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Building a house - what to install?

Discussion in 'Charging Standards and Infrastructure' started by Randy7fx, Mar 6, 2017.

  1. Randy7fx

    Randy7fx New Member

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    Hi All,

    I am in the process of going under contract for a new construction home, and am trying to figure out what I should do in my garage to prepare for getting a Model 3 when it finally comes out. Is there a definitive thread on this? I am not even sure what my options are at this point, but will need to tell the builder what I want to do within two weeks or so. Can someone point me in the right direction please. Thanks so much.
     
  2. Rocky_H

    Rocky_H Active Member

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    You don't need to have a completed solution in place while building the house. Getting the wire in the wall is the important part, but you don't have to install an outlet or wall connector on the end until you decide later what to do. Just find out how many amps the main electric service for the house has and how many amps you can spare for charging, and then have wire thick enough to handle that run to the location you want. Then, you can just cap the ends of the wire and put a blank cover plate over it until you decide to install something there. As for the location, the Model 3 almost positively will have the charging port at about the same location as the Model S and X, at the rear left of the car. It pretty much has to, to use the Superchargers. So figure out how you're going to park in your garage and get the wire run to somewhere close enough that it can reach that side of the car.
     
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  3. KJD

    KJD Supporting Member

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    The model 3 details still have not been released yet, so right now its a bit of guess work. Having said that the 3 will most likely be similar to the current Model S as far as charging options.

    I would just have them install a NEMA 14-50 outlet in the garage and call it good. There is a home charging FAQ with lots of info here.
    FAQ: Home Tesla charging infrastructure Q&A
     
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  4. brucet999

    brucet999 Active Member

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    #4 brucet999, Mar 6, 2017
    Last edited: Mar 6, 2017
    If you are building a new house, there is no reason not to have a panel big enough to support a 100A circuit for EV charging (check with your utility to be sure the supply to your new house is capable of supporting a big panel). Then you need wiring installed sufficient for a 100A circuit to the charging location - within 15 feet of the left rear of your car (I know the cables are longer, but you need slack to reach down to the floor without making a tripping hazard).

    Yes, you can get by with just a 50A outlet (NEMA 14-50) for charging M3, but what will the charging capacities be on future EVs that you might own? If you are wired for 100A, you can easily downgrade to 50A breaker and outlet, but you couldn't easily upgrade from 50A wiring to 100A.

    Are you likely ever to have two EVs? You might want to have panel capacity and wiring pulled for a second EV charger.

    You also didn't say whether you plan to install solar panels. Many permitting authorities stupidly limit solar input to 20% of panel rated capacity. On a 200A panel, that would limit you to 9.6 kW of solar. The difference in cost between a 200A panel and 400A panel is only about $500, so you might want to build in room for solar even if you won't install it right away.

    Also, make sure that your contractor will not skimp on wiring. I have seen many houses where they installed 14AWG wire for convenience outlet circuits (instead of the customary 12AWG 20A circuits), limiting the whole circuit to only 15A, which is not enough for a floor heater and hair dryer to operate at the same time. Since two or three bathrooms are often wired on the same circuit, hair dryers in two bathrooms at once could trip a 15A breaker.
     
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  5. Randy7fx

    Randy7fx New Member

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    Thanks so much for the feedback all. Very helpful!

    Regarding the solar question, yes, the house will have solar (from Solar World) from the start (the builder is building this small community of 20 homes as a "solar community", so all 20 will actually have solar installed. Are there specific questions I should be asking the builder as it relates to this?
     
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  6. TexasEV

    TexasEV Well-Known Member

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    Another option is just to have conduit run in the wall from the breaker box to a junction box in the garage. Then when you get your car you can decide if you want a 14-50 outlet or higher amp charging with a HPWC, and the electrician can come back to install the proper breaker and pull the wire through the conduit.
     
  7. brucet999

    brucet999 Active Member

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    1. You need to know the rules that your poco applies to net metering. For instance, can you sell excess power at retail rates, or do they pay a low wholesale rate, making excess capacity uneconomical. What limit do they apply to your PV output? SoCal Edison uses a square footage limit calculation on new construction (existing houses are limited to the past 12 months' billings) that surely will not allow for your M3 usage, so you need to find out how to build in extra capacity for EV usage.
    2. You need to make sure that the builder is installing large enough service panel to take the PV output if the 20% rule applies in your area.
    3. you want to be sure that the system has power optimizers installed so that each panel operates at highest possible output even if one or more panels are shaded, dirty or damaged. In conventional strings, one under-performing panel drags the output of the whole array down, like one bad battery in a flashlight. Power Optimizer | SolarEdge
    4 See if you can specify SolarSkin on your SolarWorld panels (Sistine uses SolarWorld and LG panels). They can mitigate the ugly-factor of panels with very slight capacity loss. Maybe the builder could do the whole tract with camouflaged panels so panels visible from the street would be disguised. Better yet, would be Tesla Solar Roof, but that may not be available until late 2017 (Tesla time).
    SolarSkin: Solar Panel Designed to Blend In I Sistine Solar
    5. Does your poco have time of use metering? If so, a Tesla Power Wall could be a good investment in order to shift consumption to battery during peak rates time and allow operating off-Grid during power failures. Tesla's inverter can automatically disconnect from the Grid (required of all inverters for the safety of poco crews trying to fix an outage) and switch to battery for all or part of your load, then automatically switch back when Grid power is restored.
    6. If battery storage is installed (or to enable batteries to be installed later), you may want certain critical circuits like fridge, freezer, water heater (even many gas WHs need power to run igniters for the burner), lighting, sump pump, etc. to be segregated from the main panel so battery load can be minimized to last through lengthy power outages if such are common in your area.
     
  8. miimura

    miimura Active Member

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    For EV charging, I suggest that you have the electrical contractor install a 240V NEMA 14-50 socket for each garage parking space. During construction, I specified mine on the side walls of my two-car garage. A good location is about 6 feet from the garage door. The left space is ideal for most plug-in vehicles since they have the charge port on the driver's side. Exceptions include the VW e-Golf, BMW i3, Fiat 500e, Prius Plug-In and Prime, and Mercedes Plug-In hybrids because they have the port on the passenger side. The Leaf, Kia Soul EV, and Audi A-3 e-Tron have the charge port in the front which is easy to reach from the side with normal cable lengths.

    If you want to go big, then a 100-125 amp sub-panel in the garage would give you the most future flexibility for higher power charging. However, I doubt you will be wanting for more if each car has a 50 amp circuit dedicated to its parking space.
     
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  9. strider

    strider Active Member

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    +1 @miimura Put a NEMA 14-50 on each side of the garage door (assuming a 2-car garage) about 3ft above the floor. That will give you maximum flexibility for an EV from any manufacturer.
     
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  10. miimura

    miimura Active Member

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    Normal height for this kind of outlet is +48" above the finished floor. This ends up being very convenient for flush mounted EVSE like the Tesla Wall Connector, or the Leviton EVB40 shown below.

    Leviton Installation_r.jpg

    You can see here that the electrical contractor put the standard outlet and the 240V outlet at the same height, without any instruction from me.
     
  11. BrokerDon

    BrokerDon Member

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    I'd also run Cat5e or Cat3 Ethernet wires to your garage (for a WiFi extender if needed or digital Submetering for your EV) and main service panel in case you add solar or want real time read outs on your energy consumption.
     
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  12. TexLaw

    TexLaw Member

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    That's brilliant. I never would have thought of that.

    I agree that the minimum you want would be to install a 100A subpanel in your garage (or more if you think you want to put something like a freezer, refrigerator, shop, etc. in there). If your local service can handle that, it's not all that expensive to do it when you're building the house, The biggest expense is the dadgum wire! Installing the aforementioned NEMA 14-50 outlet is not much more expense, either, and that will serve you and your Model 3 quite well.
     
  13. strider

    strider Active Member

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    Good point. I just went and measured mine (I was guessing in my reply above) and it's 42" off the floor so 3.5 feet. It works great at that height w/ both Model S and Roadster UMCs. So 3.5'-4' would work well.
     
  14. arnis

    arnis Member

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    #14 arnis, Mar 16, 2017
    Last edited: Mar 16, 2017
    Most important is the overall design of the area around the house.
    Where will you leave the car overnight? In garage, next to garage door on the driveway, further
    away from the house on the driveway or next to the street far away from the house?

    In case you leave your car further away from the house wall/perimeter than 2m (4-5 steps) you should
    have your plug closer to the spot you leave the car.

    My parking spot is on my driveway that is 15-20 steps from the house. I had to dig a small ditch to
    bury the stuff. EVSE (device with the plug) is on a small pole, similar to regular metal fence-post.
    So it would be smart to have the big conduit already waiting when you get your EV.
    In addition to just EVSE, I added 230V outlet for vacuum cleaner and pressure washer. And also
    waterline (with heating cable wrapped around so I could use it in winter too).

    You can see EVSE, 230V IP54 socket and water outlet down below. You need separate cable for regular outlet with separate circuit breaker. I can actually charge 2 EV-s simultaneously, one with EVSE and other one with portable charge. Or charge and clean my car simultaneously.

    Aim at being able to plug in Model 3 within 5 seconds after closing the drivers door. I need 4 seconds with my Leaf.

    [​IMG]

    [​IMG]
    [​IMG]
     
  15. David_Cary

    David_Cary Member

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    NC specific advice.

    Do you have Duke Energy? I believe they cover the urban areas of the state (and most of the rural). Today they require all solar installs to be on TOU-D rate structure. In my day, I got some coin to have this rate plan for 5 years but my understanding is that it is a requirement for all solar installs.

    This rate structure has a demand charge. That means it takes your highest on peak usage in a 15 min period and assigns a surcharge for that. So you can plug your car in and charge at 10kw (if you have an S - up to 20) and pay a significant charge that month. Currently it is $5.50 per kw in summer and less in winter. I typically hit 4-5 kw - sometimes higher in winter with a heat pump. Otherwise the rates are extremely cheap. With a big solar setup, the surcharge can dominate your monthly bill. I know people that routinely hit 20 kw.

    What to do - ie what I would have done differently. Gas dryer. The misses doesn't like being told when to run the dryer. Gas oven wouldn't hurt. Stay away from heat pumps with electric backup. We have NG backup on the heat downstairs and that is all we need - but I do have to be careful upstairs - the only time it was an issue was with an errant guest.

    If you do not have NG - ouch. That is all I can say. Large water tank to put on a timer.

    What I fear is that you are building in a "solar" neighborhood with no access to NG. Then on demand electric hot water. And you could be in for obnoxious electric bills. That combined with the relatively small solar install and you can be in for a world of hurt.

    On the plus side, my night time rate is $.05. I have 5,000 sqft, 2 evs, electric-solar hot water/hp/electric oven 5 kw system and I usually run $50-$70 a month and $120 a year in gas usage. April and May - the peak change dominates.
     
  16. jbcarioca

    jbcarioca Active Member

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    Almost anywhere that photoelectric can work, solar hot water can too. It is easy, cheap and reliable, and uses electricity only for pumping, if at all. It also lasts essentially forever.
     
  17. KJD

    KJD Supporting Member

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    Would the Powerwall 2 be cost effective for these people ?

    If I were building a new house it would have a NEMA 14-50 in at least 2 parking stalls for starters.
     
  18. David_Cary

    David_Cary Member

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    It is absolutely possible the Powerwall would be cost effective. Would the PoCo allow it? They are within their rights to not I suspect. But they might not care. The spread between our peak rates and off peak are minimal - $.07 and $.05 roughly. That is right a $.02 spread. It is all about the peak. So no incentive to charge battery at off peak just to use on peak. Only for peak shaving which is presumably what they want.

    Other planning I forgot to mention is small a/c units or staged. Good idea anyway but peaks in summer are usually 8-9 pm running all the a/c units. I am able to run downstairs until 6 pm (restricted to stage 1) and then run upstairs from 6 on. I do a lot of playing the game.

    Solar hot water is pretty dead. Coolant does not last forever. Pumps do not last forever. Leaks occur - I had 2 in the first year but then nothing sense then. 5 year change out of coolant is recommended - I haven't done it after 7 years. Tanks eventually fail - and a solar tank is going to be more expensive than the alternative. The fact is PVs are cheaper for what they give you. Yes - when you need the hot water - solar hot water is helpful. But the big problem is the delta between July and December and nothing you can do with the excess in July. December produces 20% of July (in my latitude) and you need to somewhat size for that.

    Our utility (Progress at the time) did a nice study which I got paid to participate. Average user in our area was $300 a year and solar saved $200. Nice. $6500 cost so 32 year payback ignoring subsidies, time of money, maintenance costs. That roof space is better used with PV. Much quicker payback. Mind you NG tankless would be $200 a year (roughly). Now I got ridiculous subsidies - 65% plus $1000 from utility for participating in the study. My net was almost zero considering it was new construction so $1000 for a conventional tank with install is about right. I also have a recirc pump that raises usage dramatically so there is that.

    I have solar hot water but I won't do it again. Not with today's PV prices. Not with requirements for freeze control - ie not Rio or S Florida I'm guessing. The green building forums tend to agree with that assessment. Now - the truth is solar hot water helps for peak control. So if you only have electric and you have peak charges - then it starts to make sense again. Hot water is a great storage medium. If a day is going to be cloudy, I can heat some extra water off peak. I can also get away with a 1 kw heating element during the day. So hot water doesn't contribute to my peak at all. But I have 130 gallons of tank to support that.
     
  19. jbcarioca

    jbcarioca Active Member

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    It's too bad about your poor experience. The solar hot water system my father built in Ohio in 1951 still operates well year around. Storage must be carefully planned as must winterization and capacity planning. The current practices in some area do tend to reduce practicality, not to mention introducing lots of maintenance and leakage issues. About that I agree. It does not need to be that way. It rather seems your system must have been designed by people intending to make it impractical.

    This is in some ways analogous to the deep underground temperature stabilization systems that make heating cheaper and air conditioning too. They are simple, and overcomplicsting the solution usually makes it poorer, not better.

    I'm not arguing for such solutions everywhere. The higher the altitude, the further from the Equator the less well passive systems tend to work. There is little question about that.

    OTOH, our air conditioning bill in Rio de Janeiro for a very large house is zero, with a combination of deep thermal radiation and air circulation. We're the only house we know of that dies not have a/c and visitors are always astonished that it is possible to be comfortable without A/C.
     
  20. thx1139

    thx1139 Member

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    We are building new house now as well. We are having an additional 200AMPs brought to the house and having 3 50AMP circuits installed in the garage. Immediately that will charge our S and our 2 Volts which some day in the future will be replaced by 1 or 2 Model 3s. We also plan on adding Solar, but in Illinois I dont believe any benefit of having PowerWalls installed.
     
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