Continuing the discussion from Installing EV charging for one unit in a 6-unit condo building:
It seems like it should be possible to add sensing for the current through the main breaker. With that the load that the car is pulling could be reduced only when necessary. It would add a little to the cost of the control system but not that much. It would not require additional power components.
You would need have a smart charging dock to do this. There are a few that have that capability but I am not qualified to recommend one. You can also program them to only operate during times of day when there typically isn’t much of an additonal load like in the middle of the night.
That is what you can do now as a work-around with what is currently available. If someone were to make a charger with that additional sensing of main current, it could, for example, reduce what goes into the car when the refrigerator is running.
While it’s certainly possible to add current sensing into the mix to allow higher amperage charging, it probably isn’t actually necessary outside of edge cases. For example, if we assume an EV efficiency of 3 miles/KWh and charging 10h/day, you get something like this:
| V | A | KW | M/10h | M/Y |
|---|---|---|---|---|
| 120 | 15 | 1.44 | 43.2 | 15768 |
| 120 | 20 | 1.92 | 57.6 | 21024 |
| 240 | 20 | 3.84 | 115.2 | 42048 |
| 240 | 30 | 5.76 | 172.8 | 63072 |
| 240 | 40 | 7.68 | 230.4 | 84096 |
| 240 | 50 | 9.6 | 288 | 105120 |
Even a pain vanilla wall socket will get you past the average annual mileage in the US. Sure, if you drive a Silverado EV 200m per day you’re going to need a big charger. But for most people, a 30A dryer socket would be adequate to keep 3 EVs charged on rotation even on relatively pessimistic assumptions of total charging time used and total mileage required.
So much of what we have is legacy hardware not configured for smart control. Not only did I dial back the amount my car charges (from 40A to 26A) but I also tell it to charge starting at 12:30Am - when usually, the dryer, dishwasher, oven, and many of the lights in the house are off. And often, the air conditioner and hot water tank are not needing to run.
But there are a number of devices in the house - fridge, freezer, A/C, hot water tank, furnace, etc. -that randomly turn on and could benefit from monitoring and oversight. I have a NEST thermostat for the furnace/AC. There are no devices I’m aware of that would coordinate multiple such devices for efficiency.
For example, where electricity includes peak demand metering and variable pricing, to run the big freezer to colder than normal so it does not need to run again while dinnertime cooking increases electricity use. Same with the hot water tank - can we overheat it or tolerate cooler hot water until other devices (oven, microwave) are no longer in use? A smart computer could also exercise judgement and dial back one or another so none reach a critical state (“freezer too warm!!”)
I’m sure with effort, such systems could be created - a smart home monitoring system, WiFI temperature devices for freezers and hot water tanks, instead of dumb thermostats. Just for now, the demand is not so critical that the data inputs or control systems are there yet.
For example, I can program the amperage and times for charging my Tesla - but for now, it does not vary those depending on draw. Apparently, two shared Tesla home chargers can. And where it’s critical, where 8 or more Teslas could be trying to draw 350V 250A supercharging, the control equipment is quite capable of adjusting demand to limit total draw for the installation.
How many millions of devices would need to be upgraded for that to work? The vast, vast majority of appliances are ‘dumb’ & can’t talk to anything; maybe some could be updated with an IoT thermostat like a Nest but there is no external control for a fridge or hot water heater. What is the both financial cost & the resource cost (landfill space alone for all of them to get tossed) to now toss a full-functional but stand alone appliance? Would then then need to be replaced every couple of years despite otherwise working much like I need to buy a new PC because MicroSquash no longer supports Windows version ___?
During the Biden years (when renewables and demand-side energy management were still “hot” and politically acceptable), I worked for a Fortune 500 company working on just such a product. It could talk to some devices via APIs, or would switch others on/off via simple pulse width modulation, turning them on and off as needed. It wouldn’t meet EVERY use case, but the goal was to make it usable for many types of households.
That company wasn’t the first, either — I had worked with something similar to that a decade prior (in fact I think that company was bought out by the one I ended up working for, years later). The effort is still ongoing, I think, but post-Trump and post-COVID interest rates, the team suffered a ton of layoffs and cutbacks and it’s just barely petering along now. US renewables and energy management is a wee little boat caught in the political tides (or tsunamis, these days). The technical difficulties are complex but solvable. The political? Forget it.
It depends on the particulars. Some are retrofits that work with existing devices (some/many, but never all, of them). Some are meant for new constructions only.
The way these things usually work is that some state or county tries it out on an experimental basis, then maybe rolls it out into a new regulation in zoning law, then maybe years later retroactively applies it to some subset of existing households, then enough residents push back and stall the effort and eventually the federal government becomes Republican again and it all goes away anyway, only to restart the cycle with the next blue admin. It’s usually like one step forward three steps back in that regard, which is bad for the environment but good for homeowners who don’t want to change.
We just don’t really have the collectivist culture here to effectively do something like this at the community scale. “My house, my rules” is the norm and people don’t like their energy needs being rationed or limited to particular times of day. It takes a lot of political pushing (or consistent grid failures) for something like that to get implemented.
I’d say generally speaking, existing households and appliances are grandfathered in, but the next time you need to replace it, remodel, add solar, add an ADU, change to a different electrical utility or plan, or something similar… that’s when the new rules tend to get you, and they’re almost always less favorable to the homeowner / electricity consumer.
Energy policy is something that affects every citizen every day, but isn’t sexy enough for any politician to really talk about, much less for voters to study or care about enough. I don’t think this will change as long as the US military remains strong enough to guarantee a steady flow of energy and fossil fuels remain cheap enough that electricity pricing is more or less an afterthought. Were that not the case, we’d probably end up more like Europe (where things like air conditioning are taken a lot less for granted and heating systems are typically more efficient than just burning fossil fuels for resistive heat).
My mother in law’s new fridge has time-of-use options, and this can only be controlled by an app through the LG cloud. Going from memory, I think the fridge can be set to avoid running a defrost cycle or the icemaker during certain times of day to shift more power use to times electricity is cheap. Extending this to be controlled by an LG home hub, to coordinate with your other LG appliances, for a monthly subscription fee to LG seems like something they could do.
Oh yeah, the paths of enshitification and exploitation are numerous.
My two largest electricity users, the AC and charging the car, are already under the control of Xcel (the power company). Both of those are managed in the interest of grid stability, but instead managing them to limit my peak demand is only a matter of changing the algorithm, not changing what is being done.
Instead of trying to tie every appliance together into a network, there is a simple way to get the total. The total is what you really want anyway. All of the power for all of them is flowing through the main breaker. The original problem @md-2000 was trying to deal with is that sometimes there is too much going through that breaker and it trips. I’m suggesting that instead of trying to measure his toaster, garbage disposal etc. We take our measurement where it has already been added together for us. We measure it through that breaker and reduce power to the car only when we need to.
So whatever savings you have get eaten up by yet another subscription fee. Sounds wonderful (not).
Right, not every appliance needs to be smart. From a load perspective (kW) your refrigerator is small potatoes compared to the air conditioner, electric dryer, electric water heater, electric stove/oven, or car charger. The refrigerator certainly adds up over time (kWh) because it runs a lot, but it’s just a single 120v circuit and isn’t a big load on the system. There’s simpler devices than automated breaker panels too, such smart splitters that will allow only the clothes dryer OR car charger to run, but not both at the same time, giving preference to one (say the car charger in this case). Two or three of those (another use case is water heater vs clothes dryer) would get you 90% of the way there.
Even with all the smarts, though, it still comes down to having to learn to share a resource that previously seemed infinite (at least for many US households in living memory). Before the EV and mandatory electrification and time of use billing, you didn’t really have to think about which appliances you were allowed to run together, when, or care about what your neighbor was doing.
To go from that to having to juggle your appliances and knowing that your car may only be partially charged because your neighbor also needs some charge is a pretty big lifestyle difference, no matter how automated it is.
This is why I think first come first serve is the way to go for the OP. Once you really dive into the specifics with people who have no interest in this stuff, you’re likely to overwhelm them and get the whole project shut down. At the end of the day a lot of communities just can’t support the insane power draw EV charging requires once enough people have them, and a lot of homeowners don’t want to deal with the practical implementation details. Better to get in early before the rationing starts and it’s still relatively unlimited for your household.
That’s not meant to be an anti-EV stance, mind you (we have an EV too as our only car and love it), just a recognition of the limited amount of power available to many residential homes and areas. Our aging infrastructure as it is cannot keep up with a majority EV future without massive overhauls. The bandaids like load juggling buy us a little time, but eventually if there are enough EVs, it will be a problem where nobody can fully charge overnight anymore because there are too many people sharing. It’s the same issue you already get today at overcrowded level 3 chargers, but at a bigger scale.
This may be the thing that makes home solar more viable. It’s not cost effective (from a payback point of view) in most situations.
My house is a mere 113 years old. It has 100 amp service. To get the proper current out to the garage, my electrician installed a fused, 50-amp connection running off the meter, on the outside of the house instead of running it from my main panel inside the house. This prevented issues with running AC, fridge, and other high drain devices while the EV is charging.
I’m in a house from a similar time to you, but upgraded to 200A service. I don’t have an EV yet, so the biggest power usage would be the heat pumps, oven, or clothes dryer.
I just checked with my provider and my peak usage over the last 12 months was 44A.
Yeah I am not sure I actually needed it separate because most of my heat-generating appliances (furnace, oven, dryer) run on Natural Gas, but we did it this way for 2 reasons:
The 100A service limitation, just in case…
Saved a TON of labor and wire expense. To get from the main panel to the garage, I would have had to run a line through an inaccessible crawlspace toward the back of the house OR run it out the side of the house and had conduit visible all along the side of the house (there’s a paved driveway there, so putting it underground there was a non-starter as well. The meter is right on the back of the house, so splitting off another circuit from it was much simpler, and then all I had to do (ha!) was dig a 50-ish foot trench, 18 inches deep, to the garage.
16 posts in. It’s time to show how Green Acres explained - and solved - the problem 60 years ago.
Ah, yes, I remember this - a classic. Now, time to go shooping.
I imagine a bunch of kludges that might help. Some things, like the overn, the dishwasher and the dryer, you can manually time. For others - the fridge, the freezer - you could have something like air tags but with a temperature sensor, which talks to the central controller, and then turns the devices off and on with a controlled outlet if there’s a need to dial back. But, AFAIK, there’s no interface to the NEST to tell it - let the house heat up a little before kicking in the AC… or even “run the AC a bit longer so we can let it go for a while.”
[citation needed]
If everyone was using DC fast chargers, yeah sure that’s a problem. However all the data I’ve seen is that we need to grow our electricity generation and distribution system by 1% per year if we want every vehicle to be electric by 2050. We’ve been increasing such capacity by 3.2% per year for the last 70 years. Going from 3.2% to 4.2% annually isn’t nothing, but it’s not that big a deal, and we’re not going to have 100% electric vehicles by 2050 anyway.
This presumes the wiring from the meter to the pole service can handle 150A (and 120A constant load) without updating the wires.