> The homes' 200-amp panels don't have enough spare capacity to add a charger. (3 old less-efficient HVAC units, pool pumps, hot tub, electric oven, clothes dryer, etc.)

200 amp is a LOT. You will do just fine if you manage the loads, just install a smart charger that can monitor the overall power use and cut the charging rate if the capacity is getting low.

My house is on 125 amp service, and I have plenty of high-power consumers. It worked for me!

TechnologyConnections has a great video about it: https://youtu.be/CVLLNjSLJTQ?t=793

In most places I know of, you will not pass inspection for new circuits if you don't have a certain amount of headroom in your panel, this is defined in the building code, and there will be no way to argue your way past it.

The new NEC actually allows flexible loads. So check if your locality has adopted the 2021 (AFAIR) version of the NEC.

Share the dryer outlet with a Y splitter, $50. Just saved you $39,950. You will charge at 20-22 miles per hour, which is plenty.

A passive Y splitter is not a good idea, but you can get active ones with a switch that only lets one thing run at a time, which works just fine for EV charging.

$250 or thereabouts, currently on sale. Boom we saved him $39,750.

https://splitvolt.com/collections/all/products/splitvolt-nem...

Love it!

> So to add a charger, I have to get my home's service raised to 400 amps.

National Electrical Code 2020 says you can use a "power control system" (i.e. software) to ensure your busbar isn't overloaded (avoiding the service upgrade).

Related "smart panel" options to check out: Span, Lumen Smart Panel, Savant Power Systems

I've heard of people using this with 100A service to great success. So it should work very well with 200A.

That being said, code is code. So if the local codes won't allow the OP to use this, then they are still stuck.

How are you measuring your peak load? 200A is a lot. I could see getting a bit over 100A with all three ACs running simultaneously, but that leaves plenty left over for a normal L2 charger. Just time your charging so it's when you're sleeping, not cooking and doing laundry.

I only have one 5 ton AC, but I do have a pool, hot tub, and heavy draw electric appliances, and it takes some effort to clear 100A of simultaneous draw. Almost the only way to do it is to charge both my EVs simultaneously (and that's cheating, a bit, because the Tesla charger is pulling 48A all by itself).

Also, you could just dial it down, at 240V even 20A is quite sufficient for almost everyone.

> Just time your charging so it's when you're sleeping, not cooking and doing laundry.

But there's also passing inspection.

That's the problem - the city's inspection assumes full load from each of the appliances, plus some.

> But there's also passing inspection.

Why do you think that would fail inspection? A typical 200A panel has perhaps 400 amps of circuits on it. That's very normal. What primarily matters from a compliance/safety point of view is that the mains breaker is sized to protect the service wiring from overheating.

Quite a few homes are in that situation, especially because some cities have much older houses on average than Vegas.

I had to get a panel upgrade on my house that was built in the 1960s, in order to get a charger installed, despite the house being built with 220v circuits originally for the dryer and the kitchen appliances. Lucky for me I didn't need the power company to upgrade anything like a transformer. It was still pretty expensive though -- around $8k for everything. I get a small rebate for installing it but it doesn't come anywhere near close to covering the full cost.

And this was for a house, so it's easy. Nobody can tell me I can't do it, unlike the situation for people who live in condos and need their HOA to approve things. A lot of condos were not built with this kind of power in mind and will need upgrades, potentially trenching across the community parking lot, etc. The members of the HOA who don't own electric cars are not going to be happy about paying for other people's chargers so they aren't going to be helpful.

If we want people with average incomes to be able to afford EVs we will need to make it much cheaper to install chargers -- and we will need significantly better public charging infrastructure for people who live in apartments and need to park on the street.

Plus we are doubling down on electric power for everything, and our power grids are generally not great. In California we can barely satisfy existing demand, and rolling blackouts need to be implemented in the summer so PG&E doesn't burn down another forest. If we all had EVs on top of the current demand, the grid would not hold up. Given how incompetent our utility companies are at everything else they do, I'm not confident they will handle EV demand well.

Wow, sorry to hear that. I'm also in Vegas and have very similar loads (2x 5-ton, 1x 2.5ton, pool/spa, car charger, etc) -- but I luckily already had 300A service.

I agree with the some of the other comments; you absolutely can "get by" with 200A. FWIW, I rarely use 50% and my car charger can pull >=72A by itself ("dual onboard chargers").

I checked into smart panels just because I was interested, and that may be the way to go for you (Span wasn't serving this area at the time FWIW), but you may have other options that are still up to code. My garage had an extra unused "dryer" outlet even, prior to installing the dedicated charger, and I have another outlet in an exterior garage too (probably was originally installed for welding, I've never used it).

It's certainly doable as far as the physics go; how much hoop-jumping you'll need to do to pass an inspection though, is another question, but it might be less than you think.

I'm not sure what the inspection requirements are for the "isolated solar" idea, but I'd _guess_ that it's similarly cost prohibitive (not sure if the "NVE off-grid fees" would apply at existing residence or not), and you lose some of the benefits of solar -- net metering & pseudo-arbitrage of TOU rates + "balancing" panel/system load (mostly applicable if you do ESS), etc.

Feel free to reach out (email in profile); I'd enjoy hearing more about the situation & perhaps could provide some guidance or ideas. :)

200A?! Must be a single-phase thing.

Over here we have 3x25A (17kW) or 3x35A (24kW). You can easily charge a car at 7kW speeds without blowing a breaker. With a fancier load-balancing charger you can get all the way to 22kW, but very few cars can charge that fast from AC, most cap around 11kW.

200A in the US is 24kW.

Not an electrician, but why can’t you add a charger? If you don’t run ac and dryer and charge at the same time you should be fine? I also charged for 2 years just from standard outlet which had me nervous at times but made me a better planner. It cost me later $300 to add a charger(dryer outlet) which I think is quite cheap

This. I believe there are even smart management systems that can disable certain circuits when others are active e.g. if the hot tub, or dryer are on it turns off power the EV charger. IIRC they aren't cheap, but they also aren't 40k.

We have let the perfect become the enemy of the good. With the urgency of climate change, current grid infrastructure, and battery technology and production, the solution we needed to push hard was PHEV. For the battery in a single EV, it can build four PHEVs which means four households reducing most of their gas miles versus a single household. A common strawman is that a PHEV is more complex and harder to maintain. And yet that theoretical argument is directly countered by the existence of the Toyota Prius, one of the best for reliability, so good that it's used in taxi fleets. A PHEV is basically a Prius with a much larger battery. Another strawman is that there wouldn't be demand. And yet there is incredible demand for the Toyota RAV4 Prime. A PHEV with 40-50 miles EV range can be charged overnight with a simple 120V outlet, no expensive electrical upgrade required.

> For the battery in a single EV, it can build four PHEVs which means four households reducing most of their gas miles versus a single household

Is the adoption of new EVs being slowed by the lack of batteries? Building 4 PHEV with the same batteries as 1 EV doesn't mean you're going to sell four times as many PHEV.

A 40 mile PHEV covers average travel in EV mode range. You get 4 effective EVs for the battery of a short range (~200 mile) full EV with a substantially cheaper price.

Four PHEVs that draws down its batteries every day is far better than a single BEV that leaves most of its range untapped, given that batteries are expensive and require valuable resources.

Rich people buying luxury EVs as a third or fourth car is a huge waste as the VMT from those is wasted. EVs should be aimed at high VMT sectors like taxis to max their benefits.

yeah. World battery production has had to rise dramatically to even get EVs to where they are now. (and they contribute to EVs being about 10k more expensive than an equivalent gas car). A PHEV with 20-40 miles can get most of the environmental benefits of an EV without nearly as much of a weight penalty (especially since you can go the Toyota route to ditch the transmission) or cost.

>directly countered by the existence of the Toyota Prius,

The transmission design in the Prius is a lot more simple than a conventional automatic transmission. The engine is also so overbuilt that I've seen Prius engine swaps (sans hybrid system) into other Toyotas the basis of race engines. The 1.5L had forged crank and titanium conrod (very rare, even in sports cars), which could be pushed to 10,000RPMs with some valve springs.

We installed an Energy Management System (sometimes called Dynamic Charge Controller) in our last place - a townhouse with 90amp service - in order to be able to charge our Tesla Model 3. It was permitted and passed inspection with no trouble.

https://dccelectric.com/dcc-9/

Do you need a charger? Just a normal power point is fine for my Leaf usage.

It also has a setting to change slower if wanted.

Probably depends on your daily milage.

I don’t engage in long form discussion on HN anymore due to the moderation policy, I’ll say in short

1) You are in the process of being scammed. 200A is plenty to run an EV charger and 400A is absurd.

2) The max at home charge rate is 240v60A, 200+ amps extra is more than enough to peak charge three teslas at the same time.

Install a sub panel and 240v 60A outlet in your garage, then set your EV to charge around 11 or so. You’ll be done by 1-2am and never notice it.

Sounds like you could apply the money to more efficient HVAC with smaller circuits and avoid the $40k path.

Also, you can scale the EV charger to lower amps. I had trouble with tesla's gen 3 charger. I had a 60A circuit, which should allow charging up to 48 amps. But it would overheat sometimes and STOP charging. (bummer to come out to drive a car that hadn't been charged)

so I reduces charging rate from 48 to 40, then finally 30amps and it has been stable. And although I've parked with as low as 6% charge, I've never come out to a car that hadn't finished charging by morning.

That's a crazy amount of power, for reference here in France I run my whole house on a 9kW service (9kVA to be precise). That's with a heatpump and everything electric, including an electric car, and running the heating at more than 20°C during the winter. I might move it to three phases and 12kVA when we get a proper car charger installed, but with our solar panels and smart charging I think I might be able to save myself the trouble.

How are houses in the US made to be this inefficient? That's about one quarter of your installation if I'm doing the math correctly, (110V in the US right?)

It's Las Vegas. Has a pool and hot tub and, of course, air conditioners. You folks in Europe don't have air conditioners and mostly don't need them (except when you do you do and you suffer). This is not really representative of most of the U.S., but it is representative of a lot of the U.S. Basically everywhere in the South we have central air conditioning, though it's not that common to have hot tubs.

The previous poster actually has an air conditioner. You Americans don't usually understand that heat pump is for heating AND cooling.

I expect it's partly efficiency too. He already said he has inefficient AC. As I understand it dryers that just vent to the atmosphere are still common in America which is insane.

I think power is cheap enough in America that you don't care about wasting it.

Pool, hot tub, and uses air conditioning in Las Vegas...

Look, for better or for worse, Las Vegas is a testament to man's dominance of nature, and that takes a lot of electricity. It's not really about the efficiency.

Or as King of the Hill (TV Show) says of Phoenix: "This city should not exist. It is a monument to man's arrogance."

That was my impression as well. I'm in Poland, and 9kW is what you'd expect for an apartment or a small house. I needed 17kW for a small country house recently, but that's because of a "flow-through" water heater (no boiler tank) which makes sense in installations which aren't used every day.

A heat pump can heat/cool a small modern insulated wooden house with a 200W-450W power budget, throughout the year, with outside temperatures below freezing.

I installed an EV charger recently, with an 11kW of power allocation.

All that is way below the power in the installation mentioned…

US houses are incredibly inefficient.

I'm in Japan, and people even use less. 3-4kW is standard for a condo, 4-6kW is standard for a house, 10kW is max in general for a house with induction cooker and heat pump boiler tank.

We're not in Poland. Like I said in the post, I'm in the Nevada desert, in a 400 sq meter house, with a pool and a hot tub.

Here's a weather comparison to remind you that year-round, the highs in Krakow are lower than the LOWS in Vegas: https://weatherspark.com/compare/y/85104~2228/Comparison-of-...

I understand that. So include a 1.3x factor for cooling over heating (heat pumps are more efficient when heating than when cooling). That's still a far cry from the wattages/amperages mentioned.

"The Ecological Footprint for the United States is 8.1 gha per person (in 2018) and global biocapacity is 1.6 gha per person (in 2018). Therefore, we would need (8.1/ 1.6) = 5.1 Earths if everyone lived like Americans." -- https://www.overshootday.org/how-many-earths-or-countries-do...

France and Germany stand at around 3 earths...

The house is probably gigantic.

Houses in the US tend to be pretty large to begin with[1]. In newer cities that have a lot of land to expand into (entire new subdivisions in the suburbs), the average house is around 2500 feet^2 (~230 m^2).

But houses in the US also tend to only have one AC unit for the entire house. So if a house has three AC units, it is probably even larger than average. It could be 3000-4000 ft^2 (~275-375 m^2).

And naturally it takes a lot of energy to heat and cool all that space.

---

[1] https://www.propertyshark.com/Real-Estate-Reports/2016/09/08...

This is incredibly regional: in the south east ya, I guess you have lots of space and a not so great climate to deal with.

Houses on the west coast might just have heat pumps, maybe...and not even a central AC unit (instead, you get a separate heat pump unit for each room you want to heat/cool, our 2016 house has two units, but the first floor lacks any AC at all and only has small conductive heaters). Our electric bills are super low, however (mostly because...we don't need to really use heat all that much, and maybe AC a couple of weeks per year).

Not sure what your charging habits are but I fare well with a 10Amp, 240V wall plug to charge my car over night. Charging from 22:00 to 07:00 is sufficient to top up our day to day driving. We charge most nights and I can add about 20% over night. So maybe considering the time of use your whole load calc will look a little better?

People use clothes driers in Las Vegas? No wonder there is global warming.

I grew up in Arizona among the poor and working class and I can't recall even hearing of someone that didn't use a dryer

My home was built in the 1920s and I didn’t have any issues at all. Most neighbors with EVs also have chargers of some sort (similar age homes)

I find it hilarious that we are talking about preserving the environment and someone complains that they need would need more electric capacity to charge their vehicle and run their clothes dryer in the desert. As long as US exists, the world stands no chance.

You'd prefer he strung out a line in his backyard & hung all his clothes outside like they do in developing countries?

Yes of course? Not everything needs to go in an energy intensive dryer. It'll air dry just fine inside or outside

Oh no, he might look gasp _poor_ and lower neighborhood property values, thus cheating responsible savers out of their well-earned retirements.

Yes? I prefer to do that myself

I guess I'm from a -shithole- developing country myself, so can you explain to me how air-drying clothes is offensive to your sensibility?

(Again, in a desert; I can see how someone from Chicago might find it extremely convenient.)

Not offensive, just more labor intensive and uncommon in the US, especially for someone well-off enough to have his own pool.

The sheer sense of entitlement and superiority in this comment is astounding.

I will not even go into how drying clothes on a line is far kinder to clothes and makes them last longer.

Yes? Why would you not? It's a complete waste of money to use it if you don't need it.

I live in a place where you don't need a dryer for 80% of the year, and for 80% of the year I don't use the dryer despite owning one.

Just charge 120V. I honestly think a lot of people overthink this. 120V works fine, I also installed a transfer switch to switch between my charger and my clothes dryer.

You don’t need 400A service or any of that nonsense.