but a local electrician will. In fact you might be able to install two EVSE for a total of 860. If the inspector balks (actually you want any balking done when you pull the permit - not after the work is complete and billable) you can try pointing out that of the 120 pole amps worth of breaker installed for each EVSE the unit will never draw more than 96 and that it can be set to limit its draw to less than that.

Perhaps if one can demonstrate the actual loads a Household will be using at maximum, to an Inspector, They will be okay with it.

Yes, that's the best way for sure. Check eGauge if interested in this approach.

Also, any 240V CB's will draw current on both H1 & H2 when in use, unless it is a Sub Panel; in which case you'd need to do a load balance on that as well.

Balance isn't that big a deal. As long as reasonable attention has been paid to distributing single pole loads you will be OK. Keep in mind that the dual pole loads are already, by their very nature, balanced.

At the end of the day, the goal is to not have your CB's ever trip, under use. So you have to ask yourself, what's the worst case (Max current) situation you'll likely have happen. Say you are Chrging the CT, running Microwave, Oven, other Kitchen appliances; Refrigerator and Freezer both kick on, and you are running lights ,TV and other devices; meanwhile you are running laundry, which also means the hot water Tank is on; What does this equal? Is it over 200 Amps thru either H1 or H2?

This is the kind of information that comes from an energy recording system. Here are some representative data from the past year for chez moi,

%iles: 50% > 2.67kW; 1% > 13.12kW; 0.1% > 20.64kW; 0.01% > 25.06kW; 0.0050% > 25.69kW; 0.001% > 27.41kW;

My service is 400 A (800 pole amps) so 1 kW represents about 1 % of the service. Note that my draw was less than 27.4 kW (28.5% of capacity) for 99.999% of the time but also note that 0.001% of a year is 5.3 minutes. The peak (1 minute average) demand for the year was 31.62 kW which represents 32.9% of service capacity,

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[ajdelange]

I may be in trouble... "Help me AJ Delange. You're my only hope" (200 amp box, 800+ phase amps already...)

Yes, you have a marginal situation there for sure. You are at the nominal level of comfort. To try to work within what you already have your best bet would be to install the load measuring equipment and send whoever goes to the permit office there with data showing that while your breaker based load factor is above the factor of two that eveyone seems comfortable with your actual load factor is well below that. Which it may or may not in fact be. The alternative is to get in an electrician and tell him that you want him to add 120 pole amperes ( 2 pole 60 A breaker) and see what he says. He should know whether he can get that past city hall or not. Adding more than 1 EVSE would be a challenge and not only from the potential load perspective. You would have to pull out a couple of those fat 15A breakers and replace them with slim tandems which is doable but only if the stabs in the panel support the tandems which not all do,

 

[ldjessee]

I am considering before the CT comes out upgrading my electrical service from 100amp to 200amp and having the electrical panel moved to the garage and have the current panel become a subpanel (so I do not have to rewire the whole house). My current panel is in the opposite end of the house in the basement from the garage and the previous owner wood panelled around and over (with a tight wood panel door) the current electrical panel.

If I do anything other than leave the current panel in, it will involve either cutting up the panelling or just relocating the panel.

I am hoping this would allow me to put in two 50amp circuits for EV chargers in the garage, with one on each side, but the one on the outside wall will be close to the garage door, so I could charge one outside and one inside. (too much junk in my garage to park both the Leaf and the Subaru, though I did prove to my wife we could do it if we emptied stuff out of the garage, but it would be such a tight fit; the CyberTruck would fit, but not with the Leaf, but CT does not need to live in the garage, it will be fine outside)

 

[ajdelange]

The new panel will have 200 pole ampere capacity (2 pole 100 A breaker), You should be able to install 400 pole amperes of breakers in that with no questions asked. Each EVSE served by a 60 A breaker represents 120 pole-amperes so you should could install up to three 3 of them with 40 pole amps left over. Or you could install 2 (240 pole amps) with 160 left over for say an 14-50R (100 pole amps) and some lights and 120 V outlets if you wanted to add them. Why limit yourself to 40 A charging (50A breakers) when clearly this additional service will support 48 for each of 3 EVSE?

By all means keep the old panel in place. The electrician will install new service equipment at the garage with two 100 A breakers, one for each panel. Run buried conduit to the old service entrance (the old panel). Thus the old panel does not become a sub panel. It just loses its status as the "service entrance" the main implication of which is that the bond between neutral and earth that is currently in that panel must be broken.

 

[TyPope]

Yes, you have a marginal situation there for sure. You are at the nominal level of comfort. To try to work within what you already have your best bet would be to install the load measuring equipment and send whoever goes to the permit office there with data showing that while your breaker based load factor is above the factor of two that eveyone seems comfortable with your actual load factor is well below that. Which it may or may not in fact be. The alternative is to get in an electrician and tell him that you want him to add 120 pole amperes ( 2 pole 60 A breaker) and see what he says. He should know whether he can get that past city hall or not. Adding more than 1 EVSE would be a challenge and not only from the potential load perspective. You would have to pull out a couple of those fat 15A breakers and replace them with slim tandems which is doable but only if the stabs in the panel support the tandems which not all do,

The house was built in 2004 so it's not THAT old of a panel. We did go to all LED lighting throughout (replaced 19 60 Watt bulbs with 7.2W LEDs on the first floor alone!). The 50 Amp double pole at the bottom right is a hottub. The Range has a 50 Amp breaker though we just installed a gas range and use a plug adapter to go from the 15-50 or whatever that plug would be down to a regular 110 outlet for the range to plug into (standard fare for making a switch to natural gas stoves).
I have space for a double pole down on the bottom left of the circuits. (Yes, they wired each room with a 15 amp light and 20 amp plug circuits which is probably WAY overkill)

What I would like to do is run a 100 AMP double breaker to a sub-panel in the garage where I'd run two Gen3 chargers. One for her and one for me. We can hot-swap chargers and just use a 40 Amp if need be but that's less than ideal.

What I CAN'T do is charge from the garage with a 110 outlet...

 

[ajdelange]

You may have some leeway then. For starters take 100 pole amps off your load for the no longer used range outlet. That's enough to accomodate 1 EVSE with 50 A breaker and you can probably argue for 60. Given you have dumped all the incandescents your best argument is probably through documentation of actual consumption. You can find that on your electric bill. Add up all the kWh for the year, multiply by 1000 to get watt hours, divide by 120 to get pole ampere hours and then by the number of hours in a year to get pole amperes., Compare that to your service. If it's only 20 - 30% of it I think you would have a pretty good argument for a couple of EVSE. Especially if you are willing to consider throttling them back a bit individually for now or collectively when the firmware becomes available (talking Tesla Gen 3 HPWC here).

Do you use the hot tub?

 

[TyPope]

Do you use the hot tub?

Not as often as we used the one we had in Albuquerque. We had the best patio there... Here, it tends to be too hot or too cold outside. But, I'm going to spend more time outside this year and less time in the house. So, it'll get more use. I've got it ready and the weather has gotten down to the 40s and 50s... not exactly screaming for us to get outside!

 

[ldjessee]

By all means keep the old panel in place. The electrician will install new service equipment at the garage with two 100 A breakers, one for each panel. Run buried conduit to the old service entrance (the old panel). Thus the old panel does not become a sub panel. It just loses its status as the "service entrance" the main implication of which is that the bond between neutral and earth that is currently in that panel must be broken.

Why cannot this panel be grounded to earth? afraid of some feedback or circuit created between the panels and the earth since they are 'close' (100+ feet apart).

Also not sure why I would need to bury the conduit. I would just run the conduit along the backside of the house (or inside in conduit if that would be better).

The house has an attached garage, with one end (the left rear corner from viewing from the front) has the current electrical service, while the far right is where the attached garage is. Basically a ranch style with walkout basement to the backyard.

 

[ajdelange]

The panel must be grounded but it must be grounded through the earthing circuit and that must be connected to the neutral (white) circuit at the service entrance and no where else. This is to prevent the earthing conductor from carrying any "objectionable current" which could raise its potential above ground.

You do not need to bury it. Sounds as if that might be a convenient way to run it and it gets it out of sight but if it's handier to run it along the house that's fine. The electrician is the guy that will figure out the best way to do it.

 

[ajdelange]

Not as often as we used the one we had in Albuquerque. We had the best patio there... Here, it tends to be too hot or too cold outside.

I thought that was the whole idea - to soak in the thing when the air temperature is below 0. Never saw the appeal and we finally took ours out thereby picking up 40 dual pole amps in the panel it was connected to.

 

[TyPope]

I thought that was the whole idea - to soak in the thing when the air temperature is below 0. Never saw the appeal and we finally took ours out thereby picking up 40 dual pole amps in the panel it was connected to.

yeah... I may eventually have to do that. But, I've got a couple of years before I have to do that. It IS nice to sit in the heat with a cold drink in hand and enjoy all your muscles relaxing.

 

[TyPope]

Add up all the kWh for the year, multiply by 1000 to get watt hours, divide by 120 to get pole ampere hours and then by the number of hours in a year to get pole amperes., Compare that to your service. If it's only 20 - 30% of it I think you would have a pretty good argument for a couple of EVSE. Especially if you are willing to consider throttling them back a bit individually for now or collectively when the firmware becomes available (talking Tesla Gen 3 HPWC here).

Do you use the hot tub?

687 kWh per year x 1000 = 687,000 Wh per year.
687,000 / 120 = 5725 pole ampere hours
5725 / (365 x 24) = 5725 / 8760 = .6535

If I did that right, I'm at 65% of my box's capacity. So, that's not that great.

****** BIG MISTAKE ******
Well, I'm embarrassed. I calculated using the average daily usage for each month rather than the total usage which made my numbers off by a factor of about 30. I've revised my math:

Here's the real number:

19,901 kWh per year x 1,000 = 19,901,000 Wh per year
19,901,000 / 120 = 165,841.66 pole ampere hours
165,841.66 / (365 x 24) = 18.93 pole amps
I have a 200 Amp x 2 pole service = 400 pole amps
My service is 48,000 W Which means my average load is 4.7325% of service.

And THAT seems more reasonable.

 

[ajdelange]

Something is funny here. Let's come at it from a slightly different direction.
687,000 Wh/(365*24) = 78.4 Watts average consumption. Your actual average consumption can't be that small. The average consumer in the US uses 914 kWh per month for an average consumption of 914,000/(30*24) = 1269 W average. So check that number. In the meantime lets use the average American annual consumption of 10,972 kWh per year.

1) 10,972 kWh * 1000 = 10,972,000 Wh
2) 10,972,000 / (24*365) = 1252.5W average draw
3)1252.5/120 = 10.437 pole amps
4)Your service entrance breaker size 200 Amps x 2 poles = 400 pole amps
4a)Service = 400*120 = 200*240 = 48kW = 48,000 W
5)Your average load factor 10.437/400 = 0.026 or 2.6%

Thus the Average American has lots of room if he has 200 A service. If he has 100 A service then his average load would be 5.2% of service. I'll note that my average load is 4.1%.

The rest of the story is peak loading and that gets a little trickier and where you might want to consider instrumenting to get solid information for your particular situation. I think it safe to assume that your pattern of loading wouldn't be too different from mine. I don't grow Mary Jane in the basement but I do heat with a W/W heat pump and I do charge a MX.

I have found that
50% of the time the draw is < 0.67 times the average
99% of the time the draw is < 3.3 times the average
99.9% of the time the draw is < 5.2 times the average
99.99% of the time the draw is < 6.3 times the average
99.999% of the time the draw is < 6.9 times the average
The maximum draw is 8 times the average.

Note that .001% of a year is a little over 5 minutes.

So if after you check on the kWh number and find your average load to be 3% you could WAG your peak load at 24%. Thus you'd have three quarters of 400 pole amperes i.e. 300 pole amperes left over for EVSA at 96 (0.8*120) apiece.

Whether you could ever explain that to a permitting authority, electrician or inspector I don't know which is why I keep saying it is best to have recorded numbers.






Av 4.1%
1%ile 13.7 %

Between Sat, Jun 1, 2019 00:00 and Fri, May 1, 2020 00:00 (335.00 days) Insolation: 1084.62 hr @ 1 kWh/m^2 ; Avg.: 3.24 per day
Most Sun: Tue, Jun 11, 2019: 98.25 kWh (7.06 hrs @ 1 kW/m^2); Peak: 13.33 kw = 95.73% of 13.92 kW on Thu, Apr 16, 2020 11:57
Energy consumed: 31872.9 kWh; Average power: 3.96kW; Solar: 15097.9 kWh = 47.37% of consumption; Imported: 16774.97 kWh
Max 1 min. consumption: 31.62 kW on Tue, Oct 22, 2019 16:43; Max 30 min. average demand: 24.04 kW on Tue, Oct 22, 2019 15:13
Demand (30 min max/average) factor: 11.5; Demand Charge: $94.73 (not billed). Exported 6168.9 kWh
Cons. %iles: 50% > 2.67kW; 1% > 13.12kW; 0.1% > 20.64kW; 0.01% > 25.06kW; 0.0050% > 25.69kW; 0.001% > 27.41kW;
Max 1 min.Brewery Panel: 28.63 kW (119.3 Amp.) on Tue, Oct 22, 2019 16:43; Estimated: Bill: $1845.25, Saved $1660.77
Tesla: 1216.1 kWh = 3.82% of total. Estimated $70.41, Per kWh: $0.0579; Per mile: $0.0193

 

[FN2187]

I currently have a Clipper Creek hcs 40 charger for a Nissan Leaf. I have 50 amp wire leading into it. Any need to upgrade for a CT?

 

[ldjessee]

I currently have a Clipper Creek hcs 40 charger for a Nissan Leaf. I have 50 amp wire leading into it. Any need to upgrade for a CT?

How far will you drive, on average, in a day?
That will determine if in an 8 to 12 hour period you can charge back your average daily use.