Well he is a licensed master electrician, so I trust he checked that.
And again, like my house and 100A service - what are the odds you will be continually drawing over 100A? Especially if you schedule charging in the wee hours of the morning.
You won’t continuously draw 100A. But there is the time when you need to take uncle Bill and aunt Sally to the airport for a 6AM flight and uncle Bill tries to make some toast before they leave while the car is charging.
So what? If you have 100 amp service, the car is probably on a 30 amp outlet, so 24 amp draw for the car, 12 amp for the toaster, you could still add a water heater, AC, and dryer before being in danger of tripping the main breaker.
I guess you could have a space heater plugged into every 15 amp circuit, plus the oven, etc,
You could let the car draw 40A from a 50A outlet if you knew that it would back off on those rare occasions when everything else is on at once.
Yep, the main thing is if after doing load calculations an electrician is willing to install another 50 amp outlet with only 100 amps of service. It’s designed to be over provisioned, but I don’t know the formulas.
I have a 100 amp subpanel, that is the oven, receptacles, and lights in the house, totalling 325 amps of circuits. For six years my car charged off that panel at 24 amps, I never once tripped the main breaker for the subpanel.
That isn’t a completely fair comparison to an older house, because my AC is on the main panel, and I have a gas dryer and gas water heater.
My house has 100A service, built about 20 years ago - electric dryer, oven, hot water tank, dishwasher and AC all off the main (only) panel. I added a 50A circuit to plug in the charger. (For flexibility, a NEMA 14-50 socket that the charger unit plugs into).
Uncle Bill’s toaster is maybe 1000W on 120V so pulls 8A. I suppose if I try I could get all of the big loads going at once, but considering this is a common setup for my neighbourhood and nobody complains about panel overload, “typical” vs “maximum” load is rarely an issue.
Someone built your house twenty years ago and supplied only 100 amps of service? I thought that more than that was standard today.
I thought the same thing. 100A seems really undersized. My 65 year old house was originally 100A. I have a hot tub, heat pump and EV so I have 200A now. The EV has a 60A fuse so I can charge at 48A.
Why? High draw items are - Dryer, oven, air conditioner, hot water tank… and now car charger. Kitchen has 20A outlets including dishwasher, rest are 15. I have 2 fridges and a freezer. It was built just before CFL (Compact Flourescent) lights, so actual draw for lighting is now less than anticipated. (I’m typically drawing 1200-1400Kwh/month, and during summer A/C peak around 2400Kwh.) AFAIK 100A is standard in the neighbourhood. (except for the really big homes - 2 stories, 3,000sf - that one guy has a monster cable for his Model X charger, I assume he’s using the max 80A charging)
Furnace is natural gas, as is the barbeque on the deck.
Other than the car charger, I’ve never made an effort to control what is used simultaneously or at what time.
It’s just that my parents’ house is roughly 65 years old and it has 100 amp service, so I thought that by now, higher amperage would be standard, given the new standards (microwave on separate circuit, for example).
It is a given when buying that first EV that you need an electrician. It seems like many people would be willing to spring for an extra $100 to get enough charging capacity to handle the maximum they would ever need. They would like to switch to a job with a longer commute without the need another electrician. It would be nice to be able to go a few days between nights when you need to plug in the car. You don’t want to worry about keeping the charged when it comes time to take the relatives to the local tourist stuff.
Technically, it seems quite possible for a reasonable cost and minimum bother. Electrical codes may need some updates.
Upgrading from 100 to 200amp service you talking about? That’s not just a hundred bucks. More like two thousand. Give or take.
24 amp would charge my Ioniq5 from 20% to full overnight easily. That’s about 250 miles of range. Really the times we need to charge with any time urgency at home have been never.
Instead of upgrading to 200A, I’m proposing something like adding sensing at or in the main breaker. Feeding that signal into the car’s charger would let it back off on what it’s pulling at times when other loads in the house are pulling a lot.
Speaking from experience within the last year - upgrading my home service from 100 to 200A ended up running around 8 grand. BUT - the panel in question was original to the house built in 1982, so needed an entirely new panel, new grounding, etc. to get it up to code.
Thankfully, that was part of my research when we were first planning to buy a BEV (and that 8k did include running an outlet to support level 2 charging in the most workable space!) and set us back a bit in our planning. It’s one of the reasons we’re currently a PHEV household and Level 1 charging is fine for our daily driving.
My understanding is that DC fast charging changes its draw based on the battery’s state of charge but that level 2 charging from an AC outlet is a straight flat draw until it shuts off. Back off would be turn off.
It would have to be a throttle at the EVSE level I’d think. And that is something that exists for apartments and condos, “dynamic load management”, software communicating wirelessly to various EVSEs sharing the amount of building capacity dedicated to EV charging, but I’d WAG making that work between rest of house and EVSE isn’t available nor likely cheap?
Until there’s a published standard on that sort of current sensing and management, and NEC buy-in, and industry buy-in, that whole ecosystem of smart consuming devices can’t come into existence.
As long as it’s the path of least resistance for each household to simply upgrade service, the demand for creating all this stuff will not materialize.
I’d sooner expect to see it take the form of utility-mandated whole house limiting for their infrastructure’s sake, than within-house or within-multi-family building limiting.
You’re 100% right its conceptually simple and seems like an easy win for enhanced safety in marginally provisioned legacy installations. That might well lead to the ability to under-provision new construction compared to the old dumb norm.
But the path dependency is strong. IMO it’ll be very hard to get from here to there, obvious though the advantages of there are.
I think you’re overthinking this. It is completely reasonable to plug the car in at the end of every day, and unplug it the first time you leave everyday. Even coiling the charging cable, this takes about 30 seconds. The car doesn’t care, your utility bill doesn’t care.
This way your car is at full range every morning, waiting for your relatives to suddenly demand chauffeur service.
If you need to run the electric furnace overnight, then let your car charge at 12 amps instead of 24. It will still be full by morning, and if it isn’t, the car doesn’t care. Unplugging at 72% instead of 80% does no harm to the battery.
I look at it the reverse. I spent $8k on a new panel, and the electrician just threw in a 200 amp main breaker, because it cost the same as a 150 amp breaker. I needed the new panel, I did not need additional power.
Sort of. It will back off above 95% SoC (or whatever). Of course, this depends on how much power you are providing. I can use the app to adjust how many amps the car is charging at, and do this dynamically as it is charging. For my Tesla gear, the EVSE power is set using switches, but it could just as easily be electronically controlled.
This already exists to regulate grid demand. Xcel, my electric provider, can control when my car charges by direct access to the Tesla API. I can login to my Tesla account and see that I’ve granted them permission to do this. If I had the desire to, I could access the same API and make the same charging adjustments with a properly composed curl command.
If I had a smart thermostat, Xcel could use the Nest (or Ecobee, etc.) API to control when my AC comes on.
My utility provided power meter is connected to my wifi, and I can read my instantaneous usage directly from it. Similar with my solar inverter.
All of the pieces exist to dynamically control my car charging. I don’t, because it doesn’t matter. Even when everything except the AC was running off 100 amps, it didn’t matter.
As I’ve mentioned, I can charge the car adequately to full between 12:30 and 8AM - technically to 80% unless I have a long drive ahead. Newer battery tech apparently does not degrade when constantly charged to 100%. This at 26A/240V without overloading my breaker.
Going a few nights between charging would be nice, but in reality it would mean that future fancy new battery tech to handle that would be used to put in the same 300-400mi battery and make the car smaller and lighter. There’s a sweet spot that gas tanks and batteries have, around 400 miles. That’s 4-5 hours driving between pit stops. 2½ is about my limit.
Very little in the house is a heavy draw - a microwave plugs into a standrad 15A outlet. My dishwasher uses a 20A outlet. Inly my dryer and stove use bigger outlets. (Gas furnace, and the AC and water heater are hard-wired).
Ideally there should be add-ons or new appliance with standard management capabilites from wifi, and it would be nice to monitor total draw, and control it. Unfortunately like many of the appliances also, my meter is fully stand-alone. I read the meter manually and phone it in every month to avoid estamted bills with surprise catch-up. There’s a lot of infrastructure that’s got to be upgraded. It’s a shame there’s not as much of a push as there should be.