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I'm in the midst of trying to get an electric car charger installed in my garage. Don't shoot the messenger. I live in Las Vegas, in a 25-year-old subdivision.
by BrentOzar 4y ago
I'm in the midst of trying to get an electric car charger installed in my garage. Don't shoot the messenger.
I live in Las Vegas, in a 25-year-old subdivision. 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.)
So to add a charger, I have to get my home's service raised to 400 amps. That wouldn't be a big deal, except... the neighborhood's transformers are already over capacity, too. A few of the homes already added 400-amp service so they could add Tesla chargers, and there's no capacity left in the neighborhood.
Nevada Energy is willing to add a new transformer in the neighborhood - but they want to charge me $20,000, plus the costs of trenching the new 400-amp line from the transformer to my house, plus the new panel, plus the charger. It's looking like a $40,000 installation.
Or... I could just put solar on the roof, build a separate isolated 200-amp panel powered by solar, and charge the car from that. (Plus move over the pool pumps, hot tub, etc while I'm at it.) That isn't free, either, but at least it'd cut my electric bills long term instead of adding to 'em.
I don't know how many homes & neighborhoods are in this situation, but I was surprised that a 25-year old neighborhood is having this problem.
- hnburnsy 4y agoShare 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.
- modeless 4y agoA 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.
- rootusrootus 4y agoHow 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.
- mcbishop 4y ago> Just time your charging so it's when you're sleeping, not cooking and doing laundry. But there's also passing inspection.
- rootusrootus 4y ago> 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.
- BrentOzar 4y agoThat's the problem - the city's inspection assumes full load from each of the appliances, plus some.
- mcbishop 4y ago> 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
- mywittyname 4y agoI'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.
- lostlogin 4y agoDo 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.
- cyberax 4y ago> 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 https://youtu.be/CVLLNjSLJTQ?t=793
- twblalock 4y agoIn 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.
- cyberax 4y agoThe new NEC actually allows flexible loads. So check if your locality has adopted the 2021 (AFAIR) version of the NEC.
- twblalock 4y agoQuite 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.
- sib 4y agoWe 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/ https://dccelectric.com/dcc-9/
- adanto6840 4y agoWow, 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. :)
- bit_logic 4y agoWe 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.
- tstrimple 4y ago> 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.
- adgjlsfhk1 4y agoyeah. 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.
- fwungy 4y agoA 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.
- cryptoegorophy 4y agoNot 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
- throwaway742 4y agoThis. 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.
- newZWhoDis 4y agoI 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.
- theshrike79 4y ago200A?! 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.
- mercutio2 4y ago200A in the US is 24kW.
- m463 4y agoSounds 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.
- alex_duf 4y agoThat'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?)
- justrealist 4y agoPool, 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.
- sf_rob 4y agoOr as King of the Hill (TV Show) says of Phoenix: "This city should not exist. It is a monument to man's arrogance."
- cryptonector 4y agoIt'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.
- seb1204 4y agoNot 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?
- dandy23 4y agoPeople use clothes driers in Las Vegas? No wonder there is global warming.
- rendang 4y agoI 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
- code_runner 4y agoMy 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)
- lultimouomo 4y agoI 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.
- rendang 4y agoYou'd prefer he strung out a line in his backyard & hung all his clothes outside like they do in developing countries?
- ketkev 4y agoYes of course? Not everything needs to go in an energy intensive dryer. It'll air dry just fine inside or outside
- BeFlatXIII 4y agoOh no, he might look gasp _poor_ and lower neighborhood property values, thus cheating responsible savers out of their well-earned retirements.
- campl3r 4y agoYes? I prefer to do that myself
- lultimouomo 4y agoI 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.)
- rendang 4y agoNot offensive, just more labor intensive and uncommon in the US, especially for someone well-off enough to have his own pool.
- 4y ago
- Robotbeat 4y agoJust 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.